E
MARINE ENVIRONMENT PROTECTION
COMMITTEE
61st session
Agenda item 2
MEPC 61/2/9
28 March 2010
Original: ENGLISH
HARMFUL AQUATIC ORGANISMS IN BALLAST WATER
Application for Final Approval of the Severn Trent De Nora BalPure®
Ballast Water Management System
Submitted by Germany
SUMMARY
Executive summary:
This document contains the non-confidential information related to
the application for Final Approval of the Severn Trent De Nora
(STDN) BalPure® Ballast Water Management System under the
"Procedure for approval of ballast water management systems that
make use of Active Substances (G9)" adopted by resolution
MEPC.169(57)
Strategic direction:
7.1
High-level action:
7.1.2
Planned output:
7.1.2.5
Action to be taken:
Paragraph 5
Related documents:
BWM/CONF/36; MEPC 57/21; BWM.2/Circ.13 and BWM.2/Circ.24
Introduction
1
Regulation D-3.2 of the International Convention for the Control and Management of
Ships' Ballast Water and Sediments stipulates that ballast water management systems that
make use of Active Substances to comply with the Convention shall be approved by the
Organization.
2
The Procedure for approval of ballast water management systems that make use
of Active Substances (G9) stipulates the required information (MEPC 57/21, annex 1,
paragraph 4.2.1) and provisions for risk characterization and analysis (MEPC 57/21, annex 1,
section 5), which, according to section 6 of Procedure (G9), should be evaluated by the
Organization.
3
Basic Approval of the Severn Trent De Nora (STDN) BalPure® Ballast Water
Management System was granted at MEPC 60.
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4
The receiving competent authority in Germany has verified the application dossier
and believes it to satisfy the data requirements of Procedure (G9) adopted by resolution
MEPC.169(57). In accordance with BWM.2/Circ.24, Germany therefore submits the
non-confidential part of the manufacturer's application dossier in the annex. The complete
dossier will be made available to the experts of the GESAMP-BWWG with the understanding
of confidential treatment.
Action requested of the Committee
5
The Committee is invited to consider the proposal for approval and decide as
appropriate.
***
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ANNEX
NON-CONFIDENTIAL INFORMATION ON THE SEVERN TRENT DE NORA BALPURE®
BALLAST WATER MANAGEMENT SYSTEM
CONTENTS
LIST OF ABBREVIATIONS
1
INTRODUCTION
1.1
1.2
Overview of the BalPure® technology
Response to the GESAMP-BWWG's comments on the application for Basic
Approval
2
IDENTIFICATION OF THE ACTIVE SUBSTANCES AND RELEVANT CHEMICALS
(G9: 4.1)
2.1
2.2
2.2.1
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.4
2.4.1
Introduction to the chemical basis of BalPure® Ballast Water Management System
Active Substances
Hypochlorous acid and hypobromous acid
Relevant Chemicals
Trihalomethanes (THMs) and haloacetic acids (HAAs)
2,4,6-Tribromophenol
Bromate, chlorate and monobromoacetonitrile
Hydrogen gas
Other chemicals
Sodium bisulfite and sodium bisulfate
3
DATA ON EFFECTS ON AQUATIC PLANTS, INVERTEBRATES AND FISH, AND
OTHER BIOTA, INCLUDING SENSITIVE AND REPRESENTATIVE ORGANISMS
(G9: 4.2.1.1)
3.1
3.2
3.3
3.4
3.5
3.6
Acute aquatic ecotoxicity
Chronic aquatic ecotoxicity
Endocrine disruption
Sediment toxicity
Bioavailability/biomagnification/bioconcentration
Food web/population effects
4
DATA ON MAMMALIAN TOXICITY (G9: 4.2.1.2)
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
Acute mammalian toxicity
Effects on skin and eye
Repeated-dose toxicity
Chronic mammalian toxicity
Developmental and reproductive toxicity
Carcinogenicity
Mutagenicity and genotoxicity
Toxicokinetics
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5
DATA ON ENVIRONMENTAL FATE AND EFFECT UNDER AEROBIC AND
ANAEROBIC CONDITIONS (G9: 4.2.1.3)
5.1
5.2
5.3
5.4
5.5
5.6
Modes of degradation (biotic; abiotic)
Bioaccumulation, partition coefficient, octanol/water partition coefficient
Persistence and identification of the main metabolites in the relevant media
Reaction with organic matter
Potential physical effects on wildlife and benthic habitats
Potential residues in seafood
6
PHYSICAL AND CHEMICAL PROPERTIES FOR THE ACTIVE SUBSTANCES,
RELEVANT CHEMICALS, AND TREATED BALLAST WATER (G9: 4.2.1.4)
7
ANALYTICAL METHODS AT ENVIRONMENTALLY RELEVANT CONCENTRATIONS
(G9: 4.2.1.5)
7.1
7.2
Analysis of Total Residual Oxidants (TRO as Cl2)
Analysis of Disinfection By-products (DBPs)
8
USE OF ACTIVE SUBSTANCE
8.1
8.1.1
8.1.2
8.1.3
Manner of application
Process flow description
Chemical storage and handling
Various procedures and management measures
9
MATERIAL SAFETY DATA SHEETS (G9: 4.2.7)
10
RISK CHARACTERIZATION AND ANALYSIS
10.1
10.1.1
10.1.2
10.1.3
Screening for persistence, bioaccumulation, and toxicity (G9: 5.1)
Persistence (G9: 5.1.1.1)
Bioaccumulation (G9: 5.1.1.2)
Toxicity tests (G9: 5.1.2.3)
11
EVALUATION OF THE TREATED BALLAST WATER (G9: 5.2)
11.1
11.2
11.3
11.4
11.5
11.6
11.7
11.8
11.8.1
11.8.2
11.8.3
11.9
11.10
11.11
11.12
11.13
Total Residual Oxidants
Water quality parameters
Chemical analysis of disinfection by-products in treated ballast water
Ecotoxicity testing of treated ballast water, land-based testing
Determination of holding time
Reaction with organic matter
Characterization of degradation route and rate (G9: 5.3.5)
Prediction of Discharge and Environmental Concentrations (G9: 5.3.8)
Hydrodynamic modelling approach
Determination of substance concentrations and decay rates for modelling input
Predicted Environmental Concentration results from MAMPEC modelling
Effects on aquatic organisms
Assessment of potential for bioaccumulation
Effects on sediment
Effects assessment
Comparison of effect assessment with discharge toxicity
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12
RISK ASSESSMENT
12.1
12.1.1
12.2
12.2.1
12.2.2
12.2.3
12.2.4
12.2.5
12.2.6
12.3
Risk to safety of ship
Corrosion
Risks to human health
Introduction
Hazard identification/chemical of potential concern selection
Human Exposure Scenario
Health effects in humans
Risk characterization
Risk assessment conclusions
Risks to the aquatic environment
13
ASSESSMENT REPORT
14
REFERENCES
APPENDICES (provided in confidential dossier)
A.1
A.2
A.3
A.4
A.5
A.6
A.7
Key Data Table Summary
Human Exposure Assessment
BalPure® Process Flow Diagram
Material Safety Data Sheets/International Chemical Safety Cards
Analytical Method Information
Laboratory Quality Assurance Documents
Corrosion Information
LIST OF TABLES
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Table 10
Table 11
Table 12
Table 13
Table 14
Table 15
Table 16
Table 17
Table 18
Table 19
Table 20
Table 21
Table 22
Table 23
Table 24
Overview of Chemical Identification
Acute Aquatic Ecotoxicity Data
Acute Aquatic Ecotoxicity Data – Land-based Testing
Overview of Chronic Aquatic Ecotoxicity Data
Chronic Aquatic Ecotoxicity Data – Land-based Testing
Koc Values for Relevant Chemicals
BCFs for Relevant Chemicals
Acute Mammalian Toxicity Data
Effects on Skin and Eye
Repeated-dose Toxicity
Chronic Mammalian Toxicity
Summary of Developmental and Reproductive Toxicity Data
Summary of Data on Carcinogenicity
Summary of Data on Mutagenicity and Genotoxicity
Summary of Uptake, Absorption, and Excretion of Chemicals
Fate and Mode of Degradation for Relevant Chemicals
Physical and Chemical Properties of Relevant Chemicals
Analytical Methods
PBT Criteria Evaluation
Average Oxidant Values (mg/L) in Treated Ballast Water
Water Quality Data
Post-Treatment Disinfection By-product Concentrations – Day 1
Post-Treatment Disinfection By-product Concentrations – Day 5
Median Disinfection By-product Concentrations
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Table 25
Table 26
Table 27
Table 28
Table 29
Table 30
Table 31
Table 32
Table 33
Table 34
Table 35
Table 36
Table 37
Table 38
Table 39
Summary of Relevant Chemical Concentration and Half-life for Modelling
PEC Summary for Environment A and Environment B
PNEC Derivation Summary
PEC/PNEC Calculation for MAMPEC Environment A
PEC/PNEC Calculation for MAMPEC Environment B
Comparison of Basic Approval and Land-based Ballast Water Residual COPC
Exposure Point Concentrations
Summary of Dermal Intake Factors
Summary of Oral Intake Factors
Summary of Toxicity Criteria
Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians
Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians
(or Others) – Ballast Water Discharge Sampling
Summary of Cancer Risks and Non-cancer Hazards for Ship's Crew/Dock
Workers
Summary of Cancer Risks for the General Public
Summary of Non-cancer Hazards for General Public
Estimated Concentrations of THMs in Vent Air and Comparisons to PELs
LIST OF FIGURES
Figure 1
Figure 2
Figure 3
Overview of the BalPure® Ballasting Process
Overview of the BalPure® Deballasting Process
Conceptual Exposure Model, BalPure® System
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LIST OF ABBREVIATIONS
Abbreviation
Description
Abbreviation
Description
AIS
BCAA
BCF
Br2
BWMS
CAS
ClCl2
CO2
CO
COPC
DBAA
DBCAA
DBCM
DBPs
DC
DCAA
DCBM
DO
DOC
DPD
Aquatic Invasive Species
Bromochloroacetic acid
Bioconcentration Factor
Bromine
Ballast Water Management System
Chemical Abstract Service
Chloride ion
Chlorine
Carbon dioxide
Carbon monoxide
Chemicals of Potential Concern
Dibromoacetic acid
Dibromochloroacetic acid
Dibromochloromethane
Disinfection By-products
Direct Current
Dichloroacetic acid
Dichlorobromomethane
Dissolved Oxygen
Dissolved Organic Carbon
N,N-diethyl-p-phenylenediamine
Effective concentration of
substance that causes 50% of
maximum response
Endocrine Disrupting Chemicals
Exposure Point Concentrations
Estimation Programs Interface
Free Available Chlorine
Free Available Bromine
Joint Group of Experts on the
Scientific Aspects of Marine
Environmental Protection – Ballast
Water Working Group
Hydrogen ion
Hydrogen gas
Hydrogen peroxide
Hazardous Substances Data Bank
Bisulfite ion
Bisulfate ion
Haloacetic acid
Hypobromous acid
Hypochlorous acid
International Agency for Research
on Cancer
International Maritime Organization
International Union of Pure and
Applied Chemistry
Organic Carbon Partition
Coefficient
Octanol/Water Partition Coefficient
Kilopascal
Litre per kilogram
Lethal Concentration for 50% of
test population
Lethal Dose for 50% of test
population
Lower Explosive Limit
Lowest Observable Adverse Effect
Level
m
MBAA
MCAA
MEPC
mV
μg/L
Metres
Monobromoacetic acid
Monochloroacetic acid
Marine Environment Protection Committee
Millivolts
Micrograms per litre
Marine Antifoulant Model to Predict
Environmental Concentrations
Milliampere
Micromolar
Milligrams per litre
Material Safety Data Sheet
Sodium bisulfite
Sodium hypochlorite
Netherlands Institute for Sea Research
No Observed Adverse Effect Level
No Observed Effect Concentration
No Observed Effect Level (used
interchangeably with NOAEL)
Hypobromite ion
Hypochlorite ion
Organization for Economic Co-operation
and Development
Operator Interface Terminal
Oxidation Reduction Potential
Predicted Environmental Concentrations
Persistence, Bioaccumulation, Toxicity
Process Flow Diagram
Dissociation Constant
Programmable Logic Controller
Predicted No Effect Concentration
Particulate Organic Carbon
Personal Protective Equipment
Parts per million
Practical Salinity Units
Structure Activity Relationship
Screening Information Data Set
Severn Trent De Nora
Tribromoacetic acid
2,4,6-Tribromophenol
Trichloroacetic acid
Trihalomethane
Total Organic Carbon
Toxicology Data Network
Total Residual Oxidants
Total Suspended Solids
United States Environmental Protection
Agency
EC50
EDCs
EPC
EPI
FAC
FAB
GESAMPBWWG
H+
H2
H2O2
HSDB
HSO-3
HSO-4
HAA
HOBr
HOCl
IARC
IMO
IUPAC
Koc
Kow
Kpa
L/kg
LC50
LD50
LEL
LOAEL
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MAMPEC
mA
μM
mg/L
MSDS
NaHSO3
NaOCl
NIOZ
NOAEL
NOEC
NOEL
OBrOClOECD
OIT
ORP
PEC
PBT
PFD
pKa
PLC
PNEC
POC
PPE
ppm
PSU
SAR
SIDS
STDN
TBAA
2,4,6-TBP
TCAA
THM
TOC
TOXNET
TRO
TSS
US EPA
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1
INTRODUCTION
Severn Trent De Nora, LLC (STDN) has developed the BalPure® Ballast Water Management
System using seawater electrolysis combined with filtration and residual oxidant
neutralization. STDN's experience with electro-chlorination in a variety of industrial and
maritime settings has proven the effectiveness of the technology. Testing of the system in
the laboratory, during land-based testing and onboard ship has demonstrated the
technology's effectiveness for disinfection of aquatic invasive species in ballast water.
Land-based testing of the BalPure® system was conducted at The Royal Netherlands
Institute for Sea Research (NIOZ) during 2009. As required for Final Approval, an evaluation
of aquatic ecotoxicity and Relevant Chemicals (e.g., disinfection by-products (DBPs)) was
performed on samples drawn from the land-based test set-up. The quality assurance
documents for the laboratories that performed ecotoxicity and DBP analyses are included in
appendix A.6. Also presented are responses to comments of the GESAMP-BWWG
(MEPC 60/2/16) during review of STDN's application dossier for Basic Approval
(MEPC 60/2/9). STDN is submitting this application dossier to apply for Final Approval in
accordance with Procedure (G9) (resolution MEPC.169(57)).
1.1
Overview of the BalPure® technology
The BalPure® system provides a safe and economical electrolytic process for the on-site
generation of a biocide solution from seawater to disinfect aquatic invasive species (AIS) in
ballast water. Ballast water treatment is accomplished using a simple three-step process of
filtration, injection of a biocide solution, and residual oxidant neutralization. The first phase is
filtration using a 40 micron stainless steel mesh filter to remove organisms, large particles,
and sediments. The second phase of the treatment process is electrochemical generation of
the biocide solution. This involves passing a small supply (1/100 of total ballast flow) of
seawater, either from the incoming ballast water line or sea cooling water, through
electrolytic cells. The resulting disinfectant solution is injected directly into the incoming
ballast water line where it will oxidize potential AIS. The third and final treatment process
phase is residual oxidant neutralization to ensure environmental acceptability. When the
treated ballast water is ready to be discharged, sodium bisulfite is injected directly into the
ballast water discharge line. The sodium bisulfite (oxidant neutralization) addition is
controlled with ORP and metering pump technology.
The BalPure® system is designed to require minimal input from the ship's crew, with the
system starting and stopping the necessary treatment steps based on electronic signals.
This minimizes added duties to ship's crew and ensures proper ballast water treatment.
More detailed information regarding operation of the BalPure® system is included in section 8.
1.2
Response to the GESAMP-BWWG's comments on the application for
Basic Approval
Severn Trent De Nora submitted an application dossier for Basic Approval in August 2009
(MEPC 60/2/9). That dossier was reviewed during the 12th meeting of the GESAMP-BWWG
in December 2009 and Basic Approval was recommended. The recommendations and
comments by the GESAMP-BWWG (MEPC 60/2/16, annex 7), along with STDN's responses,
are summarized below:
.1
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The Group recommended that a comprehensive evaluation of the corrosion
impacts on ship's structures be conducted using the maximum anticipated
treatment concentration, 20 mg/L (TRO as Cl2) and that a realistic TRO
decay profile may be considered if the total corrosion loss over the ship's
MEPC 61/2/9
Annex, page 7
life is to be projected. The Group noted however that such an analysis,
while useful, is not necessary for the Group's consideration. The Group
recommended that corrosion testing be conducted, and invited the
applicant to consider the guidance provided in section 5.1 of the "Report of
the eighth meeting of the GESAMP-BWWG", contained in document
MEPC 59/2/16.
Response: Additional information regarding corrosion is presented in
section 12.1 "Risk to safety of ship". Further, STDN has initiated a detailed
corrosion study as recommended by the Group. The results of the study
will be considered as part of the Type Approval process with the German
Administration.
.2
The Group recommended to take into consideration the human exposure
during sampling of ballast water at discharge (inhalation, dermal contact),
as well as during periodic sediment cleaning (inhalation, dermal contact).
These scenarios should also be considered in the conceptual exposure
model (CEM).
Response: See section 12.2 "Risks to human health" for consideration of
human exposure during sampling of ballast water at discharge and during
periodic sediment cleaning.
.3
The Group recommended that the data sets on the analysis of Active
Substance, Relevant Chemicals and Other Chemicals in treated ballast
water should be further investigated during land-based and shipboard testing.
Response: STDN performed chemical analysis for Active Substances,
Relevant Chemicals and Other Chemicals on samples drawn from the
land-based test set-up. The human health risk assessment performed for
Basic Approval has also been updated to reflect the land-based testing
results. See section 11 "Evaluation of the treated ballast water" and
section 12.2 "Risks to human health".
.4
The Group recommended that confirmation by further testing should be
performed, that there will be no unacceptable risks (to ship safety, human
health, or the environment) due to the chemical composition of the ballast
water treated by this BWMS.
Response: See section 12.1 "Risk to safety of ship", section 12.2 "Risks to
human health", and section 12.3 "Risks to the aquatic environment".
.5
The Group recommended that all missing information concerning the
environmental exposure assessment using an appropriate model be provided.
Response: See section 11.8 "Prediction of discharge and environmental
concentrations".
.6
The Group recommended verification that the residual oxidant
neutralization with sodium bisulfate on discharge is effective at all ballast
discharges with MADC < 0.20 mg/L TRO as Cl2.
Response: See section 11.1 "Total Residual Oxidants".
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.7
The Group recommended that both acute and chronic ecotoxicity testing of
treated ballast water be performed in accordance with the full requirements
of Procedure (G9) at the maximum proposed treatment dose.
Response: As required by Procedure (G9), STDN performed ecotoxicity
testing of treated/neutralized ballast water on samples drawn from the
land-based test set-up. See sections 3.1 and 3.2 for Acute and chronic
aquatic ecotoxicity data (Tables 3 and 5) and section 11.4 "Ecotoxicity testing
of treated ballast water, land-based testing" for discussion of the results.
2
IDENTIFICATION OF THE ACTIVE SUBSTANCES AND RELEVANT CHEMICALS
(G9: 4.1)
2.1
Introduction to the Chemical Basis of BalPure® Ballast Water Management
System
The BalPure® system uses electrolysis of seawater to safely generate sodium hypochlorite
on board, and immediately injects the solution directly into ballast water while it is pumped on
board. Seawater is passed through electrolytic cells (electrolyzers) where it is subjected to
medium amperage, low voltage direct current. Electrolytic cells are comprised of a cathode
and an anode. At the outlet of the electrochemical generator, the seawater contains a
mixture of chemicals produced at both the anode and cathode. Because seawater contains
bromide ions, the electrochemical process results in the formation of hypochlorous acid (HOCl)
in equilibrium with hypochlorite ion (OCl-), hypobromous acid (HOBr) in equilibrium with
hypobromite ion (OBr-), and hydrogen gas (H2) as a by-product. During the electro-chemical
process a small amount of caustic (OH-) is also produced, which is effectively neutralized
within the cell and causes no apparent increase in the pH of treated ballast water.
The measurable oxidant species present during chlorine-based water disinfection, and the
terminology used, is often a point of confusion. By industry standards and convention, all
chlorine present in a water sample, regardless of form, is referred to as Free Available
Chlorine (FAC). FAC includes Cl2, HOCl, and OCl-. When including chloramines, the term
Combined (or Total) Chlorine is used. Similarly, all bromine species present in a water
sample are referred to Free Available Bromine (FAB). When including bromamine the term
Combined (or Total) Bromine is used. The common factor in all of these chemical species is
that they are considered oxidants, and due to the difficulty in measuring each chemical
species individually in a complex water sample, the term Total Residual Oxidants (TRO) is
used to include all of these oxidants when present in a sample. To clarify:
Free Available Chlorine (FAC) = Cl2 + HOCl + OClCombined (or Total) Chlorine = FAC + chloramine
Free Available Bromine (FAB) = Br2 + HOBr + OBrCombined (or Total) Bromine = FAB + bromamine
Total Residual Oxidants (TRO) = FAC + chloramine + FAB + bromamine
Therefore, in this dossier, TRO is used to describe the total of all oxidants present in treated
water. The chemical methods used for analyzing TRO often state that the measurement is
calculated as mg Cl2/L. However, these methods include all of the oxidants present in a
water sample as mentioned above, not just Cl2.
Severn Trent De Nora classifies the substances associated with the BalPure® system using
the definitions of Active Substances, Relevant Chemicals, and Other Components as
provided in Procedure (G9) Methodology (23 May 2008) and presents information on each in
the sections below.
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2.2
Active Substances
2.2.1
Hypochlorous acid and hypobromous acid
To avoid storing Active Substances on board, the BalPure® system safely generates sodium
hypochlorite by electrolysis of seawater. Seawater is passed through electrolytic cells
(electrolyzers) where it is subjected to medium amperage, low voltage direct current. The
electrolytic solution generated by the BalPure® system will consist of a near equal mixture of
hypochlorous acid (HOCl) and hypochlorite ion (OCl-) at the pH of seawater (typical range
of 7.5-8.4). As discussed above in section 2.1, the combination of Cl2, HOCl, and OCl- is
commonly referred to as free available chlorine (FAC).
Because seawater also contains bromide ion, it is important to note that reactions similar to
those occurring with chloride ion can also be occurring with bromide ion in the electrolytic
cell. For example, bromide ion will form Br2. At the pH of seawater the electrolytic solution
generated by the BalPure® system will also consist of a mixture of hypobromous acid (HOBr)
and hypobromite ion (OBr-), with a slightly greater proportion of the mixture existing as HOBr.
As discussed in section 2.1, the combination of Br2, HOBr, and OBr- are commonly referred
to as free available bromine (FAB).
In the solution generated, hypochlorous acid (HOCl) in equilibrium with hypochlorite ion
(OCl-) and hypobromous acid (HOBr) in equilibrium with hypobromite ion (OBr-) are the
actual disinfecting agents. In this dossier, these Active Substances are considered together
and referenced as Total Residual Oxidants (TRO as Cl2).
Details on the primary cell reactions occurring in the electro-chemical generation process in
seawater and the effect of pH on the distribution of chemical species formed were presented
in STDN's application dossier for Basic Approval (MEPC 60/2/9, section 2.2.1).
2.3
Relevant Chemicals
Disinfection of water with chlorine-based disinfectants can result in the formation of
disinfection by-products (DBPs). Due to the neutralization step, the Relevant Chemical
sodium bisulfite may also be present in ballast water discharge. Data on the substances that
had been analysed during initial pilot studies were presented in STDN's application dossier
for Basic Approval (MEPC 60/2/9). During land-based testing of the BalPure® system at
NIOZ the same substances, along with additional DBPs were evaluated. The substances
that were analysed for and presented in the Basic Approval dossier, and the substances
evaluated for Final Approval are summarized in the columns below. Substances denoted
with an "*" are those with a measurable concentration in samples from land-based testing.
Substances with a measurable concentration in treated/neutralized ballast water are
presented in this dossier. Substances with no measurable concentration (e.g., chlorate,
bromate) are not considered further in this dossier.
Basic Approval
Final Approval
THMs
THMs
Chloroform
Bromoform
Dibromochloromethane
Dichlorobromomethane
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Chloroform
Bromoform*
Dibromochloromethane*
Dichlorobromomethane*
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HAAs
HAAs
Monochloroacetic acid
Dichloroacetic acid
Trichloroacetic acid
Monobromoacetic acid
Dibromoacetic acid
Bromochloroacetic acid
Monochloroacetic acid*
Dichloroacetic acid*
Trichloroacetic acid
Monobromoacetic acid*
Dibromoacetic acid*
Tribromoacetic acid*
Bromochloroacetic acid*
Dibromochloroacetic acid*
Dichlorobromoacetic acid
Other Substances
Other Substances
Bromate
2,4,6-Tribromophenol*
Monobromoacetonitrile
Chlorate
Bromate
Sodium Bisulfite*
Sodium Bisulfate*
For the treated/neutralized ballast water samples evaluated during land-based testing,
chemical analysis was performed by Eurofins/Analytico (The Netherlands) and NovaChem
Laboratories (USA). The Relevant Chemicals are discussed in more detail in the following
sections.
Additionally, during the electrolysis process hydrogen gas is produced. For this reason,
hydrogen gas is considered as a Relevant Chemical and is discussed in more detail in
section 2.3.4.
Table 1 provides a summary of the substances potentially associated with the BalPure®
system.
Table 1: Overview of Chemical Identification
Substance
(IUPAC Name)
Identification
Numbers
Chemical
Formula
Structural
Formula
Hypochlorous acid
(Sodium Hypochlorite)
Active Substances in Ballast Water
CAS # 7681HOCl
52-9
Hypobromous acid
(Sodium Hypobromite)
CAS # 1382496-9
HOBr
Molecular
Weight
Dose/Classification
in Treated Ballast
Water
52.46
<15 mg/L TRO as Cl2
96.91
<15 mg/L TRO as Cl2
Relevant Chemicals
Bromate (as sodium
bromate)
CAS # 778938-0
NaBrO3
150.89
By-product
Chlorate
CAS # 1486668-3
ClO3-
83.451
By-product
2.016
By-product
119.947
By-product
Hydrogen
Monobromoacetonitrile
I:\MEPC\61\2-9.doc
CAS # 133-740
CAS # 590-170
H2
C2H2BrN
H---H
MEPC 61/2/9
Annex, page 11
Substance
(IUPAC Name)
Chemical
Formula
CAS # 118-796
C6H3Br3O
330.80
By-product
Dibromochloromethane
CAS # 124-481
CHBr2Cl
208.29
By-product
Dichlorobromomethane
CAS # 75-27-4
CHBrCl2
163.8
By-product
Tribromomethane
(bromoform)
CAS # 75-25-2
CHBr3
252.77
By-product
Trichloromethane
(chloroform)
CAS # 67-66-3
CHCl3
119.38
By-product
C2H2BrClO2
173.39
By-product
2,4,6-Tribromophenol
Structural
Formula
Molecular
Weight
Dose/Classification
in Treated Ballast
Water
Identification
Numbers
THMs
HAAs
Bromochloroacetic acid
CAS # 558996-8
Monochloroacetic acid
CAS # 79-11-8
C2H3ClO2
94.50
By-product
Dibromoacetic acid
CAS # 631-641
Br2CHCOOH
217.84
By-product
Dichloroacetic acid
CAS # 79-43-6
CHCl2COOH
128.9
By-product
Dibromochloroacetic
acid
CAS # 527895-5
C2HBr2ClO2
252.29
By-product
Dichlorobromoacetic
acid
CAS # 7113314-7
C2HBrCl2O2
207.84
By-product
Trichloroacetic acid
CAS # 76-03-9
CCl3COOH
163.4
By-product
Tribromoacetic acid
CAS # 75-96-7
C2HBr3O2
296.74
By-product
Monobromoacetic acid
CAS # 79-08-3
C2H3BrO2
138.95
By-product
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 12
Substance
(IUPAC Name)
Identification
Numbers
Chemical
Formula
Structural
Formula
Molecular
Weight
Dose/Classification
in Treated Ballast
Water
Other Chemicals
Sodium Bisulfate
CAS # 768138-1
HNaO4S
120.06
By-product
Sodium Bisulfite
CAS # 763190-5
NaHSO3
104.06
Neutralizing agent
2.3.1
Trihalomethanes (THMs) and haloacetic acids (HAAs)
During the disinfection process, reactions with organic materials present in water may result in
the formation of THMs and HAAs. The amount of THMs and/or HAAs formed as DBPs will
vary depending on water quality. The following THMs had measurable concentrations in
treated ballast water from the land-based test set-up: dichlorobromomethane (DCBM),
dibromochloromethane (DBCM), and bromoform. The data is presented in section 11.3,
Tables 22 and 23. Bromoform was also present at low levels in untreated (control) water, and
has been documented to occur naturally in seawater as it is produced by various algal species
(HSDB/TOXNET Tribromomethane, 2009; Goodwin et al., 1997; Ohsawa et al., 2001).
The following HAAs had measurable concentrations in treated ballast water from the
land-based test set-up: bromochloroacetic acid (BCAA), monochloroacetic acid (MCAA),
dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), dibromochloroacetic acid
(DBCAA), tribromoacetic acid (TBAA), and dibromoacetic acid (DBAA). The data is
presented in section 11.3, Tables 22 and 23.
2.3.2
2,4,6-Tribromophenol
2,4,6-Tribromophenol (TBP) did not have measurable concentrations (<0.1 µg/L detection
limit) in ballast water discharge from the high salinity test cycles. 2,4,6-TBP was detected at
low levels (maximum = 1.3 µg/L) in ballast water discharge from the low salinity test cycles
(section 11.3, Tables 22 and 23). 2,4,6-TBP was also detected in the untreated (control)
samples at the same, or higher, concentrations. 2,4,6-TBP has been documented to occur in
natural environments, either as a pollutant from anthropogenic sources (wood industry,
antifungal use) or from natural production by marine benthic organisms (OECD SIDS, 2003).
As presented in Table 4 below, the lowest chronic effect concentration identified
for 2,4,6-TBP is 0.10 mg/L (Daphnia magna). The 2,4,6-TBP concentration measured in
ballast water discharge is well below this effect concentration in both high and low salinity
test waters. Therefore, 2,4,6-TBP is not considered to be present at concentrations of
environmental concern in ballast water discharge. However, because 2,4,6-TBP did have
measurable concentrations in the low salinity tests, data to allow for a full risk assessment is
included in this dossier. 2,4,6-TBP was also included in the hydrodynamic modelling
evaluation to verify low potential aquatic environmental risk.
2.3.3
Bromate, chlorate and monobromoacetonitrile
The presence of bromate ions in treated ballast water was evaluated during land-based
testing at NIOZ and concentrations were not measurable (<10 µg/L detection limit)
(Tables 22 and 23). Further, the lowest acute aquatic toxicity effect concentration located for
bromate is 13.6 mg/L (Glenodinium halli) and the lowest chronic effect concentration located
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 13
is 16 mg/L (Thalassiosira pseudonana) (Tables 2 and 4, respectively). As bromate in ballast
water discharge is non-detectable and well below these effect concentrations, it is not
present at environmentally relevant concentrations. As such, bromate was not included in
the hydrodynamic modelling assessment and further data on bromate are not considered in
this dossier for Final Approval.
Chlorate was not an anticipated DBP but was analysed for verification. Samples from the
land-based test set-up demonstrated that chlorate was not present in ballast water discharge
in measurable concentrations (<50 µg/L detection limit) (Tables 22 and 23). Therefore,
chlorate is not addressed further in this dossier.
Monobromoacetonitrile was also a DBP evaluated in ballast water discharge samples from the
land-based test set-up at NIOZ. Concentrations in both low and high salinity test cycles were
not measurable (<1.0 µg/L or <10.0 µg/L detection limits). Therefore, monobromoacetonitrile is
not addressed further in this dossier.
2.3.4
Hydrogen gas
Hydrogen (H2) is formed as a by-product of seawater electrolysis. Due to the explosive
properties of hydrogen gas, allowing it to accumulate in the ballast tanks would create an
unsafe situation. Therefore, the hydrogen produced during the electro-chlorination process
is separated immediately upon exiting from the electrolytic cell using a patented cyclone
separation device and is not allowed to enter the ballast water piping. The separated
hydrogen gas is diluted to less than 1% hydrogen by forced air blowers and vented to the
atmosphere outside of the ship. The lower explosive limit (LEL) for hydrogen is 4% and the
operating limitations of the system provide a four-fold safety factor.
Relevant information pertaining to potential risks associated with hydrogen gas was provided
in STDN's application dossier for Basic Approval (MEPC 60/2/9). The GESAMP-BWWG
considered the assessment and safety measures presented in Basic Approval with regard to
H2 acceptable (MEPC 60/2/16, annex 7, sections 3.2.5 and 3.3.2).
2.4
Other chemicals
2.4.1
Sodium bisulfite and sodium bisulfate
During discharge of treated water (deballasting), sodium bisulfite (NaHSO3) is injected into
the ballast water discharge line to neutralize residual oxidants that may be present. The
bisulfite chemically reduces any free chlorine and/or hypochlorous acid to chloride ion, and
any free bromine and/or hypobromous acid to bromide ion. During land-based testing the
highest residual sodium bisulfite concentration measured in the whole effluent after injection
was 8.0 mg/L. Since the lowest sodium bisulfite LC50 located was 81 mg/L (Daphnia magna)
(Table 2), which is significantly higher than the highest residual sodium bisulfite measured in
ballast water discharge (8.0 mg/L), aquatic environmental risks would not be expected.
Further, sodium bisulfite does not bioaccumulate, is highly soluble in water, and not
expected to adsorb to sediments. However, to ensure that sodium bisulfite that may be
present in neutralized discharge does not present environmental risk, data to allow for a full
risk assessment was presented in STDN's application dossier for Basic Approval
(MEPC 60/2/9) and is evaluated further in this Final Approval dossier. Sodium bisulfite was
also included in the hydrodynamic modelling evaluation.
When sodium bisulfite reduces the chlorine and/or bromine species present as residual
oxidants in treated water, bisulfate ion can be formed. Bisulfate ion dissociates into sulfate and
hydrogen ions. Because the pKa for the bisulfate ion/sulfate ion equilibrium is approximately 2,
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 14
bisulfate ion that is formed during the neutralization step is expected to be in the form of sulfate
ion. Natural seawater typically contains approximately 3 g/L (3,000 mg/L) of sulfate ion.
Sodium bisulfate (as sulfate ion) was measured in samples collected from the land-based
test set-up to verify that the neutralizing agent does not cause a significant increase in the
level of sulfate ion present. The data show that the concentrations of sulfate ion in
neutralized ballast water compared to untreated (control) water is not significantly different.
The data are presented in section 11.3, Tables 22 and 23. Sulfate is not considered to pose
unacceptable environmental risks and is not evaluated further in this dossier. Based on the
GESAMP-BWWG report (section 3.1.1.4), this approach is accepted by the Group.
3
DATA ON EFFECTS ON AQUATIC PLANTS, INVERTEBRATES AND FISH, AND
OTHER BIOTA, INCLUDING SENSITIVE AND REPRESENTATIVE ORGANISMS
(G9: 4.2.1.1)
A literature search was conducted to locate existing aquatic ecotoxicity data for the
substances associated with the BalPure® system. The data summarized in Tables 2 and 4
present the acute and chronic toxicity data that was identified. A complete base-set for fish,
crustaceans, and algae was not located for all substances and in some cases the data do not
meet validity criteria. However, the data has been provided as supporting information and is
discussed in relation to the Predicted No Effect Concentration (PNEC) derivation in
section 11.9.
Tables 3 and 5 summarize acute and chronic ecotoxicity data on whole effluent from
land-based testing studies of the BalPure® system. Toxicity testing was done in conjunction
with studies performed at the Royal Netherlands Institute for Sea Research (NIOZ), Texel
(the Netherlands). Toxicity testing was performed by Grontmij/AquaSense (the Netherlands)
and Chemex Environmental International Ltd. (UK). Toxicity tests were conducted with six
taxonomic groups including bacteria, algae, crustaceans, rotifers, mollusks and fish in two
water types, i.e. brackish water (low salinity) and marine water (high salinity). The samples
for ecotoxicity testing were collected directly from the discharge pipe on Day 1 and on Day 5
after ballast water treatment and neutralization. Samples for analysis were stored in proper
sample containers at 4°C and transported to the designated laboratory within 24 hours of
collection. Analysis of the samples occurred within the time specified under standard
laboratory procedures. All tests were performed according to laboratory protocols based on
internationally recognized ISO, OECD, ASTM, and Parcom/OSPAR guidelines. Further,
water quality data from the land-based test cycles at NIOZ are presented in section 11.2
"Evaluation of treated ballast water (Table 21)".
3.1
Acute aquatic ecotoxicity
The following table summarizes the data found in literature concerning acute aquatic
ecotoxicity for the substances associated with the BalPure® system. In some cases, data
could not be located for all three taxonomic groups (fish, crustaceans and algae). Literature
concerning acute aquatic toxicity for bromochloroacetic acid, dibromochloroacetic acid, and
tribromoacetic acid could not be located for fish, crustaceans or algae. Similar data gaps are
noted in other dossiers submitted for approval under Procedure (G9), suggesting that other
literature searches have had similar findings. However, when available, data for other
taxonomic groups (amphibians and ciliates) or alternative endpoints (LC100 or EC03) are
included as supporting information.
To complete the data set for sodium bisulfite, STDN commissioned a 96-hour growth study with
Skeletonema costatum (Nautilus Environmental, 2009) that investigated potential toxic effects for
several concentrations of sodium bisulfite. The study resulted in an EC50 of 224 mg/L.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 15
Table 2: Acute Aquatic Ecotoxicity Data
Substance
F
C
A
E(L)C50
mg/L
NOEC
mg/L
0.059
0.032
<0.1
0.143
0.062
0.075
N/A
N/A
N/A
N/A
N/A
N/A
F Oncorhynchus mykiss 96-h survival
0.032
N/A
C Americamysis bahia
7-d survival
0.144
N/A
A Porphyra yezoensis
10-d growth
1.4
N/A
A Porphyra yezoensis
10-d mortality
2.3
N/A
A Chlorella sorokiniana
18-h survival
1
N/A
Species
Test Type
Oncorhynchus mykiss
Daphnia magna
Natural phytoplankton
Menidia beryllina
Mysidopsis bahia
Dunaliella primolecta
15-d survival
48-h survival
47-h change in Chla
96-h survival
96-h survival
24-h growth
Active Substance
Am
Reference/
Comments
Ci
TRO as Cl2
(Fresh water)
TRO as Cl2
(Saltwater)
Hypochlorous
acid
Hypobromous
acid
Bromate
2,4,6Tribromophenol
F
C
A
F
C
A
Fisher et al. (1999)
Fisher et al. (1999)
Brooks and Liptak (1978)
Fisher et al. (1999)
Fisher et al. (1999)
Videau et al. (1979)
US EPA ECOTOX
(Thatcher, 1978)
Fisher et al. (1994)
US EPA ECOTOX
(Maruyama et al., 1988)
US EPA ECOTOX
(Maruyama et al., 1988)
US EPA ECOTOX
(Kott and Edlis, 1969)
Relevant Chemicals
96-h survival
30.8
N/A
24-h survival
176
N/A
A Glenodinium halli
13.6
N/A
Hutchinson et al. (1997)
F
F
F
C
C
1.5
6.25
1.1
2.2
0.26
N/A
N/A
N/A
N/A
N/A
OECD SIDS (2003)
OECD SIDS (2003)
OECD SIDS (2003)
OECD SIDS (2003)
OECD SIDS (2003)
0.76
N/A
OECD SIDS (2003)
1.1
N/A
OECD SIDS (2003)
1.6
N/A
OECD SIDS (2003)
F Morone saxatilis
Neomysis
C
awatschensis
A
A
A
Cell growth;
exposure period
not specified
96-h survival
Oryzias latipes
Pimephales promelas 96-h survival
96-h survival
Cyprinus carpio
48-h immobilization
Daphnia magna
48-h immobilization
Daphnia magna
Selenastrum
72-h biomass
capricornutum
Selenastrum
24-48-h growth
capricornutum
Selenastrum
24-72-h growth
capricornutum
Richardson et al. (1981)
US EPA ECOTOX
(Crecelius, 1979)
THMs
F Lepomis macrochirus
96-h survival
14
N/A
US EPA ECOTOX
(Anderson and Lusty, 1980)
F Cyprinus carpio
72-120-h egg
fertilization to hatch
97
N/A
Mattice et al. (1981)
C Artemia salina
24-h survival
30
N/A
US EPA ECOTOX
(Foster and Tullis, 1984)
Scenedesmus
subspicatus
Cyprinodon
F
variegates
48-h growth
950
N/A
Kuhn and Pattard (1990)
72-h survival
18
N/A
US EPA ECOTOX
(Heitmueller et al., 1981)
Chloroform
A
F Cyprinus carpio
72-120-h egg
fertilization to hatch
52.3
N/A
Mattice et al. (1981)
C Daphnia magna
48-h immobilization
46
N/A
US EPA ECOTOX
(LeBlanc, 1980)
Skeletonema
costatum
96-h growth
inhibition
72-120-h egg
fertilization to hatch
12.3
N/A
US EPA ECOTOX (1978)
34
N/A
Mattice et al. (1981)
650
N/A
US EPA ECOTOX
(Yoshioka et al., 1985)
Bromoform
A
Chlorodibromomethane
F Cyprinus carpio
Ci
I:\MEPC\61\2-9.doc
Tetrahymena
pyriformis
24-h growth
MEPC 61/2/9
Annex, page 16
Substance
F
C
A
E(L)C50
mg/L
NOEC
mg/L
72
N/A
Toussaint et al. (2001)
67.4
N/A
Mattice et al. (1981)
24-h growth
240
N/A
US EPA ECOTOX
(Yoshioka et al.,1985)
C Daphnia magna
24-h immobilization
106
N/A
C Nitocra spinipes
96-h survival
23
N/A
Am
96-h development
3560
N/A
F Pimephales promelas 96-h survival
2000
N/A
C Daphnia magna
2000
N/A
A Chlorella pyrenoidosa 72-h growth
N/A
500
F Pimephales promelas 24-h survival
160
N/A
F Pimephales promelas 48-h survival
107
N/A
F Pimephales promelas 72-h survival
81
N/A
F Pimephales promelas 96-h survival
69
N/A
Species
Test Type
Am
Reference/
Comments
Ci
F Oryzias latipes
Dichlorobromomethane
F Cyprinus carpio
Ci
Tetrahymena
pyriformis
96 h survival
72-120-h egg
fertilization to hatch
HAAs
Dichloroacetic
acid
Trichloroacetic
acid
Dibromoacetic
acid
Xenopus laevis
48-h immobilization
Dibromochloroacetic acid
Tribromoacetic
acid
Bromochloroacetic acid
Monobromoacetic acid
No data found in literature
No data found in literature
No data found in literature
F Cyprinus carpio
5-h survival
222
N/A
C Daphnia magna
24-h survival
34
N/A
48-h survival
0.34
N/A
A
Monochloroacetic acid
US EPA ECOTOX
(Trenel and Kuhn, 1982)
US EPA ECOTOX
(Linden et al, 1979)
US EPA ECOTOX
(Fort et al., 1993)
US EPA ECOTOX
(Dennis et al., 1979)
US EPA ECOTOX
(Dennis et al., 1979)
US EPA ECOTOX
(Huang and Gloyna, 1968)
US EPA ECOTOX
(Mayes et al., 1985)
US EPA ECOTOX
(Mayes et al., 1985)
US EPA ECOTOX
(Mayes et al., 1985)
US EPA ECOTOX
(Mayes et al., 1985)
Scenedesmus
subspicatus
F Cyprinus carpio
28-h survival
C Daphnia magna
Scenedesmus
A
subspicatus
Scenedesmus
A
subspicatus
48-h mobility
191
(LC100)
96
48-h growth
48-h growth
US EPA ECOTOX
(Loeb and Kelly, 1963)
US EPA ECOTOX
(Kuhn, 1988)
Kuhn and Pattard (1990)
N/A
US EPA ECOTOX
(Loeb and Kelly, 1963)
Kuhn and Pattard (1990)
0.028
N/A
Kuhn and Pattard (1990)
0.07
N/A
Kuhn and Pattard (1990)
N/A
Other Chemicals
F Carassius spp.
96-h survival
100
N/A
F Gambusia affinis
96-h survival
240
N/A
C Daphnia magna
96-h survival
102
N/A
C Daphnia magna
50-h survival
81
N/A
C Daphnia magna
24-h survival
171
N/A
Skeletonema
costatum
96-h growth
224
128
Sodium bisulfite
A
MSDS Solvay Chemicals
(2007)
US EPA ECOTOX
(Wallen et al., 1957)
US EPA ECOTOX
(Freeman and Fowler, 1953)
US EPA ECOTOX
(Dowden and Bennett, 1965)
US EPA ECOTOX
(Dowden and Bennett, 1965)
Nautilus Environmental,
2009
F = fish, C = crustacean, A = algae, Am = amphibian, Ci = ciliate, N/A = not applicable.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 17
Table 3 summarizes acute aquatic toxicity testing results for treated discharge samples,
post-neutralization, from the BalPure® system. Toxicity tests were conducted with six taxonomic
groups including bacteria, algae, crustaceans, rotifers, mollusks and fish in two water types:
brackish water (low salinity) and marine water (high salinity). The samples were collected for
toxicity testing on Day 1 and Day 5 after ballast water treatment and neutralization. Toxicity
was indicated in one acute test with Acartia tonsa one day after BalPure® treatment
(NOEC of 18%). Discussion of the whole effluent toxicity data is located in section 11.4.
Table 3: Acute Aquatic Ecotoxicity Data - Land-based Testing
F
C
Substance A
MB
R
Species
C
Acartia tonsa
M
Crassostrea
gigas
B
Vibrio fischeri
A
Phaeodactylum
tricornutum
R
Brachionus
plicatilis
Scophthalmus
maximus
®
BalPure
Treatment
Dose:
14.83 mg/L
(ave.)
F
C
Acartia tonsa
M
Crassostrea
gigas
B
Vibrio fischeri
A
Phaeodactylum
tricornutum
R
Brachionus
plicatilis
Scophthalmus
maximus
®
BalPure
Treatment
Dose:
13.17 mg/L
(ave.)
F
Test Type
Days
E(L)C50 NOEC
after
%
%
treatment sample sample
Low Salinity (23.68 PSU)
1
>100
48h mobility
(ISO 14669)
5
>100
48h larval
1
>100
development
5
>100
(ASTM E724)
30m inhibition of
1
>90*
light emission
5
>90*
(ISO 11348-3)
72h growth
1
>100
inhibition
5
>100
(ISO 10253)
1
>100
24h survival
(MircoBioTests Inc.)
5
>100
1
>100
96h survival
(OECD 203)
5
>100
High Salinity (33.90 PSU)
1
>100
48h mobility
(ISO 14669)
5
>100
48h larval
1
>100
development
5
>100
(ASTM E724)
30m inhibition of
1
>90*
light emission
5
>90*
(ISO 11348-3)
72h growth
1
>100
inhibition
5
>100
(ISO 10253)
1
>100
24h survival
(MircoBioTests Inc.)
5
>100
1
>100
96h survival
(OECD 203)
5
>100
Reference/
Comments
18
100
100
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
N/R
Grontmij|AquaSense, 2009
N/R
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
100
100
100
100
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
100
100
100
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
N/D
Grontmij|AquaSense, 2009
N/R
Grontmij|AquaSense, 2009
N/R
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
100
100
100
100
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
F = fish, C = crustacean, A = algae, M = mollusk, B = bacteria, R = rotifer.
N/D = not determined; N/R = not reported.
*Maximum tested concentration = 90% vol. of sample.
3.2
Chronic aquatic ecotoxicity
Table 4 summarizes the data found in literature concerning chronic aquatic toxicity for the
substances associated with the BalPure® system. Literature concerning chronic aquatic
toxicity for several HAAs could not be located to compile a complete data set (fish,
crustaceans, algae). Similar data gaps are also noted in other dossiers submitted for
approval under Procedure (G9), suggesting that other literature searches have had similar
findings. However, if available, data using alternative endpoints (EC03) is included as
supporting information.
I:\MEPC\61\2-9.doc
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Annex, page 18
Table 4: Overview of Chronic Aquatic Ecotoxicity Data
Substance
F
C
A
Species
Test Type
E(L)C50 NOEC
mg/L mg/L
Reference/
Comments
Active Substance
TRO as Cl2
(Fresh water)
TRO as Cl2
(Saltwater)
Hypochlorous
acid
F Ictalurus punctatus
Gammarus
C
pseudolimnaeus
134-d growth
N/A
0.005 Hermanutz et al. (1990)
70-d fecundity
N/A
0.012 Arthur et al. (1975)
A Natural algae
N/A
0.079 Pratt et al. (1988)
F
C
N/A
N/A
0.04 Goodman et al. (1983)
0.079 Saroglia and Scarano (1979)
N/A
0.001 Sanders et al. (1981)
N/A
0.101
A
F
C
24-d inhibition of
biomass
32-d egg to post-hatch
Menidia peninsula
Panaeus kerathurus 7-d growth/molting
Natural
21-d reduction in cell
phytoplankton
density
Oncorhynchus
23-d survival
kisutch
Americamysis bahia 7-d reproduction
N/A
US EPA ECOTOX
(Holland et al., 1960)
0.048 Fisher et al. (1994)
Hypobromous
acid
No data found in literature
Relevant Chemicals
10-d survival
92.6
--
Richardson et al. (1981)
10-d survival
278.6
--
Richardson et al. (1981)
7-d growth inhibition
16
--
8-d survival
4.5
N/A
21-d reproduction rate
N/A
0.10
US EPA ECOTOX
(Erickson and Freeman, 1978)
US EPA ECOTOX
(Phipps et al., 1981)
OECD SIDS (2003)
72-h biomass
N/A
0.22
OECD SIDS (2003)
24-72-h growth
N/A
1.0
OECD SIDS (2003)
9- month growth
N/A
1.5
C Daphnia magna
21-d reproduction
N/A
13
Toussaint et al. (2001)
US EPA ECOTOX
(Kuhn et al., 1988)
Skeletonema
costatum
Cyprinodon
F
variegates
Pseudokirchneriella
A
subcapitata
5-d reduction in cell
volume
477
216
Cowgill et al. (1989)
28d- growth
N/A
8.5
US EPA ECOTOX
(Ward et al., 1981)
96-h biochemistry
change
N/A
38.6
U.S. EPA ECOTOX (1978)
F Morone saxatilis
Leiostomus
F
Bromate
zanthurus
Thalassiosira
A
pseudonana
Pimephales
F
promelas
C Daphnia magna
2,4,6Selenastrum
Tribromophenol A
capricornutum
Selenastrum
A
capricornutum
THMs
F Oryzias latipes
Chloroform
A
Bromoform
Dichlorobromomethane
Chlorodibromomethane
HAAs
Dichloroacetic
Scenedesmus
A
acid
subspicatus
Dibromochloroacetic acid
Dibromoacetic
acid
Tribromoacetic
acid
Scenedesmus
A
quadricauda
Trichloroacetic
acid
A Chlorella vulgaris
Bromochloroacetic acid
I:\MEPC\61\2-9.doc
No data found in literature
No data found in literature
7-d cell proliferation
1485
(EC03)
N/A
US EPA ECOTOX
(Trenel and Kuhn, 1982)
No data found in literature
No data found in literature
No data found in literature
7-d growth threshold
N/A
200
OECD SIDS (2000)
4d-population change
N/A
100
US EPA ECOTOX
(Garten, 1990)
No data found in literature
MEPC 61/2/9
Annex, page 19
F
C
A
Substance
Monobromoacetic acid
Species
Test Type
Reference/
Comments
US EPA ECOTOX
(Kuhn, 1988)
US EPA ECOTOX
(Kuehn et al, 1989)
C Daphnia magna
21d-NOEC
N/A
3.2
C Daphnia magna
21d-NOEC on
reproduction
N/A
1.6
3d-population change
N/A
1.4
Kuhn and Pattard (1990)
21d-reproduction
change
N/A
32
Kuhn and Pattard (1990)
0.13
(EC03)
N/A
US EPA ECOTOX
(Trenel and Kuhn, 1982)
A
Scenedesmus
subspicatus
C Daphnia magna
Monochloroacetic acid
E(L)C50 NOEC
mg/L mg/L
A
Scenedesmus
subspicatus
7d-histology
Other Chemicals
Sodium
bisulfite
No data found in literature
F = fish, C = crustacean, A = algae, N/A = not applicable.
Results for chronic whole effluent toxicity (WET) testing of treated/neutralized ballast water
discharge are summarized in Table 5 below and discussed further in section 11 "Evaluation
of treated ballast water". Samples were drawn from the land-based test set-up and no
chronic toxicity was observed for any species tested. The highest concentration with no
observed effect (NOEC) was 100 per cent sample (Grontmij|AquaSense, 2009). As agreed
upon with the German Administration, chronic testing was performed only for organisms that
had effects noted during acute testing. As acute effects were only observed during one of
four acute tests with Acartia tonsa (NOEC 18%), STDN also performed chronic (sub-lethal)
testing for fish. The data indicate that no chronic effects were noted for either species tested.
Table 5: Chronic Aquatic Ecotoxicity Data – Land-based Testing
Substance
BalPure®
Treatment
Dose:
14.83 mg/L
(ave.)
BalPure®
Treatment
Dose:
13.17 mg/L
(ave.)
F
C
Species
C
Acartia tonsa
F
Scophthalmus
maximus
C
Acartia tonsa
F
Scophthalmus
maximus
Days
E(L)C50
%
after
treatment sample
Low Salinity (23.68 PSU)
1
N/D
30d repro./devel.
(ASTM STP 667)
5
N/D
1
>100
48h develop
(PARCOM 1994)
5
>100
Test Type
High Salinity (33.90 PSU)
1
N/D
30d repro./devel.
(ASTM STP 667)
5
N/D
1
>100
48h develop
(PARCOM 1994)
5
>100
NOEC
%
sample
Reference/
Comments
100
100
100
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
100
100
N/D
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
Grontmij|AquaSense, 2009
100
Grontmij|AquaSense, 2009
F = fish, C = crustacean, N/D = not determined.
3.3
Endocrine disruption
Endocrine disrupting chemicals (EDCs) are defined as exogenous substances that cause
adverse effects in an organism or its progeny, consequent to changes in endocrine functions.
In a recently conducted study to investigate whether chlorinated by-products formed through
waste water disinfection were estrogenic, no relationship was found between the formation of
THMs and estrogenic activity (Schiliro, 2009). In fact, chlorination of surface water and
effluents was found to decrease estrogenic activity, which is thought to be due to the oxidation
effects of chlorine (Lee, 2004). A thorough review of the literature found no indications that
either of the Active Substances in the TRO as Cl2 (HOCl/HOBr) or the chemically more
complex THMs/HAAs were EDCs.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 20
Brominated phenols have been shown to cause a significant effect on the Ca2+ homeostasis
in endocrine cells by causing an intracellular increase in Ca2+ (Hassenklöver et al., 2006).
At concentrations of 300 µM or higher this effect may suggest a link to endocrine disruption
by 2,4,6-tribromophenol (TBP). Due to the low concentration of 2,4,6-TBP (maximum
concentration of 1.3 µg/L) (Tables 22 and 23) detected in treated ballast water, and the
limited routes of exposure in environmental waters, no endocrine effects would be expected
as a result of treated ballast water discharge.
3.4
Sediment toxicity
The sediment toxicity of a chemical is a function of the ability of the chemical to be adsorbed
to sediment as well as its persistence and toxicity. The organic carbon partition coefficient
(Koc) is a measure of the tendency of an organic substance to be adsorbed by soil or
sediment. STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4)
provided data for THMs/HAAs measured in previous studies of the BalPure® system. During
land-based testing, additional DBPs were analysed and three were found in measurable
concentrations. Data for these three additional substances is provided below.
The Koc for 2,4,6-TBP (1,186 L/kg) indicates moderate partitioning into sediment. When
2,4,6-TBP is released to water, 93% is expected to stay in the water compartment and 7% is
transported to the sediment compartment (OECD SIDS, 2003). 2,4,6-Tribromophenol is
reported to dehalogenate rapidly in anaerobic sediments, with a reported half-life of
approximately 4 days (CICADS 66, 2005). This is much more rapid than the sediment
persistence criteria of 180 days in marine sediment and 120 days in fresh water sediment
(Table 19 and the Methodology for information gathering and the conduct work of the
GESAMP-BWWG (Methodology), section 6.1.4). Considering the low concentration of
2,4,6-TBP (maximum = 1.3 µg/L) in ballast water discharge, a moderate potential for
sediment adsorption, and the rapid sediment degradation, no effects on sediment are
expected as a result of the BalPure® system.
Based on the low Koc values for dibromochloroacetic acid (DBCAA) and tribromoacetic acid
(TBAA) (3.23 L/kg and 5.3 L/kg, respectively), these substances are not expected to partition
into sediment. Therefore, no sediment toxicity impacts are anticipated as a result of
BalPure® ballast water discharge.
Table 6: Koc Values for Relevant Chemicals
Substance
2,4,6-Tribromophenol (TBP)
HAAs
Dibromochloroacetic acid (DBCAA)
Tribromoacetic acid (TBAA)
3.5
Koc (L/kg)
Relevant Chemicals
1,186
3.23
5.3
Reference/Comments
OECD SIDS (2003)
EPI Suite v4.0
HSDB/TOXNET (2009)
Bioavailability/biomagnification/bioconcentration
The bioconcentration factor (BCF) is the concentration of a particular chemical in a tissue per
concentration of chemical in water (reported as L/kg). This physical property characterizes
the accumulation of pollutants through chemical partitioning from the aqueous phase into an
organic phase, such as fish or other aquatic organism tissues. The BCF is the best measure
of bioavailability, biomagnification, and bioconcentration. Typical BCFs for organic chemicals
in fish and most aquatic invertebrates are in the 500-1,000 L/kg range. STDN's application
dossier for Basic Approval (MEPC 60/2/9, section 3.5) provided data for THMs/HAAs
measured in previous studies of the BalPure® system. During land-based testing, additional
DBPs were analysed and three were found in measurable concentrations. Data for these
three additional substances is provided below.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 21
The BCFs summarized in Table 7 below are all well below 2,000 L/kg (Methodology,
section 6.1.4 and Table 19 of this document), indicating that they are unlikely to
bioconcentrate/bioaccumulate in aquatic organisms or present a food chain risk.
Table 7: BCFs for Relevant Chemicals
Substance
2,4,6-Tribromophenol (TBP)
HAAs
Dibromochloroacetic acid (DBCAA)
Tribromoacetic acid (TBAA)
3.6
BCF (L/kg)
Relevant Chemicals
83 - 513
3.16
0.63
Reference/Comments
HSDB/TOXNET (2009)
EPI Suite v4.0
HSDB/TOXNET (2009)
Food web/population effects
Population and food web effects can occur if substances have properties that tend to
bioaccumulate and/or persist in the environment. Little biomagnification and persistence in
aquatic and mammalian food webs is anticipated from the Relevant Chemicals.
This conclusion is based on the low Koc values for DBCAA and TBAA. Additionally, the
BCFs for DBCAA and TBAA are well below 500 L/kg indicating that
bioconcentration/bioaccumulation is not expected to occur in aquatic organisms. Although
the Koc for 2,4,6-TBP indicates a moderate potential to be transported to the sediment
compartment, and a BCF range of 83-513 L/kg indicates moderate bioconcentration/
bioaccumulation potential, the concentration of 2,4,6-TBP measured in treated/neutralized
ballast water was very low (maximum = 1.3 µg/L). In one case, 2,4,6-TBP had higher
measurable concentration in the control than in the treated/neutralized ballast water sample
(Table 23). Therefore, no food web and/or population effects can be expected as a result of
these Relevant Chemicals in BalPure® ballast water discharge.
4
DATA ON MAMMALIAN TOXICITY (G9: 4.2.1.2)
STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided data for
DBPs measured during previous studies of the BalPure® system. During land-based testing
at NIOZ, additional DBPs were analysed for and three substances were found in measurable
concentrations. Mammalian toxicity data for these three additional substances is provided in
Tables 8 to 16 below. Information on all previously measured substances was presented in
the Basic Approval dossier (MEPC 60/2/9).
In the mammalian toxicity studies reviewed, the chemicals were tested for various exposure
routes (oral, dermal, etc.) and/or chemical forms, which do not necessarily reflect the actual
potential exposure routes or chemical forms associated with the BalPure® system. In some
cases, data could not be located in available literature.
4.1
Acute mammalian toxicity
Table 8: Acute Mammalian Toxicity Data
Substance
Exposure Route
Species
Value
Range
Relevant Chemicals
a. Acute Oral LD50
a. Rat
a. >5000 mg/kg
2,4,6-Tribromophenol (TBP) b. Inhalation LC50
b. Rat
b. >50 mg/L/4hr
c. Acute Dermal LD50
c. Rabbit c. >8000 mg/kg
HAAs
Dibromochloroacetic acid
Limited toxicology data available.
--(DBCAA)
Tribromoacetic acid (TBAA)
I:\MEPC\61\2-9.doc
Limited toxicology data available.
--
--
Reference/
Comments
a. CICADS 66 (2005)
b. CICADS 66 (2005)
c. CICADS 66 (2005)
Richardson et al. (2007)
Richardson et al. (2007)
MEPC 61/2/9
Annex, page 22
4.2
Effects on skin and eye
Table 9: Effects on Skin and Eye
Substance
Skin
Eye
Relevant Chemicals
2,4,6-Tribromophenol
Moderately
Not irritating to rabbits
(TBP)
irritating to rabbits
HAAs
May be harmful if
Dibromochloroacetic
absorbed through skin;
Causes eye burns
acid (DBCAA)
causes skin burns
a) Corrosive; causes
a) Destructive to
burning sensation, and is tissue of the
Tribromoacetic acid
destructive to tissue of
mucous
(TBAA)
mucous membranes of
membranes of
skin
eyes
4.3
Sensitization
Reference/
Comments
Skin sensitizer in
guinea-pigs
CICADS 66 (2005)
No data found in
literature
Sigma Aldrich MSDS
(2009)
b) No sensitizing
effect known.
a) HSDB/TOXNET
(2009)
b) Alfa Aesar MSDS
(2009)
Repeated-dose toxicity
Table 10: Repeated-dose Toxicity
Substance
Exposure Route
Species
Value Range
Reference/
Comments
Relevant Chemicals
2,4,6-Tribromophenol
(TBP)
Oral, 48 day subchronic
reproduction/developmental
HAAs
Dibromochloroacetic
acid (DBCAA)
Tribromoacetic acid
(TBAA)
Limited toxicology data
available.
Limited toxicology data
available.
4.4
Rat
NOAEL 100
mg/kg body
weight/day
CICADS 66 (2005)
--
--
Richardson et al. (2007)
--
--
Richardson et al. (2007)
Chronic mammalian toxicity
Table 11: Chronic Mammalian Toxicity
Substance
2,4,6-Tribromophenol
(TBP)
HAAs
Dibromochloroacetic
acid (DBCAA)
Tribromoacetic acid
(TBAA)
I:\MEPC\61\2-9.doc
Exposure Route
Species
Relevant Chemicals
No long term exposure
studies on brominated
-phenols were identified.
Value Range
--
--
--
--
--
--
--
Reference/
Comments
CICADS 66 (2005)
No data found in
literature
No data found in
literature
MEPC 61/2/9
Annex, page 23
4.5
Developmental and reproductive toxicity
Table 12: Summary of Developmental and Reproductive Toxicity Data
Substance
Exposure Route
Oral gavage, doses
2,4,6-Tribromophenol from 10- 3000
(TBP)
mg/kg/day, on
gestation days 6-15
Species
Reference/
Comments
Effects
Relevant Chemicals
No effect on fertility, growth, or survival
at doses of 200 mg/kg/d or less; Slight
Rats decrease in body weight and decrease
in number of viable fetuses in
1000 mg/kg/d; NOAEL 300 mg/kg/d
CICADS 66
(2005)
HAAs
Dibromochloroacetic
acid (DBCAA)
26- hour Embryo
exposure;
Concentrations
1500-2500 µM DBCAA
Mice
Tribromoacetic acid
(TBAA)
a) Oral, tribromoacetic
acid in drinking water,
14 days, doses up to
400 ppm TBAA
b) 24-26 hours Embryo
exposure;
Concentrations from
0-5,000 µM TBAA
Rats
4.6
≥1500 µM increased the number of
dysmorphic embryos with prosensephalic
hypoplasia and eye defects were observed; Hunter et al.
≥2000 µM caused heart dysmorphology (2006)
and abnormal yolk sac morphology;
≥2500 µM caused failure to develop
a) No effects on reproductive function,
as a general toxicant, or as reproductive a) NTP
toxicant in males
(1998)
b) ≥3,000 µM TBAA induced
malformation effects; nonclosure of the
cranial neural tube and reduction in
development of bulbus cordis
b) Hunter
et al.
(1996)
Carcinogenicity
Table 13: Summary of Data on Carcinogenicity
Substance
Carcinogen Classification
Description
Relevant Chemicals
a. Not classified by NTP
b. Not classified by IARC
2,4,6-Tribromophenol
c. No carcinogenicity studies
-(TBP)
on brominated phenols
were identified.
HAAs
Oral exposure in drinking water;
2 years; shown to induce tumours
Dibromochloroacetic a. Not classified by NTP
in the livers of mice; limited details
acid (DBCAA)
b. Not classified by IARC
on test doses; references c. and d.
identified DBCAA has cancer
potential and is currently under study
c. Likely to be weakly carcinogenic;
or carcinogenic toward a single
Tribromoacetic acid
a. Not classified by NTP
species/target at relatively high
(TBAA)
b. Not classified by IARC
doses based on structure-activity
relationship (SAR) analysis
I:\MEPC\61\2-9.doc
Reference/
Comments
a. NTP (2009)
b. IARC (2009)
c. CICADS 66 (2005)
a. NTP (2009)
b. IARC (2009)
c. Richardson et al.
(2007)
d. Woo et al. (2002)
a. NTP (2009)
b. IARC (2009)
c. Woo et al. (2002)
MEPC 61/2/9
Annex, page 24
4.7
Mutagenicity and genotoxicity
Table 14: Summary of Data on Mutagenicity and Genotoxicity
Substance
Study Results
Reference/
Comments
Relevant Chemicals
Tested in Salmonella/microsome preincubation assay with doses
0-333 µg/plate in Salmonella typhimurium strains TA98, TA100,
2,4,6-Tribromophenol TA1535, and TA1537 in presence and absence of
HSDB/TOXNET (2009)
(TBP)
Aroclor-induced rat/hamster liver S9; highest nonmutagenic test
dose = 100 µg/plate causing a slight clearing in background lawn
above this dose level
HAAs
Dibromochloroacetic
Limited mutagenicity / genotoxicity studies on DBCAA available. Richardson et al. (2007)
acid (DBCAA)
Studies show TBAA causes mutagenic and genotoxic responses
a. Nelson et al. (2001)
Tribromoacetic acid
in Salmonella typhimurium strain TA100 in a) fluctuation and
b. Giller et al. (1997)
(TBAA)
microsuspension assays and b) in SOS chromotest
4.8
Toxicokinetics
Table 15: Summary of Uptake, Absorption, and Excretion of Chemicals
Substance
2,4,6-Tribromophenol
(TBP)
Study Results
Reference/
Comments
Relevant Chemicals
After administration of a single oral dose (4.04-5.34 mg/kg) to rats
the substance was rapidly absorbed from gastro-intestinal tract;
OECD SIDS (2003)
77% excreted via urine, 2-14% eliminated in feces within 48 h;
blood t1/2 was 2.03 h
HAAs
Dibromochloroacetic
acid (DBCAA)
Tribromoacetic acid
(TBAA)
After administration of a single dose (25 µmol/kg) by iv rats,
plasma elimination of DBCAA was rapid with t1/2 of 1.6 h; dose
urinary recovery was 33%; Same dose given by gavage yielded
plasma elimination t1/2 of 4.59 h; 40-70% of total body clearance
due to metabolic clearance
After administration of a single dose (25 µmol/kg) by to rats,
elimination of TBAA was rapid with t1/2 of 46 min; dose urinary
recovery was 8%; Same dose given by gavage yielded plasma
elimination t1/2 of 2.11h; 40-70% of total body clearance due to
metabolic clearance
Saghir & Schultz
(2005)
Saghir & Schultz
(2005)
5
DATA ON ENVIRONMENTAL FATE AND EFFECT UNDER AEROBIC AND
ANAEROBIC CONDITIONS (G9: 4.2.1.3)
5.1
Modes of degradation (biotic; abiotic)
STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided
degradation data for DBPs measured during previous studies of the BalPure® system.
During land-based testing at NIOZ, additional DBPs were analysed and three substances
were found in measurable concentrations. Degradation data for these three additional
substances is provided in Table 16 below.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 25
Table 16: Fate and Mode of Degradation for Relevant Chemicals
Substance
2,4,6-Tribromophenol
(TBP)
Fate/Effect Under
Reference/
Aerobic/Anaerobic
Modes of Degradation
Comments
Conditions
Relevant Chemicals
Biotic: BOD 49% after 28 days in
Anaerobic: reported to
activated sludge; 82% degraded in 3-day
dehalogenate rapidly in
biodegradation test in river water.
CICADS 66
anaerobic sediments,
Abiotic: Stable in water and not hydrolyzed (2005)
half-life of approx. 4 days
regardless of pH; Direct photolysis by UV
(CICADS 66, 2005)
in air indicates a half life of 4.6 hours
HAAs
Dibromochloroacetic
acid (DBCAA)
Tribromoacetic acid
(TBAA)
5.2
Biotic and Abiotic: demonstrated in study
with and without microbial inhibitors in which
degradation occurred in both experiments.
Aerobic: Used as carbon
Biotic: microbial degradation
source by Pseudomonas
demonstrated (Hashimoto et al., 1998)
and Nocardia when
Abiotic: Atmospheric half-life = 30.9 days;
measured for halide
not expected to undergo hydrolysis or
release over 20 days (30ºC) susceptible to direct photolysis by UV
No data located.
Hashimoto et al.
(1998)
HSDB/TOXNET
(2009)
Bioaccumulation, partition coefficient, octanol/water partition coefficient
Based on the data presented for degradation in Table 16 above, the BCFs presented in Table 7,
and Koc values in Table 6, these additional substances associated with the STDN BalPure®
system have a low likelihood of bioaccumulation and partitioning to aquatic sediments.
5.3
Persistence and identification of the main metabolites in the relevant media
Higher tier simulation tests are not required; this section is not applicable.
5.4
Reaction with organic matter
The formation of disinfection by-products (DBPs) when using chlorine-based water disinfection
methods is well known. DBP formation is a result of disinfectant reactions with natural organic
matter, often measured as total organic carbon (TOC), which serves as the organic precursor
(IPCS, 2000). Two major classes of DBPs that are commonly formed in chlorine treated water
include THMs and HAAs (Westerhoff, et al., 2003). Both of these DBP classes have been
measured in water treated with the BalPure® system. Water quality (e.g., pH, temperature,
bromide level, TOC) and treatment conditions (e.g., hypochlorite dose, contact time, removal
of organic matter prior to treatment) influences the formation of DBPs as a result of organic
matter reactions. Further, the distribution of DBP species (up to four THM species, up to nine
HAA species) is affected by the amounts of TOC, bromide and chlorine present (IPCS, 2000).
Analysis to quantify DBP concentrations in ballast water discharge was conducted during
land-based testing of the BalPure® system at NIOZ in 2009. Different water types (brackish,
seawater) were treated/neutralized and then evaluated for DBPs. The data are presented in
section 11, Tables 22 and 23.
5.5
Potential physical effects on wildlife and benthic habitats
When evaluated using GESAMP Reports and Studies No. 64, the chemical and physical
properties of the Active Substances and Relevant Chemicals associated with the BalPure®
system as presented in STDN's application dossier for Basic Approval (MEPC 60/2/9,
Tables 17 to 21) and in Table 17 below indicate that physical effects on wildlife and benthic
habitats as described are not expected to occur.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 26
5.6
Potential residues in seafood
Chemicals measured in treated ballast water discharge may pose a threat to seafood
consumers only if they tend to bioaccumulate (within a trophic level, an increase in
concentration of a substance in tissues due to uptake from food and sediments) or
biomagnify (an increase in the concentration of a substance in the food web). The
bioaccumulation criteria per the Methodology (MEPC 58/2/7, annex 4) include an
octanol-water partition coefficient (Log Kow) of ≥3 or a bioconcentration factor (BCF) >2000.
With the exception of 2,4,6-tribromophenol, the chemicals presented in STDN's application
dossier for Basic Approval (MEPC 60/2/9) and identified in this risk assessment all have
Log Kow values less than 3. However, based on the discussion for 2,4,6-TBP in section 3.4
above, and the fact that the BCFs for all substances are less than 2000, the substances are
not expected to bioaccumulate, persist in the food web, or cause tainting of seafood.
6
PHYSICAL AND CHEMICAL PROPERTIES FOR THE ACTIVE SUBSTANCES,
RELEVANT CHEMICALS, AND TREATED BALLAST WATER (G9: 4.2.1.4)
STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided chemical
and physical property data for Active Substances and relevant DBPs measured in treated
ballast water during previous studies of the BalPure® system. The Basic Approval dossier
also presented the chemical and physical properties of treated ballast water. During
land-based testing at NIOZ, additional DBPs were analysed and three substances were
found in measurable concentrations. Available chemical property data for these three
additional substances is provided in Table 17 below.
Table 17: Physical and Chemical Properties of Relevant Chemicals
Physical/Chemical
Properties
2,4,6-Tribromophenol
Dibromochloroacetic
acid
Melting Point (ºC)
93.9 (CICADS 66, 2005)
151.68 (EPI Suite, 2009)
Boiling point (ºC)
Flammability
(flash point for liquids; ºC)
244 (CICADS 66, 2005)
263.59 (EPI Suite, 2009)
129-135 (HSDB/TOXNET,
2009)
245 (HSDB/TOXNET, 2009)
Not available
Not available
Not available
Not available
Not available
0.692 Pa
(EPI Suite, 2009)
3.73 x 10-2 Pa
(HSDB/TOXNET, 2009)
59 mg/L (25ºC) /
pka = 6.08
(CICADS 66, 2005)
2353 mg/L (25ºC)
(EPI Suite, 2009)
2.0 x 105 (25ºC) / pka = 0.72
(HSDB/TOXNET, 2009)
ORP of natural seawater
ORP of natural seawater
ORP of natural seawater
Not available
Not available
Not available
Not available
Not available
Not available
3
Density (20ºC; kg/m )
Vapour pressure/Vapour
density (air=1)
Water solubility (temp;
effect of pH; mg/L)/
Dissociation constant
(pKa)
Oxidation/Reduction
potential
Corrosivity to materials
Auto-ignition temperature
(ºC)
Explosive properties
Oxidizing properties
Surface tension
Viscosity (20ºC)
Thermal stability
Reactivity to container
material
Other knowns
I:\MEPC\61\2-9.doc
2550
(Alfa Aesar MSDS, 2009)
4.2 x 10-2 Pa
(CICADS 66, 2005)
Not explosive
(Alfa Aesar MSDS, 2009)
No available
Not available
Not available
Stable
Not stored;
produced in situ
None
Not available
Not available
Not available
Not available
Stable
Not stored;
Produced in situ
None
Tribromoacetic acid
Not explosive
(Alfa Aesar MSDS, 2009)
Not available
Not available
Not available
Stable
Not stored; produced in situ
None
MEPC 61/2/9
Annex, page 27
7
ANALYTICAL METHODS AT ENVIRONMENTALLY RELEVANT CONCENTRATIONS
(G9: 4.2.1.5)
7.1
Analysis of Total Residual Oxidants (TRO as Cl2)
TRO (as Cl2) is measured at two concentration ranges (high and low) using two different
analytical procedures. An iodometric titration procedure is used to measure higher range
TRO (as Cl2) in the product stream exiting the BalPure® unit. Concentrations are
typically 1,000 mg/L and this procedure is accepted by the American Water Works
Association (AWWA) for examination of water and waste water. The procedure is only used
if needed to perform diagnostics on the BalPure® system, and is included in appendix A.5.
A second method is typically used for measuring lower range TRO (as Cl2) in potable water
and waste water streams. A Hach colourimeter can be used to measure the TRO (as Cl2) in
ballast tanks and in the deballast stream pre- and post-neutralization. The TRO (as Cl2)
oxidizes triiodide ion (I3-) to iodine (I2). The iodine and free chlorine react with DPD
(N,N-diethyl-p-phenylenediamine) to form a red solution. The colour intensity is proportional
to the TRO concentration. This method is also provided in appendix A.5.
During land-based testing at NIOZ, TRO (as Cl2) measurements were performed with a Hach
Pocket Colorimeter using Hach Method 8167 (equivalent to EPA Method 330.5). For TRO
(as Cl2) in the 0.1 mg/L to 8.0 mg/L range the method has a detection limit of 0.1 mg/L. For
TRO (as Cl2) in the 0.02 mg/L to 2 mg/L range the method has a detection limit of 0.02 mg/L.
Residual sodium bisulfite in post-neutralization discharge samples was measured using the
Hach SU-5 test kit with a titration/iodometric method. Information on the above methods is
provided in Table 18 and appendix A.5.
7.2
Analysis of Disinfection By-products (DBPs)
Treated ballast water samples were collected immediately after neutralization at discharge.
Samples for chemical analysis were stored in proper sample containers at 4°C and
transported to the designated laboratory within 24 hours of collection. Analysis of the
samples occurred within the time specified under standard laboratory procedures. Qualified
and accredited laboratories were utilized for analysis of treated water samples. Acceptable
field-testing analytical methods were also used where applicable (e.g., TRO (as Cl2) and
bisulfite). The methods used to determine DBP concentrations are listed in Table 18 below
and more details are provided in appendix A.5. Information regarding quality assurance from
the analytical laboratories is included in appendix A.6.
Table 18: Analytical Methods
Substance/Parameter
TRO (as Cl2)
High Range: 0.1-8.0 mg/L
Low range: 0.02-2.0 mg/L
Bisulfate measured as sulfate ion
Bisulfite measured as sulfite ion
THMs
HAAs
2,4,6-Tribromophenol
Monobromoacetonitrile
Bromate
Chlorate
1
Method
Hach Method 8167
(Equivalent to
US EPA Method 30.5)
NEN-EN-ISO 10304-1
Hach Test Kit SU-5
NEN-EN-ISO 15680
US EPA Method 552.2
US EPA Method 528
US EPA Method 524.1
US EPA Method 317
US EPA Method 300.1
= Method Detection Limit (MDL).
= Minimum Reporting Level (MRL).
3
= Limit of Detection (LOD).
2
I:\MEPC\61\2-9.doc
Description
Detection Limit
DPD, Colorimetric
High Range: 0.1 mg/L
1
Low Range: 0.02 mg/L
Ion chromatography
Titration/Iodometric
Gas chromatography
Gas chromatography
Gas chromatography
Gas chromatography
Ion chromatography
Ion chromatography
1.0 mg/L1
1 mg/L1
0.1 μg/L
1.0 -10 μg/L3
0.1-0.2 μg/L3
1-10 μg/L3
10 µg/L2
50 µg/L2
1
MEPC 61/2/9
Annex, page 28
8
USE OF ACTIVE SUBSTANCE
8.1
Manner of application
The BalPure® system can service ships with ballast water flow requirements
from 100 to 10,000 cubic metres per hour. The BalPure® system size (electrolytic cell size) is
defined by the ship's designed ballast water flow rate, but because the system has a 100%
turn down capability the hypochlorite production rate is matched to the actual measured
ballast flow rate. Treatment is done during ballasting operations allowing the biocide solution
to be generated anywhere on the ship and injected as needed. This would apply to ships
with one or multiple ballast systems or ships with multiple ballast pumps mounted within
separate ballast tanks. The system can be delivered as a complete system on one skid or
divided into seven separate smaller skids based on specific unit operation (pumping,
hypochlorite generation, hydrogen-hypochlorite separation, bisulfite storage, bisulfite
metered addition, instrument and controls, and power rectification). This allows multiple skid
locations as space is available throughout the vessel. The multiple skid design is perfect for
retrofit applications and the one skid system is best for new buildings.
Operational control of the BalPure® system is accomplished by the main control panel
attached to the hypochlorite generation unit or by a remote control panel that can be placed
where most appropriate for a specific vessel. Together, the control panel and the
transformer/rectifier unit comprise the main Programmable Logic Controller (PLC) control
and rectification components. The control panel provides a visual display of the status of the
rectifier DC voltage, current, and can alert the operator of any system alarms via the operator
interface terminal (OIT). The main control panel also has a local emergency stop push
button. All major equipment such as booster pumps, bisulfite metering pumps, and hydrogen
blowers can be controlled from the main control panel. All monitoring equipment such as
flow meters and ORP probes send the output in the form of 4-20 mA signals. All system
control screens are password protected to limit operator modification to existing control logic.
Only properly trained ship's crew members and BalPure® technicians will be allowed to
access password-protected portions of the PLC.
Other system monitoring and control devices include a magnetic flow transmitter to monitor
the flow of seawater at the electrolyzer inlet, transformer temperature switches that monitor
the internal temperature of the rectifier, and airflow switches that monitor the hydrogen gas
dilution blowers.
8.1.1
Process flow description
The BalPure® system is designed to operate automatically and has two operation processes:
ballasting and deballasting. During ballasting, the biocide solution is produced and injected
into the ballast water intake piping (maximum treatment dose of 15 mg/L TRO as Cl2); during
deballasting sodium bisulfite is added directly to the ballast water discharge piping. The
ballasting process is discussed first, followed by the deballasting process. A complete
process flow diagram (PFD) of the system is included in appendix A.3. Figures 1 and 2
presented below provide a simplified overview of each phase of the treatment process.
8.1.1.1 Ballasting process – ballast water intake
Very generally, during the automatic ballasting process the system will sense that adequate
seawater flow is available using a flow meter in the main ballast line. Once the system is
primed with sufficient water (an approximate 1-minute cycle), the transformer/rectifier will
supply DC current to the electrolyzer and initiate the electro-chemical generation process.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 29
The hypochlorite production rate is primarily tied to the ballast flow rate and achieves the
pre-set required oxidant concentration by modulating the rectifier output amperage to coincide
with the ballast flow rate. This is considered the large or gross adjustment. The produced
oxidants are then injected into the main ballast line. If necessary, the system may also be
operated manually. Figure 1 below provides an overview of the BalPure® ballasting process.
Figure 1: Overview of the BalPure® Ballasting Process
The BalPure® system remains in a stand-by mode until the flow meter in the main ballast line
detects ballast water flow and activates the BalPure® system. In the ballasting process,
seawater from the sea chest will be filtered with a 40 micron stainless steel mesh filtration unit.
Filtration is only required during ballast uptake. If an installation requires that seawater be
taken from a source other than filtered ballast water (e.g., seawater cooling) a duplex strainer
filters the seawater to remove any particles larger than 800 microns. Using an inline booster
pump, the BalPure® system typically receives <1% of the total incoming ballast water flow as a
side- stream off the main ballast intake line. The booster pump increases the line pressure to
provide proper flow through the hypochlorite generation unit and allow solution injection into
the main ballast line. An inlet flow transmitter, designed to protect the treatment system, will
automatically shut down the electrical current to the electrolyzer should seawater flow through
the electrolyzer drop below 80% of the design flow rate. The filtered seawater passes through
a heat sink where it absorbs excess heat generated by the silicon-controlled rectifiers. The
seawater then passes through a series of electrolytic cells which are connected to the
transformer/rectifier. The electrolyzer units then generate the Active Substance along with
hydrogen gas as a by-product.
Immediately after exit from the electrolytic cells, the combined seawater/biocide solution
(liquid) and hydrogen (gas) is delivered to a patented cyclone separation device where the
hydrogen is separated from the biocide/seawater solution. Hydrogen gas does not enter the
ballast water piping or tanks. The hydrogen gas is directed to a vent stack where it is diluted
by forced air blowers and vented to the atmosphere outside of the ship. To ensure proper
ventilation the vent line is serviced by two redundant blowers coupled to sail switches.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 30
The sail switches ensure proper air flow to dilute the air stream to <1% hydrogen. The LEL
for hydrogen is 4% and the operating limitations on the system provide a four-fold safety
factor. The PLC monitors proper air flow and will shut down the system, resulting in an alarm
condition if proper ventilation air flow is not maintained. Both blower motors and sail
switches are tied to an automatic emergency shutdown for the production unit in the unlikely
event all four devices fail. For additional safety, a hydrogen sensor with alarm will be
provided in the immediate proximity of the hypochlorite generation unit.
For optimum hypochlorite generator performance (i.e. to produce 90% of theoretical values), the
inlet seawater temperature should be at least 15°C and have a sodium chloride concentration
of at least 19,000 mg/L (19 PSU). However, the BalPure® system can operate at temperatures
as low as 5°C and salinities of 10,000 mg/L (10 PSU). Less optimal conditions result in a
slightly decreased hypochlorite production rate to 20% less than optimum. The hypochlorite
production rate of the electrolytic cells is directly related to chloride ion availability and mobility.
The salinity (PSU) of the source water determines the chloride ion availability, while temperature
affects chloride ion mobility. These parameters impact the operating voltage of the electrolytic
cells. For instance, when chloride ions are abundantly available and mobile, the operating
voltage and hypochlorite production within the electrolytic cells will be optimum. If chloride ions
and/or temperature are low, the operating voltage increases proportionally and hypochlorite
production will be reduced. The BalPure® system is designed to adjust the hypochlorite
production rate by monitoring the operating voltage of the electrolytic cells and increasing the
rectifier operating amperage to sustain the TRO (as Cl2) concentration required to treat incoming
ballast water (maximum treatment dose of 15 mg/L TRO (as Cl2)). These adjustments are
small and used to control the hypochlorite production rate to a narrow range (fine tuning).
The BalPure® system can also operate at higher salinities, such as ≥30,000 mg/L (≥30 PSU).
In this case where chloride ions are highly abundant, the generator will only produce the
design hypochlorite concentration. This is because higher salinity does not increase the
efficiency or the production rate of the electrolytic cell beyond the optimum.
As mentioned above, the BalPure® unit is designed to operate in seawater with salinities
≥10 PSU. However, with minor process adjustments, the BalPure® unit can operate in
fresh water. For operation in fresh water, an alternative supply of saltwater input to the
BalPure® unit is required. Because the BalPure® unit requires only a small amount (<1% of
total incoming ballast flow), existing onboard alternative sources of seawater can be used.
By monitoring the operating voltage of the electrolytic cells and adjusting the amperage
applied, the PLC programming of the BalPure® system guarantees effective operation over a
wide temperature and/or PSU range.
8.1.1.2 Deballasting and neutralization process – ballast water discharge
In the deballasting process, the final phase of treatment, residual chlorine present in the
ballast tank is neutralized (de-chlorinated) with sodium bisulfite just prior to discharge from
the ship. The holding time that treated ballast water needs to be retained before discharge is
discussed further in section 11.5. Neutralization is accomplished using ORP technology and
bisulfite metering pumps. Two ORP probes are used; one confirms the presence of residual
oxidant exiting the ballast tanks, while the second probe monitors and controls the addition of
sodium bisulfite to neutralize TRO (as Cl2) during ballast water discharge. The first ORP
probe is located upstream of the bisulfite injection point, and the second ORP probe is
located downstream of the bisulfite injection point.
During deballasting, the main ballast line filter used during the ballast uptake process is not
required and is by-passed automatically.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 31
Figure 2: Overview of the BalPure® Deballasting Process
ORP technology is based on the potential measurement between two dissimilar metals within
the ORP probe. ORP is not a quantitative measure of oxidant or bisulfite concentration but
rather a qualitative measure that confirms the presence of oxidizing or reducing agents in the
water. ORP technology allows for an in-line rapid determination of the amount of oxidation
(or reduction) potential of the water. ORP is measured in millivolts (mV) and increases or
decreases in direct relation with the oxidant residual in the water (Kelley, 2004). For example,
natural waters have an ORP reading in the range of 100-150 mV. When hypochlorite is added
to water, the ORP reading increases with an increase in hypochlorite dosage. Similarly, when
a de-chlorinating agent such as sodium bisulfite is added to the water, the ORP reading will
drop to a low mV level (Kelley, 2004). In this way, ORP measurements provide a practical and
efficient method of optimizing water disinfection and controlling neutralizing agent dosage.
The BalPure® BWMS uses ORP readings as a general indicator of the presence/absence of
residual oxidants, but STDN believes that ORP measurements are not sufficient to accurately
quantify TRO levels.
The first BalPure® ORP probe confirms that there are residual oxidants in the treated water
being discharged from the ballast tank. In principle, this confirmation of oxidants translates
to affirmation that there are no living organisms in the discharge. The ORP reading at the
first probe is typically between 700 and 800 mV and is used as an indicator that residual
oxidant is present. The second ORP probe measures the ORP value of the deballast stream
after bisulfite has been added to the discharge piping. This ORP value is typically <200 mV
(similar to natural water) and is used to control the addition of bisulfite solution to ensure
complete neutralization of residual oxidants. The low ORP value is an indicator that the
residual oxidant has been neutralized.
It is important to note the data from land-based testing confirms that the TRO (as Cl2)
concentration is below detection levels post neutralization with sodium bisulfite. This verifies
that residual oxidant neutralization with sodium bisulfite at discharge was effective at all
ballast discharges and ensures that the maximum allowable discharge concentration
(MADC) of <0.20 mg/L TRO (as Cl2), as recommended by the GESAMP-BWWG, is not
exceeded (see section 11.1).
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 32
With the mixing effect of the deballast water pump and the discharge pipe, the bisulfite will
easily react with any free oxidants that may be present. As a fail-safe measure, the BalPure®
system is fitted with two redundant bisulfite metering pumps; one pump is the primary dosing
pump and the second is an on-line ready spare.
In the unlikely event of an equipment failure, the neutralization process can also be operated
manually to ensure that residual oxidants are neutralized during discharge. This is
accomplished by the operator manually setting the bisulfite metering pump rate in the PLC.
The delivery rate of bisulfite can be set based on the stoichiometric ratio of oxidant to
neutralizing agent at 1:2 parts. Thus the sulfite metering pumps are set based on the
maximum discharge ballast water flow rate and hypochlorite concentration.
8.1.2
Chemical storage and handling
The only chemical that will require onboard storage and handling is the neutralizing agent,
sodium bisulfite. The only potential activities that may require "handling" of bisulfite is either
system maintenance or chemical re-supply operations. During the previous evaluation
undertaken for STDN's application dossier for Basic Approval (MEPC 60/2/9, section 8.1.3)
the Group recognized all risk evaluations of the ship and personnel including consideration of
the storage, handling, and application of sodium bisulfite as sufficient and considered that
this BWMS will not pose unacceptable risk regarding the exposure to bisulfite and treated
ballast water (MEPC 60/2/16, sections 7.1 and 7.2). No changes have been made in the
full-scale operation of the BalPure® system since the submittal of STDN's application dossier
for Basic Approval. Therefore the previous evaluations made by the Group remain valid.
8.1.3
Various procedures and management measures
Technicians and ship's crew will be sufficiently trained in procedures and management
measures concerning fire, accidental release, marine environmental release, and controlled
release according to methods outlined in STDN's application dossier for Basic Approval
(MEPC 60/2/9, section 8.1.3). During the previous evaluation undertaken for STDN's
application dossier for Basic Approval, the Group recognized all working principles of the
BalPure® system as sufficient and considered that this BWMS will not pose unacceptable risk
to the health of the crew and the general public (MEPC 60/2/16, sections 7.1 and 7.2). No
changes have been made in the full-scale operation of the BalPure® system since the
submission of STDN's application dossier for Basic Approval. Therefore the previous
evaluations made by the Group remain valid, and no change to procedures and management
measures are presented in this dossier.
9
MATERIAL SAFETY DATA SHEETS (G9: 4.2.7)
Information on the hazard classifications of Active Substances and Relevant Chemicals was
presented in sections 9.1, 9.2 and 9.3 of STDN's application dossier for Basic Approval
(MEPC 60/2/9) and all Material Data Safety Sheet (MSDS) were provided. In this Final
Approval dossier, all MSDSs, including the three additional DBPs (dibromochloroacetic acid,
tribromoacetic acid, and 2,4,6-tribromophenol) that were measured in treated ballast water
during land-based testing are provided in appendix A.4.
It is important to note that these DBPs may be formed in situ at low concentrations as a result
of ballast water treatment. Concentrated solutions of these DBPs will never be transported
or utilized on board ship. As such, typical MSDSs for these low level (µg/L range) substances
do not accurately represent the potential hazards in treated ballast water. Determining the
hazards for these substances at µg/L levels is not feasible when the MSDSs reflect hazards
for much higher concentrations.
I:\MEPC\61\2-9.doc
MEPC 61/2/9
Annex, page 33
10
RISK CHARACTERIZATION AND ANALYSIS
10.1
Screening for persistence, bioaccumulation, and toxicity (G9: 5.1)
Table 19: PBT Criteria Evaluation
Substance
Persistence (P) Half-life:
>60 Days in Marine Water (MW), or
>40 Days in Fresh Water (FW), or
>180 Days in Marine Sediment (MS), or
>120 Days in Fresh Water Sediment (FWS)
(YES or NO)
Bioaccumulation
(B) BCF>2,000
Log Kow ≥ 3
Toxicity (T)
Chronic
NOEC < 0.01 mg/L
(YES or NO)
(YES or NO)
No
Log Kow = -0.87
No
Lowest NOEC =
0.048 mg/L
(Crustacean)
No
BCF = 3.2
Log Kow =-0.78
Koc = 13.2
No
Lowest EC50 =
1.0 mg/L (Algae)
Active Substances
Hypochlorous acid
Hypobromous acid
No
<2 hours (EU RAR Sodium hypochlorite, 2007)
FW
No
<2 hours (No specific data located, based on
hypochlorous acid)
FW
Relevant Chemicals
Bromate
No
15 days (EPI Suite, 2009)
Water type not specified; Temperature = 25°C;
2,4,6-Tribromophenol
No
1.21 days (CICADS 66, 2005)
FW
No
BCF = 3.2
Log Kow = -4.6
Koc = 31.8
No
BCF = 83 - 513
Log Kow =3.89
Koc = 1,186
No
Lowest EC50 =
13.6 mg/L (Algae)
No
Lowest NOEC =
0.10 mg/L
(Crustacean)
THMs
Chloroform
No
0.25 days (Yang, 2001); Not expected to
adsorb into sediment (HSDB/TOXNET 2009)
MW
Bromoform
No
0.3 days (EU RAR Sodium hypochlorite, 2007)
FW
Dichlorobromomethane
No
0.08 days (EU RAR Sodium hypochlorite, 2007)
FW
Dibromochloromethane
No
0.11 days (EU RAR Sodium hypochlorite, 2007)
FW
No
BCF = 2.9-10.35
Koc = 153-196
No
BCF = 14
Log Kow 2.4
Koc = 35
No
BCF = 7
Log Kow = 2
Koc = 35-251
No
BCF = 9
Koc = 84
No
Lowest NOEC =
1.5 mg/L (Fish)
No
Lowest NOEC =
8.5 mg/L (Fish)
No
Lowest LC50 =
67.4 mg/L (Fish)
No
Lowest LC50 =
34mg/L (Fish)
HAAs
Bromochloroacetic acid
Monochloroacetic acid
Monobromoacetic acid
I:\MEPC\61\2-9.doc
No
2.7 days (Hashimoto et al., 1998); Not expected
to adsorb to suspended solids or sediment.
(HSDB/TOXNET 2009)
FW; Temperature = 20°C
No
3.58 Days (Hanson et al., 2002)
FW; Temperature = 18.7-23.8°C; pH = 7.7-8;
DO= 92-11.3 mg/L; Alkalinity = 158-171 mg/L
No
3.2 days (Hashimoto et al., 1998); Not expected
to adsorb to sediment. (HSDB/TOXNET 2009)
FW; Temperature 20°C
No
BCF = 3.2
Log Kow = 0.61
Koc = 1.9
No
BCF = 3.2
Log Kow = 0.22
Koc = 31
No
BCF = 3.2
Log Kow = 0.41
Koc = 39.8
Data not located.
No
Lowest NOEC =
32 mg/L
(Crustacean)
No
Lowest NOEC =
1.4 mg/L (Algae)
MEPC 61/2/9
Annex, page 34
Persistence (P) Half-life:
>60 Days in Marine Water (MW), or
>40 Days in Fresh Water (FW), or
>180 Days in Marine Sediment (MS), or
>120 Days in Fresh Water Sediment (FWS)
(YES or NO)
Substance
Dichloroacetic acid
No
5.4 days (Hashimoto et al., 1998)
FW; Temperature 20°C
Dibromochloroacetic acid
No
3.67 days (Hashimoto et al., 1998)
FW; Temperature 20°C
Dibromoacetic acid
No
3.2 days (Hashimoto et al., 1998)
FW; Temperature 20°C
Tribromoacetic acid
No
4.2 days (Hashimoto et al., 1998)
FW; Temperature 20°C
Trichloroacetic acid
No
14.37 days (Ellis et al., 2001)
FW; Temperature 20°C
Sodium bisulfite
Other Chemicals
No
0.000747 days (Yan et al., 2007)
Salinity not specified; Temperature = 25°C;
pH = 4; DO = 7.86 mg/L
Bioaccumulation
(B) BCF>2,000
Log Kow ≥ 3
Toxicity (T)
Chronic
NOEC < 0.01 mg/L
(YES or NO)
(YES or NO)
No
BCF = 0.3
Log Kow = 0.92
Koc = 75
No
BCF = 3.16
Log Kow = 1.62
Loc = 3.23
No
BCF = 0.17
Koc = 1.5
No
BCF = 0.63
Koc = 5.3
No
Lowest EC50 =
23
mg/L (Crustacean)
Data not located.
No
Lowest LC50 =
69 mg/L (Fish)
Data not located.
No
BCF = 0.1-1.7
Log Kow = 1.33
Koc = 130
No
Lowest NOEC =
100 mg/L (Algae)
No
BCF = 3.2
Log Kow = -6.85
Koc = 2.21
No
Lowest LC50 =
81 mg/L
(Crustacean)
Based on an evaluation of the available data presented in the Table, none of the substances
meet all three criteria to be considered as PBT substances.
10.1.1
Persistence (G9: 5.1.1.1)
Using the half-life criteria specified in Procedure (G9) (resolution MEPC.169(57)) of more
than 40 days in fresh water, 60 days in marine water, marine sediment persistence more
than 180 days, or fresh water sediment persistence greater than 120 days, an evaluation of
the environmental persistence data for Active Substances, Relevant Chemicals, and other
chemicals indicates that none of the substances are likely to be persistent in the
environment.
10.1.2
Bioaccumulation (G9: 5.1.1.2)
Using the criteria specified in Procedure (G9) (resolution MEPC.169(57)) of either BCF >2000
or Log Kow ≥3, an evaluation of the available data for Active Substances, Relevant Chemicals,
and other chemicals indicates that the substances have low potential for bioaccumulation.
Although 2,4,6-tribromophenol has a reported Log Kow of 3.89 (OECD, 2003) which is
slightly above 3, the BCF is well below the criteria of 2000.
10.1.3
Toxicity tests (G9: 5.1.2.3)
Due to the limited availability of chronic aquatic toxicity data for some substances, the
evaluation for toxicity was based on all available data. In some cases, acute endpoint data
was utilized when available. For substances where no toxicity data points could be located,
the data with respect to the other two PBT criteria is available and therefore, a PBT
determination can still be made.
I:\MEPC\61\2-9.doc
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Annex, page 35
With the exception of substances having limited toxicity data, all other substances did not
have chronic NOEC or E(L)C50 values <0.01 mg/L. Therefore, the criterion to be considered
a toxic substance is not met.
11
EVALUATION OF THE TREATED BALLAST WATER (G9: 5.2)
Numerous studies have been conducted on the BalPure® system to evaluate various aspects
of treated/neutralized water. In addition to the aquatic ecotoxicity data presented in section 3,
data on TRO (as Cl2), water quality parameters (e.g., salinity, pH, particulate organic carbon
(POC), dissolved organic carbon (DOC), total suspended solids (TSS)), and disinfection
by-products (DBPs) have been measured and recorded. Treated ballast water samples were
collected immediately after neutralization at discharge. Samples were stored in proper sample
containers at 4°C and transported to the designated lab within 24 hours of collection. Analysis
of the samples occurred within the time specified under standard laboratory procedures.
11.1
Total Residual Oxidants
During testing of the BalPure® system conducted at the NIOZ land-based testing facility in 2009,
hypochlorite treatment was applied and TRO (as Cl2) was measured at different time
intervals after treatment. TRO (as Cl2) was evaluated immediately after treatment (T0), 1 day
after treatment (T1), 5 days after treatment (T5), and after neutralization on day 5 (post
neutralization). The average TRO (as Cl2) at each time interval for 6 low salinity test cycles
and 6 high salinity test cycles are shown below in Table 20.
Table 20: Average Oxidant Values (mg/L) in Treated Ballast Water
®
Test Cycle
Salinity
Low Salinity
(23.68 PSU)
High Salinity
(33.90 PSU)
BalPure
Treatment Dose
(Set Point)
TRO (as Cl2)
@ T0
TRO (as Cl2)
@ T1
TRO (as Cl2)
@ T5
TRO (as Cl2) Post
Neutralization
14.83
14.80
7.19
4.46
Not Detected
13.17
12.36
4.97
2.98
Not Detected
Not Detected = <0.02 mg/L (Hach Method 8167)
The data indicate that the applied hypochlorite treatment dose is confirmed following treatment
by the TRO (as Cl2) measurement at T0. As expected, the TRO (as Cl2) concentration
decayed quickly (TRO (as Cl2) at T1) following treatment, and then more slowly after the
demand of the water was met (TRO (as Cl2) at T5). Lastly, the data confirm that the TRO
(as Cl2) concentration is below detection levels post neutralization with sodium bisulfite. This
verifies that residual oxidant neutralization with sodium bisulfite at discharge was effective at all
ballast discharges and ensures that the maximum allowable discharge concentration (MADC)
of <0.20 mg/L TRO (as Cl2), as recommended by the GESAMP-BWWG, is not exceeded.
Also, the features of the BalPure® system pertaining to neutralization and ORP control
(section 8.1.1.2) ensure sodium bisulfite addition for effective neutralization.
11.2
Water quality parameters
Water quality data was collected by the researchers at NIOZ during testing of the BalPure®
system in 2009. Land-based tests were done using natural waters taken from the Wadden
Sea, with minimal amendments to alter water quality. Variation in water quality is caused by
tidal and wind influences, which results in variable concentrations of TSS and POC. The
average values for brackish water samples (low salinity) and marine water samples (high
salinity) are presented in Table 21 below. Data is as provided to STDN by NIOZ.
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Table 21: Water Quality Data
Parameter
Control
Treatment
Brackish Water (low salinity)
T0
T5
T0
T5
pH
8.33
8.25
8.52
7.90
Temperature (˚C)
11.45
11.35
11.05
11.23
Salinity (PSU)
24.05
24.05
23.68
23.68
POC (mg/L)
16.34
25.79
15.31
5.62
DOC (mg/L)
2.85
2.69
3.00
3.50
TOC (mg/L)*
19.19
28.48
18.31
9.12
TSS (mg/L)
46.83
16.20
41.91
12.58
DO (%)
111.05
91.87
138.08
119.60
Marine Water (high salinity)
T0
T5
T0
T5
pH
8.10
7.92
8.33
7.50
Temperature (˚C)
14.56
14.30
14.66
14.48
Salinity (PSU)
33.40
33.40
33.90
33.90
POC (mg/L)
7.63
4.96
8.07
3.68
DOC (mg/L)
3.04
2.77
3.31
3.69
TOC (mg/L)*
10.67
7.73
11.38
7.37
TSS (mg/L)
18.55
10.66
19.60
8.38
DO (%)
92.25
68.11
126.94
106.02
*
TOC = DOC +POC
The physical and chemical properties of treated ballast water were provided in STDN's
application dossier for Basic Approval (section 6 and Table 21).
11.3
Chemical analysis of disinfection by-products in treated ballast water
During land-based testing of the full commercial BalPure® system conducted at NIOZ
in 2009, treated ballast water discharge was evaluated for disinfection by-products (DBPs).
DBP concentrations from three low salinity and three high salinity test cycles were quantified.
During each test cycle, samples were collected on Day 1 (24 hours post-treatment) and Day 5
(5 days post-treatment), resulting in 6 separate analyses for each water type. All samples
were neutralized at discharge to ensure that the data represent full-scale employment
(hypochlorite treatment + sodium bisulfite neutralization) of the ballast water system.
Table 22 presents DBP data for samples collected on Day 1 (24 hours post-treatment) for
low salinity (23.68 PSU) and high salinity (33.90 PSU) test cycles. Table 23 presents
DBP data for samples collected on Day 5 (5 days post-treatment) for low salinity (23.68 PSU)
and high-salinity (33.90 PSU) test cycles.
Table 22: Post-Treatment Disinfection By-product Concentrations – Day 1
(Table 22 provided in confidential dossier.)
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Table 23: Post-Treatment Disinfection By-product Concentrations – Day 5
(Table 23 provided in confidential dossier.)
For THM analysis, three of the four substances tested in both high and low salinity cycles
indicate that bromoform, DBCM and DCBM had measurable concentrations in treated/
neutralized discharge. Chloroform was not detected in any sample analysed. Low levels
(0.15-2.7 µg/L) of bromoform were also present in untreated (control) water for both high and
low salinity test cycles. As previously mentioned in section 2.3.1, bromoform is a chemical
naturally produced by many algal species such as Macrocystis pyrifera and Corallina pilulifera
(HSDB/TOXNET Tribromomethane, 2009; Goodwin et al., 1997; Ohsawa et al., 2001).
For HAA analysis, MBAA, DBAA, TBAA, MCAA, DBCAA and BCAA had measurable
concentrations in low salinity test cycles. In high salinity test cycles, MBAA, DBAA, TBAA,
DCAA, DBCAA and BCAA were present with measurable concentrations.
In brackish water test cycles, 2,4,6-TBP had measurable concentrations in treated water
(0.67-1.3 µg/L), as well as in untreated (control) water (0.44-1.80 µg/L). The background
concentration was consistently significant (see discussion on modelling 2,4,6 TBP;
section 11.8.2). The substance, 2,4,6-TBP, has been documented to occur in natural
environments, either as a pollutant from anthropogenic sources (wood industry, antifungal use)
or from natural production by marine benthic organisms (OECD SIDS, 2003). Therefore, the
presence of 2,4,6-TBP in control samples is consistent with the findings of other studies.
Sodium bisulfite is added in excess to ensure complete neutralization of remaining oxidants
in ballast water discharge. In one sample, a maximum concentration of 8 mg/L sulfite ion
was measured in ballast water discharge. The median concentration measured for all
samples was 5 mg/L. Bisulfite was measured immediately after injection into the discharge
pipe to ensure that an excess is present, which the data confirms. The bisulfite
concentration ranges in low and high salinity test cycles was 2.0-8.0 mg/L and 2.0-3.0 mg/L,
respectively. As discussed above in section 2.4.1, bisulfite is converted to bisulfate, and
ultimately to sulfate ion during chemical reduction. Both the control and treated waters were
analysed to verify that the excess of bisulfite does not significantly increase the sulfate ion.
The data in Tables 22 and 23 show the difference between the measured sulfate ion in
control and treated samples is insignificant (<10%). Considering the typical concentration of
sulfate ion in natural waters, the increase of sulfate ion in ballast water discharge is not
considered environmentally relevant. GESAMP-BWWG agrees that sulfate ion is ubiquitous
in the marine environment and considered that the discharge or environmental
concentrations of sodium bisulfite should not pose unacceptable environmental risks
(MEPC 60/2/16, section 3.1.1.4).
As discussed in section 5.4, formation of DBPs is dependent upon several variables such as
Active Substance dose, contact time, pH, and organic matter content. Data from the
BalPure® discharge reflects those trends. For instance, the highest THM and HAA formation
occurred in the brackish water treatment where the hypochlorite dose, organic matter, and
suspended solids were the highest. Similarly, the lowest THM and HAA formation occurred
in the seawater study where the hypochlorite dose, organic matter and suspended solids
were at lower levels.
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11.4
Ecotoxicity testing of treated ballast water, land-based testing
Samples of water treated with the BalPure® system during land-based testing at NIOZ
were evaluated by Grontmij|AquaSense (The Netherlands) and Chemex Environmental
International Ltd. (UK). Ecotoxicity data is presented in section 3 and Tables 3 and 5.
Toxicity tests were conducted with six taxonomic groups including bacteria, algae,
crustaceans, rotifers, mollusks and fish in two water types; low salinity (23.68 PSU) and high
salinity (33.90 PSU). The samples for ecotoxicity testing were collected on Day 1 and on
Day 5 after ballast water treatment/neutralization. All tests were performed according to
laboratory protocols based on internationally recognized ISO, OECD, ASTM, and
Parcom/OSPAR guidelines. Documentation of quality assurance for Grontmij|AquaSense
and Chemex Environmental International Ltd. are included in appendix A.6.
The acute testing data indicate that 100% whole effluent did not have toxic effects on five of
the six species tested (Table 3). One of four acute tests with the crustacean, Acartia tonsa,
in the low salinity sample collected 24 hours after treatment (Day 1) indicated there was a
moderate effect in the two highest test concentrations (100% and 32% sample). This is
reflected by a NOEC of 18% volume (Grontmij|AquaSense, 2009).
It is important to note that during tests with Acartia moderate effects were also
observed in a control (untreated NIOZ harbour water) sample (EC20 of 58% sample)
(Grontmij|AquaSense, 2009). A possible explanation for the moderate toxic effect in the
treated and control samples is the presence of Phaeocystis, an algal species known to be
abundant in the NIOZ harbour and to excrete allelochemicals. Although not a highly toxic
algal species, the massive blooms often result in ecosystem effects. Residual grazing
deterrents and growth retarding compounds were likely to be the main cause of the effects on
Acartia tonsa in the control and treated ballast water test cycles (Veldhuis and Kools, 2009).
Phaeocystis was present in the NIOZ harbour during the whole season of testing but was
particularly abundant during the first low salinity test cycles (Veldhuis and Kools, 2009),
which corresponds with when effects were observed in the Acartia tests.
All other acute (Table 3) and chronic (Table 5) tests with Acartia, as well as the five other
species tested, demonstrate that 100% whole effluent sample had no toxic effect, indicating
that the NOEC of 18% (Table 3) is an outlying data point.
11.5
Determination of holding time
Because the BalPure® system employs an oxidant neutralization step at discharge, there is
no specified holding time required before treated water can be safely discharged to the
environment. Using ORP technology (discussed in section 8.1.1.2) sodium bisulfite can be
added to the ballast water discharge line at the concentration needed to ensure that all
residual oxidants are neutralized, regardless of when deballasting needs to occur. The
neutralization reaction between sodium bisulfite and TRO (as Cl2) is extremely quick and
occurs well before water is discharged from the ballast tank.
Therefore, the holding time that treated ballast water needs to be retained is determined by the
amount of contact time required to properly disinfect and inactivate AIS. Studies performed at
the University of Washington determined that at low (<2 mg/L) TOC concentrations 98-100%
of organisms were inactivated 5 hours after hypochlorite treatments of 2.95-3.71 mg/L
(Herwig et al., 2006). Studies performed at the Naval Research Laboratory determined BalPure®
hypochlorite treatments of 14-16 mg/L effectively inactivated >99% of organisms 24 hours
after treatment in seawater with 10 mg/L TOC (NRL, 2007). These studies indicate that even
if a ship had to discharge treated ballast water shortly after hypochlorite treatment, the number
of live organisms would be very limited and no aquatic toxicity could be expected from
neutralized discharge.
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11.6
Reaction with organic matter
As discussed in STDN's application dossier for Basic Approval (MEPC 60/2/9) and in
section 5.4, chlorine-based water disinfection can result in the formation of THMs, HAAs or
other DBPs. The concentration of these DBPs resulting from disinfection is based on the
Active Substance dose as well as the parameters of the water being treated (e.g., organic
matter, pH, temperature), with the amount of organic matter being of significant influence.
Lower organic matter levels will reduce the amount of DBPs formed. The BalPure® system
filters incoming ballast water, which will reduce the amount of organic matter in treated water,
and thereby, the DBPs formed during disinfection. The levels of DBPs in treated/neutralized
ballast water are presented in section 11.3, Tables 22 and 23.
Because TRO (as Cl2) is neutralized during discharge, and also considering that DBPs are
present in the µg/L range in ballast water discharge, no additional reactions with organic
matter are expected to occur once ballast water is released into the environment.
11.7
Characterization of degradation route and rate (G9: 5.3.5)
Table 16 above includes degradation data for substances not previously analysed for or
presented in STDN's application dossier for Basic Approval (MEPC 60/2/9) and which were
measured in treated/neutralized ballast water during land-based testing. Degradation
information on all previously measured substances was presented in the Basic Approval
dossier (MEPC 60/2/9, Table 16).
The data indicate that both biotic and abiotic modes of degradation are possible for 2,4,6-TBP,
and degradation in anaerobic sediments is rapid (half-life of ~4 days (CICADS 66, (2005)).
In an activated sludge study, 2,4,6-TBP reached 49% of the biological oxygen demand (BOD)
in 28 days (CICADS 66, 2005). However, in 3-day biodegradation tests in river water, 2,4,6-TBP
(10 mg/L) was degraded by 82% (CICADS 66, 2005). Based on the low concentrations
(maximum = 1.3 µg/L) of 2,4,6-TBP present in ballast water discharge and the rapid
degradation of 2,4,6-TBP documented in water and sediment, there is low potential for
persistence and impacts to the aquatic environment from 2,4,6-TBP.
Degradation data for DBCAA and TBAA is limited. However, the stability of HAAs in water
was evaluated in Tokyo Bay (Hashimoto, et al, 1998). In river water, DBCAA (20 µg/L)
degraded to <0.069 µg/L after a 30-day incubation. Similarly, TBAA (10 µg/L) degraded
to <0.070 µg/L after a 30-day incubation. The studies also showed that abiotic and biotic
degradation occurred for HAAs. This was demonstrated by samples that were allowed to
degrade with and without microbial inhibitors. Prior work with HAA stability also indicates
that bacterial enzymes (haloacid dehalogenases) decompose HAAs (Hashimoto et al., 1998).
As such, these substances are not expected to persist in the environment.
11.8
Prediction of discharge and environmental concentrations (G9: 5.3.8)
To determine the predicted environmental concentrations (PECs) of substances associated
with STDN BalPure® system, the MAMPEC modelling program was utilized. Deltares,
located in the Netherlands, developed the MAMPEC model and was commissioned by STDN
to derive PEC values. Appropriate emission scenarios were developed in consultation with
Deltares' hydrodynamic modelling experts. Due to Deltares' continued research and
development of the MAMPEC model, it was determined that a research version of MAMPEC
was the best to utilize for this assessment. This research version, not currently available on
the internet, incorporates the latest developments and is based on the last officially released
MAMPEC version (2.5.04) (Deltares, 2010).
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11.8.1
Hydrodynamic modelling approach
It is important to note that the MAMPEC model was designed as a rapid assessment tool to
evaluate the continuous leaching of anti-fouling products from ships' hulls. To determine
PEC values, MAMPEC employs a "steady state" approach, which implies that an equilibrium
concentration of a substance in a harbour is calculated under constant environmental
conditions as a result of continuous and constant emission (Deltares, 2010). This is very
different from the intermittent and non-continuous nature of ballast water discharges. Therefore,
the steady state approach in MAMPEC simulations likely overestimates PEC values and
provides a highly conservative, worst-case scenario.
In an effort to predict conservative environmental concentrations of substances present in
BalPure® treated/neutralized ballast water discharge, two different environmental
schematizations were employed. These two scenarios are labelled "Environment A" and
"Environment B".
Environment A applied a simulation environment defined by the "OECD-EU commercial
harbour" configuration which is the recommended scenario for risk assessment of antifoulants
in all OECD regulatory frameworks. The "OECD-EU commercial harbour" is a downsized
version of the whole Port of Rotterdam being four times smaller than the Rotterdam harbour,
with a surface area of 5 km2 (Deltares, 2010). To determine the amount of ballast water
discharge in the harbour, the ballast water discharge estimated by Van Niekerk (2008) was
used. According to the Van Niekerk study, a monthly estimate of ballast water discharge
amounted to 2.76 million m3 for the entire Port of Rotterdam. The flow rate specified in the
MAMPEC model was derived using the 2.76 million m3 ballast water discharge volume, which
equalled 1.10 m3/s. Given that the "OECD-EU commercial harbour" configuration is four
times smaller than the whole Port of Rotterdam, using this ballast water discharge flow rate
representative of the entire Rotterdam harbour constitutes a highly conservative worst case
scenario. Environment A also used the standard exchange flow of 5.1x107 m3 per tidal cycle,
which equals 68% of the total harbour water volume.
Environment B modelled substances present in BalPure® treated/neutralized ballast water
discharge using the same "OECD-EU commercial harbour" configuration and ballast
discharge flow rate as Environment A, with the exception that a lower tidal exchange flow
rate was used. This alternative environment had smaller density driven water exchange in
the harbour. The harbour water exchange resulting from density differences was assigned a
value of 0.02 kg/m3 in Environment B compared to the value of 0.4 kg/m3 assigned in
Environment A. The exchange flow rate for Environment B was 2.1x107 m3 per tidal cycle,
which equals only 28% of the total harbour water volume. Therefore, the Environment B
emission scenario and the resulting PEC values can be considered extremely conservative.
The harbour is smaller, the amount of water exchange (flushing) is greatly reduced, yet the
ballast water discharge rate is based on statistics for the whole Port of Rotterdam.
11.8.2
Determination of substance concentrations and decay rates for modelling input
Due to the oxidant neutralization step during ballast water discharge, the TRO (as Cl2) in
treated water discharge will not be present in measurable concentrations. Therefore, the
discharge and predicted environmental concentration (PEC) for TRO (as Cl2) is 0 mg/L.
The relevant substance concentrations used for MAMPEC modelling were based on analysis
of treated/neutralized ballast water samples drawn from the full-scale land-based test set-up
of the BalPure® system. For the purposes of modelling, the highest median concentration for
each Relevant Chemical with a measurable concentration (as presented in the Table 24),
regardless of the water type (high or low salinity water), was entered into the model.
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This approach ensured a representative evaluation of potential environmental risk as a result
of DBPs in ballast water discharge.
For each substance analysed, the median concentration was calculated by using all available
data to derive the most representative concentration for each salinity. For example,
six separate analyses for bromoform were performed in the low salinity test cycles, and the
median result of these 6 data points was derived. Because the data were not normally
distributed and the data set was relatively small (n<10) for each substance, median values
are the most representative and appropriate. Additionally, due to the layers of conservatism
already built into the environmental risk assessment (discussed in section 12.3) the use of
median values allowed for a more realistic assessment of discharge DBP concentrations.
The median result, as well as the minimum and maximum concentration, for each
Relevant Chemical is presented in Table 24 below.
In the case of TBAA, MCAA (low salinity cycles) and DCAA (high salinity cycles) the average
concentrations, rather than medians, were calculated and used for MAMPEC modelling.
This was done because a median calculation would not have been representative of all data
points. For these substances, the average is a more representative result. The results are
presented in Table 24 below.
Residual sodium bisulfite present in neutralized discharge was also measured; the data is
presented in Table 24 below.
Table 24: Median Disinfection By-product Concentrations
(Table 24 provided in confidential dossier.)
As discussed in sections 2.3.2 and 11.3, 2,4,6-TBP has been documented to occur naturally.
The median 2,4,6-TBP concentration present in control samples was significant when
compared to the median concentration in treated water samples. The difference between
background 2,4,6-TBP levels in the control water and treated water is 0.21 µg/L. As such,
the concentration modelled in MAMPEC was derived by subtracting the median control
concentration from the median treated ballast water concentration (Table 24). This approach
achieves a more realistic 2,4,6-TBP concentration in ballast water discharge as a result of
the BalPure® system and excludes 2,4,6-TBP apparently present in natural water.
As presented in section 2.3.1 above, bromoform is also a naturally produced chemical.
Because median bromoform concentrations in control samples were at low levels and not
considered significant when compared to treated sample median concentrations, the control
concentration was not subtracted from the treated ballast water samples for the purposes of
MAMPEC modelling.
Sodium bisulfite is added to ballast water discharge at an excess (median = 5 mg/L;
maximum = 8 mg/L) to ensure that all residual oxidants have been reacted (Tables 23 and 24).
As such, ballast water discharge may contain sodium bisulfite. To demonstrate that any
excess sodium bisulfite that may be present in ballast water discharge does not present
environmental risk, the median bisulfite concentration measured was evaluated with MAMPEC.
Table 25 below summarizes the Relevant Chemical concentrations and the associated
half-lives in water used for MAMPEC modelling.
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Table 25: Summary of Relevant Chemical Concentration and Half-life for Modelling
Highest Median
Half-life in
Reference/Comments
Discharge
Water
Concentration
Disinfection By-products (DBPs)
500 µg/L
0.3 days
EU RAR Sodium Hypochlorite (2007)
Substance
Bromoform
Dichlorobromomethane
0.98 µg/L
0.08 days
EU RAR Sodium Hypochlorite (2007)
Dibromochloromethane
21 µg/L
0.11 days
EU RAR Sodium Hypochlorite (2007)
Bromochloroacetic acid
13 µg/L
2.7 days
Hashimoto et al. (1998)
Monochloroacetic acid
1.08 µg/L
3.58 days
Hanson et al. (2002)
Monobromoacetic acid
14.5 µg/L
3.2 days
Hashimoto et al. (1998)
Dichloroacetic acid
1.15 µg/L
5.4 days
Hashimoto et al. (1998)
Dibromoacetic acid
50 µg/L
3.2 days
Hashimoto et al. (1998)
4.2 days
Hashimoto et al. (1998)
3.67 days
Hashimoto et al. (1998)
Tribromoacetic acid
Dibromochloroacetic acid
2,4,6-Tribromophenol
Sodium bisulfite
1
13.66 µg/L
1
8.8 µg/L
2
0.21 µg/L
1.21 days
Neutralization Chemical
5.0 mg/L
0.000747 days3
CICADS 66 (2005)
Yan et al. (2007)
1
= average concentration. See section 11.3 for calculation explanation.
= concentration in ballast water discharge after concentration in control sample subtracted.
3
= derived using a zero-order rate constant (Deltares, 2010).
2
11.8.3
Predicted Environmental Concentration results from MAMPEC modelling
The PEC values as a result of the two different MAMPEC modelling approaches used by
Deltares are presented below. Table 26 includes the PEC values for both Environment A
and the more conservative Environment B.
Table 26: PEC Summary for Environment A and Environment B
Substance
Bromoform
Dichlorobromomethane
Dibromochloromethane
Total THMs
Bromochloroacetic acid
Monochloroacetic acid
Monobromoacetic acid
Dichloroacetic acid
Dibromoacetic acid
Tribromoacetic acid
Dibromochloroacetic acid
2,4,6-Tribromophenol
Sodium bisulfite
PEC (µg/L)
Environment A
0.3190
0.0002
0.0057
0.3249
0.0236
0.0021
0.0272
0.0023
0.0939
0.0269
0.0169
0.0003
0.0133
PEC (µg/L)
Environment B
0.3810
0.0002
0.0059
0.3871
0.0646
0.0064
0.0799
0.0084
0.2757
0.0877
0.0525
0.0006
0.0133
The simulated environmental concentrations primarily depend on three aspects of the
modelling input: the substance emission (i.e. discharge concentration), the substance
characteristics (i.e. half-life), and the environmental conditions (harbour configuration,
flushing, etc.). For instance, the role of substance decay rates is evident when evaluating
TBAA and DBCM (Tables 25 and 26). The emissions for these two substances are in the
same order, but as the data indicate, Environment A PEC values differ by an order of
magnitude due to the difference in the decay rates of these substances (Deltares, 2010).
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The effect of varying environmental conditions can be seen when comparing the PEC values
for Environment A with Environment B. The "reduced flushing" in Environment B produces
larger PEC values for most substances, primarily for those with slower decay rates. This is
because removal of these substances from a harbour is more dependent upon flushing, and
flushing is reduced in the Environment B simulation. For unstable substances with rapid
decay rates, the reduced flushing in Environment B is less influential. This is because the
substances decay rapidly and disappear before the effect of flushing can be realized
(Deltares, 2010).
To ensure that the results obtained with the MAMPEC research version could be considered
sufficiently conservative, Deltares also generated PEC values with the last officially released
version of MAMPEC (version 2.5.04). Appendix B of the Deltares report provides PEC values
generated with MAMPEC version 2.5.04. For the most conservative environment in this
assessment (Environment B), the simulations with the research version produced PEC values
consistently higher than those obtained with version 2.5.04 (appendix B, Deltares, 2010).
Therefore, the research version of MAMPEC used in this assessment of the BalPure® system
can be considered more conservative (Environment B) and comparable to the standard
version of MAMPEC.
11.9
Effects on aquatic organisms
In this section, the available ecotoxicity data for each substance that had measurable
concentrations in ballast water discharge is evaluated and appropriate Predicted No Effect
Concentration (PNEC) values are derived. PNEC values for substances that were analysed
for, but not found with measurable concentrations in treated/neutralized ballast water
discharge, are not derived or considered. Tables 22 and 23 present the concentrations of
substances measured in ballast water discharge.
A thorough literature review of available acute and chronic aquatic ecotoxicity data for the
substances associated with the STDN system was conducted; the data are presented in
Tables 2 and 4. However, the data set is limited for many of the substances. In some cases,
data located in literature did not meet validity criteria and could only be used as supporting
information. This resulted in incomplete data sets for fish, crustaceans, and algae that
prevented individual PNEC derivation for all substances based on the guidance in the
Methodology (23 May 2008 version) as well as the EU Technical Guidance Document on
Risk Assessment (2003). Similar data gaps are also noted in other dossiers submitted for
Procedure (G9) approval, suggesting that other literature searches have had similar findings.
When a complete valid data set was located in literature, and/or any supporting data could
be identified, the reported toxicity values have been used for PNEC derivation. Where
available data is limited, the PNEC derivation approach used in the European Union Risk
Assessment Report (EU RAR) for Sodium Hypochlorite (2007) was followed.
Because the STDN system employs a neutralization step during deballasting, no
measureable concentration of TRO (as Cl2) is present in ballast water discharge. As TRO
(as Cl2) includes HOCl/OCl- and HOBr/OBr- these substances are therefore not considered
relevant with respect to PNEC derivation.
A PNEC value of 2.0 µg/L for 2,4,6-TBP was derived based on a complete chronic aquatic
ecotoxicity data set. The lowest chronic effect (NOEC) concentration located was 0.10 mg/L,
and because the chronic and acute data set was complete an assessment factor of 50 was
applied. This assessment factor and PNEC value is also reported in the CICADS 66 (2005)
document for 2,4,6-TBP.
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With respect to THMs, a complete valid acute toxicity data set was available for bromoform,
and two chronic endpoints (one fish, one alga) were available as supporting information.
Using the lowest acute effect concentration (12.3 mg/L) and an assessment factor of 1000,
results in a bromoform PNEC of 12.3 µg/L. The data sets for dibromochloromethane (DBCM)
and dichlorobromomethane (DCBM) were incomplete. One valid acute endpoint for fish and
one acute test with a ciliate was located for DBCM. No chronic studies for DBCM were
located. For DCBM, two acute endpoint studies with fish and one additional acute test with a
ciliate were located. No chronic endpoint studies for DCBM were located. It is beyond the
scope of the application process under Procedure (G9) to conduct chemical-specific testing
with these substances on a variety of organisms to complete the data set available in open
literature. This is particularly true considering that whole effluent toxicity (WET) testing
results of the ballast water discharge are available. Therefore, as an alternative to having
PNEC values that are non-derivable for DBCM and DCBM, the PNEC derivation approach
for THMs used in the EU RAR for Sodium Hypochlorite (2007) was utilized. For chloroform,
the EU RAR references an aquatic PNEC of 146 µg/L. The EU RAR presents that the data
collected in connection with an assessment for seawater chlorination "... suggest that the
ecotoxicities of the brominated THMs are not markedly different from chloroform"
(EU RAR, Sodium Hypochlorite, 2007). The EU RAR concludes that for the purposes of a
broad assessment, THMs can be regarded as having similar toxicities and applies the
chloroform PNEC to total trihalomethanes. Therefore, utilizing the EU RAR suggested PNEC
value of 146 µg/L for total THMs ensures that all THMs are considered, even in cases where
toxicity data is limited and individual PNEC values cannot be derived. To maintain a
conservative approach, the lower PNEC value for bromoform (12.3 µg/L) derived from the
available data can still be used for PEC/PNEC ratio evaluation.
For all HAAs, the database is incomplete with respect to chronic ecotoxicity endpoints. With
the exception one HAA, monobromoacetic acid (MBAA), the acute aquatic toxicity database
is also incomplete and did not allow for direct PNEC calculation for each individual HAA.
Again, it is beyond the scope of the application process under Procedure (G9) to conduct the
extensive amount of toxicity testing that would be required to complete the HAA data set.
This is particularly true considering that whole effluent toxicity (WET) testing results of ballast
water discharge are available. Therefore, the approach utilized in the Sodium Hypochlorite
EU RAR (2007) for PNEC derivation of HAAs was utilized. That is, the EU RAR considered it
"... conservative to treat all haloacetic acids simplistically as being TCAA ..." in regards to
PNECs and all HAAs could be considered to have a PNEC of 0.85 µg/L. Since this PNEC is
far lower than the PNEC of 500 µg/L that would be derived for TCAA based on the data
found in literature (acute data set in Table 2 and assessment factor of 1000), 0.85 µg/L is
very protective and seems to be a reasonable approach for this assessment.
For sodium bisulfite, the available aquatic toxicity data in literature was also limited.
No chronic endpoint studies were located, which is likely due to the rapid degradation
(minutes time scale) of sodium bisulfite. Two acute endpoints for fish were located along
with three acute endpoints for crustaceans. Since the submission of the Basic Approval
dossier, STDN commissioned a study (Nautilus, 2009) to determine the ecotoxicity of sodium
bisulfite to algae to complete the data set. Evaluating the completed data set, the lowest
acute effect was 81 mg/L sodium bisulfite (Daphnia magna). Using an assessment factor
of 1000, a PNEC value of 81 µg/L was derived. Table 27 below provides a summary of the
PNEC values derived.
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Table 27: PNEC Derivation Summary
Lowest Effect
Concentration
(mg/L)
Assessment
Factor
PNEC Value
(µg/L)
0.1
50
2.0
12.3
1000
12.3 / 146
Dibromochloromethane
(DBCM)
Insufficient Data
Located
--
Not Derivable
Dichlorobromomethane
(DCBM)
Insufficient Data
Located
--
Not Derivable
--
--
146
Bromochloroacetic acid
Insufficient Data
Located
--
0.85
Monochloroacetic acid
Insufficient Data
Located
--
0.85
Dichloroacetic acid
Insufficient Data
Located
--
0.85
Dibromochloroacetic
acid
Insufficient Data
Located
--
0.85
Monobromoacetic acid
Insufficient Data
Located
--
0.85
Dibromoacetic acid
Insufficient Data
Located
--
0.85
Tribromoacetic acid
Insufficient Data
Located
--
0.85
81
1000
81
Substance
Reference/Comments
Relevant Chemicals
2,4,6-Tribromophenol
21-day NOEC for Daphnia
magna; supported in
CICADS 66 (2005)
THMs
Bromoform
Total THMs
146 µg/L to be used as PNEC
for Total THMs
Use EU Sodium Hypochlorite
RAR suggested PNEC for
Total THMs
Use EU Sodium Hypochlorite
RAR suggested PNEC for
Total THMs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for Total THMs
HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Based on EU Sodium
Hypochlorite RAR suggested
PNEC for HAAs
Other Chemicals
Sodium bisulfite
Based on lowest acute effect;
no chronic data available.
Utilizing the PEC values obtained with MAMPEC modelling for two different environmental
configurations and the PNEC values derived from available toxicity data enables calculation
of PEC/PNEC ratios. The tables below show each PEC and PNEC value and the resulting
ratios for the two different emission scenarios modelled with MAMPEC.
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Table 28: PEC/PNEC Calculation for MAMPEC Environment A
Substance
PEC µg/L (Environ. A)
PNEC (µg/L)
PEC/PNEC
0.0003
2.0
0.00015
Bromoform
0.3190
12.3
0.02593
Dichlorobromomethane
0.0002
Not Derivable
--
Dibromochloromethane
0.0057
Not Derivable
--
0.3249
146
0.00222
Bromochloroacetic acid
0.0236
0.85
0.02776
Monochloroacetic acid
0.0020
0.85
0.00243
Monobromoacetic acid
0.0272
0.85
0.03200
Dichloroacetic acid
0.0023
0.85
0.00275
Dibromoacetic acid
0.0939
0.85
0.11047
Tribromoacetic acid
0.0269
0.85
0.03164
Dibromochloroacetic acid
0.0169
0.85
0.01988
0.0133
81
0.00016
Relevant Chemicals
2,4,6-Tribromophenol
THMs
Total THMs
HAAs
Other Chemicals
Sodium bisulfite
Table 29: PEC/PNEC Calculation for MAMPEC Environment B
Substance
PEC µg/L (Environ. B)
PNEC (µg/L)
PEC/PNEC
0.0006
2.0
0.00029
Bromoform
0.3810
12.3
0.03097
Dichlorobromomethane
0.0002
Not Derivable
--
Dibromochloromethane
0.0059
Not Derivable
--
0.3871
146
0.00265
Bromochloroacetic acid
0.0646
0.85
0.07600
Monochloroacetic acid
0.0063
0.85
0.00747
Monobromoacetic acid
0.0799
0.85
0.09400
Dichloroacetic acid
0.0084
0.85
0.00982
Dibromoacetic acid
0.2757
0.85
0.32435
Tribromoacetic acid
0.0877
0.85
0.10317
Dibromochloroacetic acid
0.0525
0.85
0.06176
0.0133
81
0.00016
Relevant Chemicals
2,4,6-Tribromophenol
THMs
Total THMs
HAAs
Other Chemicals
Sodium bisulfite
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For both Environment A and B, the highest PEC/PNEC ratio result was for DBAA
(0.11047 and 0.32435, respectively). All other ratios were well below 1, even when using
PEC values derived from the very conservative Environment B. Therefore, the data indicate
that all PEC/PNEC ratios are <1. According to section 7.3.2 of the Methodology
(23 May 2008), when no aquatic toxicity of the ballast water discharge is found through direct
testing, or the PEC/PNEC ratios are <1, no further assessment of direct toxic effects to the
aquatic environment is necessary.
11.10
Assessment of potential for bioaccumulation
Based on the data presented in this Final Approval dossier, as well as in the Basic Approval
dossier (MEPC 60/2/9) all of the substances associated with the BalPure® system have low
BCFs (<2000), indicating that they are unlikely to bioaccumulate in aquatic organisms or
present a significant food chain risk. With the exception of the THMs and 2,4,6-TBP, the
Active Substances and Relevant Chemicals have very low log Kows, which indicates the
compounds are hydrophilic. The THMs and 2,4,6-TBP, as would be expected, are
moderately hydrophobic. However, none of the THM log Kow values estimated and/or
located in the literature are ≥3 and none of the BCFs are ≥2000 (Table 19). For 2,4,6-TBP,
the reported log Kow is slightly above 3 (3.89); however, the BCF is less than 2000.
Therefore, bioaccumulation potential is low.
11.11
Effects on sediment
Based on the chemical and physical properties of all substances associated with the
BalPure® system presented in this Final Approval dossier, as well as in the Basic Approval
dossier (MEPC 60/2/9), no effects on sediment are anticipated (sections 3.4 and 5.2). The
only exception is 2,4,6-TBP with a Koc value of 1,186 L/kg (Table 6), which indicates a
moderate potential for partitioning into sediment. When 2,4,6-TBP is released to water, 93%
is expected to stay in the water compartment and 7% is transported to the sediment
compartment (OECD SIDS, 2003). This substance is also reported to dehalogenate rapidly
in anaerobic sediments, with a reported half-life of approximately 4 days (CICADS 66, 2005).
This is much more rapid than the sediment persistence criteria of 180 days in marine
sediment or 120 days in fresh water sediment (Table 19 and the Methodology, section 6.1.4).
Considering the low concentration of 2,4,6-TBP in ballast water discharge, a moderate
potential for sediment adsorption, and the rapid sediment degradation, no effects on
sediment are expected as a result of the BalPure® system.
11.12
Effects assessment
The data presented in this Final Approval dossier, as well as in the Basic Approval dossier
(MEPC 60/2/9), for the substances associated with the BalPure® system indicate that there is
a low potential for bioaccumulation and persistence in the aquatic environment, and moderate
potential for sediment adsorption for one substance (2,4,6 TBP). Moderate sediment
adsorption for 2,4,6-TBP poses low potential risk because the 2,4,6-TBP median concentration
discharged by the BalPure® system was only slightly more (0.21 µg/L) than the environmental
background level measured in the control (untreated water) samples. Further, 2,4,6-TBP is
readily biodegradable in anaerobic sediment (Table 16) and the 2,4,6-TBP concentration in
ballast water discharge is well below the lowest effect level for Daphnia magna (21-day NOEC
of 0.10 mg/L, Table 4).
No effects or risks in the form of secondary (food chain) poisoning or to sediment species are
anticipated. The information reviewed for degradation and bioaccumulation of the substances
related to the BalPure® system suggest that potential effects from these mechanisms cannot
be reasonably anticipated. As such, aquatic toxicity presents the most likely potential risk for
aquatic organisms.
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Tables 2 and 4 present aquatic toxicity data located in literature for a variety of species,
endpoints, and exposure periods. It is important to note that the effect concentrations for all
DBPs are notably higher than the measured concentrations of DBPs in ballast water discharge.
For instance, the overall lowest effect concentration located for all DBP substances is an acute
value of 0.028 mg/L (28 µg/L) for MCAA (Table 2). The highest concentration of MCAA
measured in ballast water discharge was 1.20 µg/L. As such, although aquatic toxicity
presents the most likely potential risk, one can reasonably conclude that the risk is low.
Further, as discussed in section 11.4 and below in section 11.13, the whole effluent toxicity
data confirms a low potential aquatic toxicity risk.
11.13
Comparison of effect assessment with discharge toxicity
As discussed in section 11.12 above, the effects assessment establishes that aquatic
toxicity, rather than bioaccumulation or sediment toxicity, presents the most likely potential
risk to aquatic organisms. However, the aquatic toxicity data for DBPs, when compared the
measured DBP levels in treated/neutralized ballast water discharge, suggests that aquatic
toxicity risks are low.
The low potential aquatic toxicity identified in the effects assessment is confirmed when
compared to whole effluent toxicity (WET) data for ballast water discharge from the BalPure®
system. The concentrations of DBP substances (µg/L range) in treated/neutralized discharge
are substantially lower than the aquatic effect concentrations found in literature (mg/L range).
Further, with the exception of testing with one species (Acartia tonsa), all WET tests after
neutralization with bisulfite resulted in E(L)C50 and/or NOEC values ≥100% ballast water sample.
The acute aquatic toxicity data for ballast water discharge presented in Table 3 suggest no
apparent ecotoxicity for all end points in five of six species tested (E(L)C50 and/or NOEC
values of ≥100% ballast water sample). For one species, Acartia tonsa, an effect was
observed in one of four acute tests with a low salinity sample (Day 1). In this sample, a
moderate effect was observed in the two highest test concentrations (100% and 32%
sample), resulting in a NOEC of 18% volume (Grontmij|AquaSense, 2009). This acute test is
considered an anomalous data point for several reasons. First, a total of eight ecotoxicity
tests (4 acute and 4 chronic) were performed with Acartia; only one acute test resulted in a
moderate effect. Second, during tests with Acartia moderate effects were also noted in a control
(untreated, NIOZ harbour water) sample (EC20 of 58% sample) (Grontmij|AquaSense, 2009).
A possible explanation for the moderate toxic effect in the treated and control samples is the
presence of Phaeocystis, an algal species known to be abundant in the NIOZ harbour and
which excretes allelochemicals. Although not a highly toxic algal species, the massive
blooms often result in ecosystem effects (Veldhuis and Kools, 2009). Phaeocystis was
present in the NIOZ harbour during the whole season of testing but was particularly abundant
during the first low salinity test cycles (Veldhuis and Kools, 2009), which corresponds with
when effects were observed in the Acartia tests.
In addition to the above points, it should be noted that STDN performed aquatic toxicity
testing with six taxonomic groups, rather than just the three required groups (algae,
crustacean, and fish). Both acute and chronic (sub-lethal) tests were performed. Further,
discharge toxicity was evaluated for two different salinities (high and low salinity) and at two
different time periods after treatment/neutralization (1 and 5 days). Treated/neutralized
ballast water discharge tests with all of the five other taxonomic groups under these variable
conditions were unaffected at 100% sample. These facts allow for increased confidence in
the conclusion that the 18% NOEC result for Acartia is an anomaly data point among 8 tests
with this species and the only one of six taxonomic groups having a moderate effect.
No toxic effects were observed in all other acute (Table 3) or chronic (Table 5) tests.
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Lastly, previous chronic ecotoxicity studies carried out for Basic Approval at the treatment
concentration of 15.0 mg/L HOCl resulted in no ecotoxicity (NOEC = 100% sample) in any of
the four species tested (MEPC 60/2/9, Table 5).
Considering all of the above information, although aquatic toxicity is identified as the most
likely potential for risk to aquatic organisms, discharge toxicity testing results suggest the
potential risk is extremely low.
12
RISK ASSESSMENT
The potential risks presented by having the BalPure® Ballast Water Management System
(BWMS) on board are discussed in section 12.1 and the potential risks to human health are
presented in section 12.2. Section 12.3 addresses risks to the aquatic environment.
12.1
Risk to safety of ship
Additional information regarding corrosion to that presented in the dossier for Basic Approval
submitted in August 2009 (MEPC 60/2/9) is presented in this section to address
recommendations and comments by the GESAMP-BWWG (MEPC 60/2/16, annex 7).
The additional data presented in this Final Approval dossier for sodium hypochlorite (or TRO
as Cl2) produced by the BalPure® system indicate that there is a low potential for corrosion of
the ballast water tanks.
12.1.1
Corrosion
The following information and evaluations making use of the GESAMP-BWWG
recommendations support that there is a low potential for corrosion of ballast water tanks due
to the effect of sodium hypochlorite (or TRO as Cl2).
An extensive search was conducted for published literature on the topic of sodium hypochlorite's
effect on corrosion in seawater. A review of these studies was conducted and the results are
discussed in the paper, "Effect of hypochlorite on the corrosion of carbon steel in ballast water
tanks" by Dr. Kenneth Hardee, Ph.D. and Prof. Giuseppe Faita, Ph.D. (appendix A.7, Hardee
and Faita, 2010). The authors generally confer that the corrosion risk would not be significantly
in excess of that for seawater alone in an existing corroded ballast water tank. Dr. Hardee
explains that by extrapolating data from Song, et al. (2009) for 5 mg/L chlorine, the corrosion
rate in the non-closed (flowing) system would be 0.104 mm/yr or only a 17% increase from that
of seawater alone. The corrosion rate will be much lower where there is existing rusted steel
and/or the system is closed (semi-stagnant) and has a specific chlorine demand similar to
applications with the STDN BalPure® BWMS. Kim, et al. (2009) further supports the calculations
that a ballast tank with 5 mg/L chlorine will have no more than a small effect on the corrosion
rate (appendix A.7, Hardee and Faita, 2010). Also the literature indicates that the corrosion
rate will slow as there is a buildup of surface rust on the steel, which restricts diffusion of the
hypochlorite to the metal surface, although the effect is very difficult to quantify.
In addition, the Hardee and Faita paper (appendix A.7) draws on corrosion and hypochlorite
chemistry, findings from the relevant published literature, and directly applies this to operating
data from land-based tests of the STDN BalPure® BWMS conducted at the Royal Netherlands
Institute for Sea Research (NIOZ), Texel, The Netherlands, and Maritime Environmental
Resource Centre (MERC), University of Maryland. The Hardee and Faita paper (appendix A.7)
presents and compares the corrosion rate of a carbon steel ballast water tank exposed to
hypochlorite as a closed system to the typical value for carbon steel structures fully immersed in
free flowing seawater. The paper indicates that the corrosion risk is not significantly in excess
of that for seawater alone. To further support the opinions regarding corrosion, STDN has
submitted the Hardee and Faita paper to BUREAU VERITAS, seeking third party verification.
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Ballast tank and pipe coating suppliers have conducted independent tests relating to the
impact of seawater and treated seawater on their coatings. Ameron, as one of these
coatings vendors, sees no effect with 5 mg/L chlorine in seawater on their coating as stated
in a letter to STDN (appendix A.7).
Per the German Administration's request, STDN has included Table 1 in appendix A.7, which
outlines point-by-point the recommendations for corrosion testing contained in document
MEPC 59/2/16 in column one and a response to what extent these guidelines were met in
the second column by the BMT (2004) study presented in the Basic Approval dossier.
We acknowledge that the information provided therein, though informative and germane to
corrosion of steel and coated steel in ballast water applications with chlorine, do not fully
meet the recommendations outlined in document MEPC 59/2/16. In consequence, and in
support of the conclusions of the paper by Dr. Kenneth Hardee and Prof. Giuseppe Faita that
corrosion risk is not significantly in excess of that for seawater alone, we have voluntarily
contracted Corrosion Testing Laboratories (CTL), Inc. to complete six months of corrosion
tests to fully meet the guidance contained in document MEPC 59/2/16 as recommended by
the Group. The results of the study will be considered as part of the Type Approval process
with the German Administration.
12.2
Risks to human health
As discussed in section 1.2, Severn Trent De Nora submitted an application dossier for Basic
Approval in August 2009 (MEPC 60/2/9). That dossier was reviewed during the 12th meeting of
the GESAMP-BWWG in December 2009 and Basic Approval was recommended. The Group
considered the human health risk assessment information "sufficient to allow the Group to
recommend Basic Approval" (comment 0.10) and "that the human exposure assessment
submitted by the Applicant makes possible to conclude that the operation of this BWMS poses
no unacceptable risk to ships' crew, technicians and to the general public" (comment 4.4.2).
However, as noted in the comments listed in section 1.2, a number of recommendations
were made as follows:
.1
The Group recommended to take into consideration the human exposure
during sampling of ballast water at discharge (inhalation, dermal contact),
as well as during periodic sediment cleaning (inhalation, dermal contact).
These scenarios should also be considered in the conceptual exposure
model (CEM).
.2
The Group recommended that the data sets on the analysis of Active
Substance, Relevant Chemicals and Other Chemicals in treated ballast water
should be further investigated during land-based and shipboard testing.
.3
The Group recommended that confirmation by further testing should be
performed, that there will be no unacceptable risks (to ship safety, human
health, or the environment) due to the chemical composition of the ballast
water treated by this BWMS.
The following subsections from the dossier for Basic Approval have been revised to consider
additional potentially affected receptor groups (ballast water samplers or persons removing tank
sediment). Differences in chemical composition of ballast water discharge based on land-based
testing results are compared to the previously reported level of sodium bisulfite and maximum
levels of bromate ion, THMs, and HAAs measured during studies of the BalPure® system
conducted by the University of Washington (Sosik and Herwig, 2009; as reported in Tables 27
to 29 of the application dossier for Basic Approval). Risks to receptors potentially exposed to
treated ballast water discharge are re-quantified using the land-based testing results.
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The evaluation presented herein supplements the evaluation presented in the application
dossier for Basic Approval in two ways: (1) risks for technicians or others who may be
exposed during ballast water discharge sampling are evaluated quantitatively, and (2) risks
to receptors previously evaluated for potential exposure to treated ballast water discharge
have been revised using the land-based testing results to estimate exposure.
12.2.1
Introduction
Quantitative human health risk assessments generally follow the process outlined below:
Step 1
Hazard
Identification
(Data Review/
COPC
Selection )
Step 2
Step 4
Step 5
Step 6
Review &
Assessment of
Toxicological
Data
Risk
Quantification
Uncertainties
Evaluation
Risk Assessment
Conclusions
Exposure
Assessment
Step 3
With respect to the potential human health risks associated with the BalPure® BWMS, Step 1
is the hazard identification process. The BalPure® operational system is reviewed, and
chemicals stored on the ship and added to the system or produced in situ at concentrations
potentially harmful to human health are carried forward in the quantitative risk assessment as
the chemicals of potential concern (COPCs). In Step 2, COPC-specific toxicity values for use
in the quantitative risk analysis are compiled via an exhaustive literature search. If no toxicity
data exists, information from appropriate surrogates and/or structurally similar chemicals may
be used. For COPCs without toxicity information, quantitative risk evaluation is not possible.
In Step 3, exposure scenarios are developed (1) to describe the potential exposures on
board during routine vessel operations including operation, monitoring and maintenance of
the BalPure® BWMS and (2) to describe the potential exposures on and off board during
equipment failure/and or accidental release of the COPCs, and (3) to provide a basis for
quantifying those exposures. Each exposure scenario addresses the COPCs, the potential
route or mechanism of exposure, and potentially exposed human populations (known as
"receptors"). When operation-specific data for scenario development are unavailable,
conservative values found in the appropriate regulatory guidance are used.
In Step 4, the toxicity and exposure assessments are integrated into quantitative expressions
of risks. This includes COPC-specific, multi-pathway risks for each of the potential receptors.
The risk values presented in a risk assessment are conditional estimates derived from a
considerable number of conservative, health-protective assumptions about exposure and
toxicity. Thus, to place the risk estimates in proper perspective, it is important to specify the
assumptions and uncertainties inherent in the risk assessment. This process is conducted in
Step 5. This step may also involve the reevaluation of data or the identification of additional
data requirements to decrease uncertainty. Step 6 involves the development and presentation
of conclusions that can be inferred from the findings of the risk assessment. This step
provides risk managers with insight into the interpretation of the risk assessment results.
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12.2.2
Hazard identification/chemical of potential concern selection
The chemicals of potential concern (COPCs) associated with the use of BalPure® BWMS
were selected by determining which chemicals, either stored and added to the system or
formed in situ, have the potential to adversely impact human health under either routine
operating conditions, maintenance operations, or during an emergency resulting in an
unexpected release.
As described in sections 1 and 2, the BalPure® BWMS is a nearly closed system that
produces the disinfection agent, sodium hypochlorite (as a mixture of hypochlorous
acid/hypobromous acid), via electrolysis of seawater. Hydrogen gas, a secondary by-product
of the in situ electro-chemical process, is vented to the atmosphere (using blowers) at
concentrations of less than 1%. However, exposure to atmospheric gases typically are not
included in risk assessment, and the safety features inherent in the BalPure® BWMS as well
as the physical properties of hydrogen gas suggest it is unlikely to accumulate to levels of
concern (e.g., above the LEL). Therefore, as indicated in section 2.3.3, hydrogen gas is not
considered relevant for the assessment of human health risks. Sodium bisulfite is added to
de-chlorinate the ballast water as it is discharged from the ship.
U PDATED TEXT P ERTINENT T O F INAL A PPROVAL A PPLICATION
In the application dossier for Basic Approval, the final list of COPCs carried forward in the risk
assessment included total residual oxidants (TRO) evaluated as hypochlorous acid, total THMs
(including chloroform, bromoform, bromodichloromethane, and chlorodibromomethane), total
HAAs (including bromochloroacetic acid, mono-, di- and trichloroacetic acids, and mono- and
dibromoacetic acids), bromate and sodium bisulfite. With respect to chemicals detected in
treated ballast water, this risk assessment for Final Approval is revised to evaluate only
chemicals detected during land-based testing.
As described in section 2.3, chemicals included for Basic Approval but not detected in the
land-based testing of the BalPure® system at NIOZ include chloroform, trichloroacetic acid,
and bromate ion. Chemicals detected during land-based testing of the BalPure® system at
NIOZ but not previously considered in the risk assessment are the HAAs tribromoacetic acid
and dibromochloroacetic acid, and 2,4,6-tribromophenol (TBP). The re-quantification of risks
presented in section 12.2.5 includes tribromoacetic and dibromochloroacetic acids in the total
HAA calculation.
As discussed in section 2.3.2, 2,4,6-TBP was not detected in measurable concentrations
in land-based tests using high salinity water (section 11.3, Tables 22 and 23).
2,4,6-Tribromophenol was detected at low levels (maximum = 1.3 µg/L) in ballast water
discharged during the low salinity test cycles, but also was detected in the untreated (control)
samples at the same, or higher, concentrations. 2,4,6-tribromophenol has been documented
to occur in natural environments, either as a pollutant from anthropogenic sources (wood
industry, antifungal use) or from natural production by marine benthic organisms (OECD
SIDS, 2003). Despite its detection in source (control) water, 2,4,6-TBP is added to the list of
COPCs carried forward in this risk assessment.
Chloroform was not detected in land-based discharge samples, and risks from exposure to
THMs will be evaluated based on the total concentration of all other THMs detected.
Bromate ion was not detected during land-based testing, and therefore has not been
considered as a COPC in this revised risk assessment.
I:\MEPC\61\2-9.doc
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Annex, page 53
12.2.3
Human Exposure Scenario
The US EPA (1989) defines an exposure pathway as "the course a chemical or pollutant
takes from the source to the organism exposed". An exposure route is "the way a chemical
or pollutant enters an organism after contact" (US EPA 1989). A complete exposure
pathway requires four key elements: chemical sources; migration routes (i.e. environmental
transport); potentially exposed human receptors; and routes of exposure to impacted media
(e.g., ingestion of chemicals in water). All four factors are required for a complete exposure
pathway; if any one factor is missing, the pathway is considered incomplete. Because an
incomplete pathway does not pose a potential health hazard, incomplete exposure pathways
are not included in this health risk assessment. Potential human receptor groups and
exposure routes are described below.
U PDATED TEXT P ERTINENT T O F INAL A PPROVAL A PPLICATION
The exposure scenarios evaluated quantitatively in the application dossier for Basic Approval
were: (1) STDN BalPure® BWMS Technicians exposed (via dermal contact and incidental
ingestion) to hypochlorous acid during maintenance activities and/or sodium bisulfite during
chemical resupply, (2) ship's crew/dock workers exposed (via dermal contact) to COPCs in
treated ballast water spray drift, and (3) the general public who may swim in the vicinity of
(and incidentally ingests and has dermal contact with) recently discharged ballast water
associated with the BalPure® system. However, the Group recommended the consideration
of exposure during sampling of ballast water at discharge (inhalation, dermal contact), as
well as during periodic sediment cleaning (inhalation, dermal contact), which has been added
to the discussion below.
12.2.3.1
Potential exposure pathways
The conceptual exposure model (CEM) provides the basis for a comprehensive evaluation of
the risks to human health by identifying the mechanisms through which people may be
exposed to COPCs. The CEM traces the COPCs in a logical migration from their sources
through various release mechanisms and exposure routes to potentially affected receptor
groups. The CEM identifies the exposure routes that are potentially complete under the
given use(s). These pathways are evaluated in the quantitative risk assessment for each
receptor. The CEM also facilitates the analysis and screening of exposure pathways not
likely to pose significant risks.
Primary, secondary, and tertiary sources of COPCs associated with the BalPure® BWMS are
listed in the CEM (Figure 3). The primary sources of COPCs include the in situ production of
sodium hypochlorite, the sodium bisulfite storage tanks and associated pipelines, and the
treated ballast water itself. Chemicals associated with the BalPure® BWMS are expected to
remain contained, unless a storage or pipeline failure occurs. Such a release would allow
COPCs to migrate to secondary and tertiary sources. For example, accidental spills and
pipe or tank failure could result in the release of COPCs onboard the vessel or to seawater.
From these secondary sources, the COPCs may migrate to tertiary sources such as
volatizing into air within enclosed spaces on the vessel or in outdoor air, or migration to
shorelines and/or docking areas.
As shown in Figure 3, only exposure to COPCs resulting from leaks of storage tanks,
pipelines and ballast tank discharges are evaluated quantitatively in this risk assessment.
This is because no exposure is anticipated during normal operating conditions, because
chemicals used in the BalPure® BWMS are contained within a closed system (hypochlorous
acid is produced in situ and is injected directly into the ballast system; sodium bisulfite is
injected into the ballast water as it is discharged from the ship), While both the chemical
I:\MEPC\61\2-9.doc
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Annex, page 54
storage tanks and ballast tanks are vented, vent lines are directed to the atmosphere or to
spaces within the ship with proper ventilation. Significant volatilization of COPCs from
solution (from either storage tanks or treated ballast water) into indoor or outdoor air is
extremely unlikely, and is not evaluated quantitatively. It is noted, however, that the
trihalomethanes produced as disinfectant by-products are volatile and hydrophobic, and as
such, could be inhaled near ballast water or vent air outlets. While this inhalation pathway is
not evaluated in the quantitative risk assessment, potential exposures and risks associated
with vent air during ballasting and deballasting were discussed in section 12.2.5.5 of the
application dossier for Basic Approval, and have been revised herein (now section 12.2.5.6)
to reflect maximum concentrations of THMs detected during land-based testing.
U PDATED TEXT P ERTINENT T O F INAL A PPROVAL A PPLICATION
As noted by the Group, exposure to treated ballast water also could occur during discharge
sampling. In addition, workers could be exposed to treated ballast water when cleaning
sediment from the tanks, although this activity would be conducted following established and
standard confined space safe entry practices, and persons engaged in this activity would be
wearing personal protective equipment (PPE).
These additional potential exposure
scenarios are considered in the risk assessment, as discussed below.
12.2.3.2
Identification of potentially exposed populations
The BalPure® system is designed to operate automatically, with the system processes during
ballasting and deballasting started and stopped based on electronic signals. Therefore,
under normal operating conditions, neither STDN BalPure® technicians nor the ship's crew is
expected to have contact with the BWMS-related COPCs. Because the BalPure® BWMS is
closed system, exposure to the Active Substance, disinfection by-products, or sodium
bisulfite is highly unlikely.
As shown in Figure 3, people with the greatest potential for exposure to BalPure®
BWMS-related COPCs are STDN BalPure® technicians involved in routine maintenance and
repair, or chemical resupply activities. These technicians, or others, could be exposed to
COPCs in treated ballast water during routine discharge sampling. Although unlikely, ship's
crew on board and in the spaces where the system components are present could also be
exposed to COPCs during a pipeline or chemical tank failure; it is anticipated that these
potential exposures would be less than those for STDN technicians conducting routine
maintenance or chemical resupply. Because ballast water tanks remain closed at all times
(with the exception of planned inspections/repairs of empty tanks) STDN technicians and the
ship's crew are not expected to have direct contact with treated ballast water, although this
potential exposure pathway is evaluated below. Further, either the ship's crew or dock
workers could have dermal contact with released ballast water as a result of spray drift.
As shown in Figure 3, while STDN technicians, ship's crew, or dock workers potentially could
inhale chemicals volatilizing from treated ballast water, these source-exposure pathways are
considered highly unlikely and are not evaluated quantitatively.
Others with potential for COPC contact include the general public recreating at beaches near
areas where treated ballast water has been discharged from the ship, although this exposure
scenario is highly unlikely. These receptors and the potential exposure pathways are
summarized below.
I:\MEPC\61\2-9.doc
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Annex, page 55
SOURCES
Secondary
Primary
Spills/Leaks from
Storage Tanks,
Pipelines or BWTS
Tertiary
Vessel Surface
Seawater
Release from
Ballast Tanks
Exposure Routes
On Board
STDN
STDN
Technician/Other Ship's Crew - Ship's Crew Technician Accidental
Ballast Tank
- Discharge
Maintenance
Release
Entry
Sampling
Off Board
Dock
Workers
General
Public
Dermal Contact/
Incidental Ingestion
•
X1
Vapors/Indoor Air
Inhalation
X
X
Vapors/Outdoor Air
Inhalation
X
X
X2
X
X
X
Dock/Shoreline
Dermal Contact/
Incidental Ingestion
X
•
•
X
•
•
•
Pathway is or might be complete; sufficient data available for quantitative evaluation
X
Pathway is or might be complete, but judged to be minor; not evaluated quantitatively
1
STDN Technician exposure considered worst-case scenario for anyone working onboard vessel.
2
Not evaluated quantiatively in risk assessment; semi-qualitatively evaluation provided.
Pathway is not complete; no evaluation required
Figure 3: Conceptual Exposure Model, BalPure® System
.1
STDN BalPure® BWMS Technicians: STDN technicians or properly
trained BalPure® personnel are the only receptors who would work directly
with the BWMS, including routine maintenance and chemical resupply of
sodium bisulfite, and therefore have the greatest potential for actual
exposure. Although proper chemical storage and handling, safety training,
and use of appropriate PPE would prevent direct contact with COPCs,
technicians could be exposed to hypochlorous acid, sodium bisulfite, or
treated ballast water during maintenance activities via:
-
incidental ingestion of COPCs during routine maintenance and
chemical resupply activities;
-
dermal contact with COPCs during routine maintenance and
chemical resupply activities; and
-
inhalation of COPC vapors or mists in air during routine
maintenance and chemical resupply activities.
The potentially complete and quantifiable exposure pathways for STDN
BalPure® technicians include: a) incidental ingestion of and dermal contact
with hypochlorous acid at maximum concentrations of 1,000 mg/L, and b)
incidental ingestion of and dermal contact with sodium bisulfite during
chemical resupply at maximum concentrations of 380,000 mg/L.
For hypochlorous acid, potential exposure is further mitigated by a pipeline
flushing cycle that is engineered into the system. For instance, after
generation of the Active Substances and the ballasting operation is
complete, a 10 minute cycle is initiated by the PLC to the electrolyzer cells
and injection pipelines with seawater. The same can be done for the
sodium bisulfite delivery piping when a deballasting operation is complete,
if needed to enhance the safety of an installation. These flush cycles
ensure that pipelines do not remain filled with chemicals when the BWMS is
not in operation.
I:\MEPC\61\2-9.doc
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Annex, page 56
.2
STDN BalPure® BWMS Technicians (or others) engaged in sampling of
treated ballast water: BalPure® technicians and/or ship's crew will likely
be responsible for sampling treated/neutralized ballast water at the point of
discharge. Although use of appropriate PPE would prevent direct contact
with COPCs, technicians could be exposed to COPCs in treated ballast
water during sampling via:
-
dermal contact with COPCs during discharge sampling; and
-
inhalation of COPC vapours or mists in air during discharge
sampling.
However, as discussed previously, during deballasting operations, residual
chlorine present in the ballast tank is neutralized (de-chlorinated) with
sodium bisulfite just prior to discharge from the ship. The trihalomethanes
are the only disinfectant by-products identified as volatile (see Table 17 of
this dossier and 18 in the dossier for Procedure (G9) Basic Approval), and
therefore could be inhaled near the ballast water discharge outlet. However,
it is anticipated that concentrations in air would be low and immediately mixed
into the surrounding atmosphere. Therefore, the only potentially complete
and quantifiable exposure pathway for ballast water samplers is dermal
contact with COPCs in discharged ballast water, including hypochlorous acid,
THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite at the maximum
residual ballast water concentrations detected during land-based testing:
<20, 0.845, 0.375, 0.0013, and 8.0 mg/L, respectively (see section 11.3 of
Basic Approval dossier and section 11.3 herein). It is also important to note
that treated ballast water discharge will be neutralized with sodium bisulfite,
so the maximum residual ballast water concentration for hypochlorous acid
is overly conservative because it does not consider neutralization. This
exposure scenario is similar to the ship's crew/dock worker scenario
included in the Basic Approval dossier (and described below), but would
not be accidental and is evaluated with possible greater frequency.
.3
Ship's crew: Under normal operating conditions, the ship's crew has limited
to no interaction with the BalPure® BWMS. The system and piping are
located in areas where the crew may be present, but normal ballasting and
deballasting modes of the BalPure® system are controlled automatically and
do not require chemical contact. However, this group has the potential to be
exposed to sodium bisulfite while chemical-resupply activities take place, or if a
pipeline or storage tank fails, or to any COPCs during a failure of the BalPure®
system. Exposure to treated ballast water is highly unlikely, since the tanks
are opened for required inspections only when empty, although the potential
for exposure to ballast water spray drift exists. The actual exposure potential
for this group is extremely low, but the possible exposure routes include:
-
incidental ingestion of the COPCs during an accidental release;
-
dermal contact with COPCs during an accidental release; and
-
inhalation of COPC vapors or mists in air during an accidental
release.
As previously indicated, accidental release of hypochlorous acid and/or
sodium bisulfite is expected to result in exposures smaller than those for
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Annex, page 57
STDN BalPure® technicians engaged in routine maintenance and chemical
resupply. Moreover, as described in section 8.1.3.2 of the application dossier
for Basic Approval, STDN technicians and ship's crew will be trained to
respond to sodium bisulfite spills; therefore these exposure scenarios are
not included in the quantitative risk assessment. The only potentially
complete and quantifiable exposure pathway for ship's crew is dermal
contact with COPCs in discharged ballast water, including hypochlorous
acid, THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite at the
maximum residual ballast water concentrations, as described above.
.4
Ship's crew (or others) responsible for ballast tank sediment cleaning:
Workers engaged in tank cleaning could be exposed to residual treated
ballast water remaining in the tanks (via dermal contact or incidental
ingestion, or to any vapours that remain in the tank once it has been opened).
However, because standard confined space entry protocols that are
required by applicable regulations will be implemented prior to tank entry,
this route of exposure is not considered complete. For instance, protocols
such as, but not limited to, those outlined by the International Association of
Classification Societies Ltd. (IACS) Confined Space Safe Practice (2007)
are performed as standard operating procedure prior to ballast tank entry.
For the purposes of example, these practices may include:
-
a safety meeting should be held prior to tank entry/survey;
-
Entry Permit should be obtained for the space to be entered;
-
identify the hazards and assess the risks;
-
evaluate ventilation of the space;
-
ensure that a standby and/or rescue team is in place;
-
check and evaluate gas measurements taken − as a
minimum, oxygen measurements should be carried out before
entry into the enclosed space;
-
use of personal gas measuring equipment during the
entry/survey; and
-
evaluate if special clothing and/or equipment are required.
Given the standard practices and mitigation measures implemented prior to
any ballast tank entry, the possibility of exposure to ballast water related
chemicals is very low. Therefore, as illustrated in the revised conceptual
exposure model shown in Figure 3, only the ballast water sampling scenario
has been added for quantitative evaluation in this risk assessment.
.5
Dock workers: Under normal operating conditions, dock workers will have
no interaction with the BalPure® BWMS or chemical resupply activities.
While exposure to treated ballast water is highly unlikely, the potential for
exposure to ballast water spray drift exists. The actual exposure potential
for this group is extremely low, but the possible exposure routes include:
-
I:\MEPC\61\2-9.doc
dermal contact with COPCs in ballast water spray drift.
MEPC 61/2/9
Annex, page 58
The only potentially complete and quantifiable exposure pathway for dock
workers is dermal contact with COPCs in discharged ballast water,
including hypochlorous acid, THMs, HAAs, 2,4,6-tribromophenol, and
sodium bisulfite at the maximum residual ballast water concentrations. This
quantitative evaluation is identical to that for ship's crew.
.6
General public: Although it is unlikely that the general public would
recreate near docked ships, it is possible that recreation areas could be
located downstream of shipping docks. While any COPC releases from the
ship would be immediately diluted into surrounding seawater, the general
public (adults or children) could be exposed to COPCs via:
-
incidental ingestion of ballast water COPCs discharged to
seawater near the shoreline;
-
dermal contact with ballast water COPCs discharged to
seawater near the shoreline; and
-
inhalation of ballast water COPC vapors or mists in outdoor air
near the shoreline.
The potentially complete and quantifiable exposure pathways for swimmers
include: incidental ingestion of and dermal contact with hypochlorous acid,
THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite in recently
discharged ballast water. It is conservatively assumed that maximum
residual ballast water COPC concentrations are diluted 100-fold prior to
contact with beachgoers.
In the application dossier for Basic Approval, the chemical composition of
treated ballast water was based on maximum levels of THMs and HAAs
measured during the studies of the BalPure® system conducted by the
University of Washington (Sosik and Herwig, 2009; as reported in Tables 27
to 29 of the Basic Approval dossier). Since that time, land-based testing
has been conducted, with the maximum concentrations shown in Tables 22
and 23. In regards to hypochlorous acid, the maximum treatment dose
(20 mg/L TRO as Cl2) presented in STDN's application dossier for Basic
Approval was also used in this human risk assessment to maintain a high
level of conservatism. However, the maximum treatment dose applied
during land-based testing was 15 mg/L TRO as Cl2. Because the human
risk assessment is performed using a 20 mg/L dose any risks due to
exposure of hypochlorous acid can be considered less than presented
here. Table 30 provides a summary of the exposure point concentrations
(EPCs) discussed above and used this risk assessment, and compares
them to the values used in the dossier for Basic Approval. Overall, there is
very little difference in the maximum concentrations of THMs and HAAs
between the two tests.
I:\MEPC\61\2-9.doc
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Annex, page 59
Table 30: Comparison of Basic Approval and Land-based Ballast Water Residual
COPC Exposure Point Concentrations
COPC
Hypochlorous Acid
Bromate
THMs
HAAs
2,4,6-Tribromophenol
Sodium bisulfite
NA =
*
=
12.2.3.3
Basic and Final
Approval
Dossiers STDN
Technicians:
Maximum
Concentration in
System
Basic Approval
Dossier
Maximum
Residual Ballast
Water
Concentrations
Land-based
Maximum
Residual Ballast
Water
Concentrations
Land-based
Diluted (100X)
Residual Ballast
Water
Concentrations
mg/L
1.00E+03
NA
NA
NA
NA
3.80E+05
mg/L
2.00E+01*
4.20E-02
1.10E+00
2.42E-01
NA
2.00E+00
mg/L
2.00E+01*
Not detected
8.45E-01
3.75E-01
1.30E-03
8.00E+00
mg/L
2.00E-01*
Not detected
8.45E-03
3.75E-03
1.30E-05
8.00E-02
Not applicable
Assumed as worst case residual; maximum treatment dose concentration
Quantitative exposure assessment
As described above, although highly unlikely, STDN BalPure® technicians could have direct
contact (ingestion and dermal contact) with COPCs within the BWMS during maintenance
activities and to sodium bisulfite during chemical resupply activities. STDN BalPure®
technicians or others could have dermal exposure to treated ballast water during discharge
sampling and ship's crew or dock workers could have dermal exposure to ballast water spray
drift. Beachgoers may recreate in the vicinity of ballast water discharges. Intake factors are
used to determine the amount of COPC that each receptor is potentially exposed to via each
exposure route, and are used to evaluate both cancer risk and non-cancer hazard.
The following equation was used to quantify intake from the dermal contact pathway:
Iw = (Cw)(SA)(PC)(CF)(ET)(EF)(ED) / (BW)(AT)
Where:
Iw
Cw
SA
PC
CF
ET
EF
ED
BW
AT
=
=
=
=
=
=
=
=
=
=
I:\MEPC\61\2-9.doc
intake from dermal contact with COPC in ballast water/solution (mg/kg-d)
maximum concentration of a COPC in ballast water/solution (mg/L)
skin surface area in contact with ballast water/solution (cm2/d)
dermal permeability coefficient (cm/hr), chemical-specific
conversion factor 10-3 (L/cm3)
exposure time (h/d)
event frequency (d/y)
exposure duration (y)
body weight (kg)
averaging time (d), ED x 365d/y (non-carcinogens),
70y x 365d/y (carcinogens)
MEPC 61/2/9
Annex, page 60
The following equation was used to quantify intake from the incidental ingestion pathway:
Iw = (Cw)(IngR)(EF)(ED) / (BW)(AT)
Where:
Iw
Cw
IngR
EF
ED
BW
AT
=
=
=
=
=
=
=
intake from incidental ingestion of COPC in ballast water/solution (mg/kg-d)
maximum concentration of COPC in ballast water/solution (mg/L)
ingestion rate (L/day)
event frequency (d/y)
exposure duration (y)
body weight (kg)
averaging time (d) - ED x 365d/y (non-carcinogens),
70y x 365d/y (carcinogens)
The receptor-specific exposure parameters used to estimate COPC intake based on the
equations above are summarized below and the resulting intake factors summarized in
Tables 31 and 32. As shown in Tables 31 and 32, the intake equations described above for
the general public (beachgoers) are age-adjusted to account for six years of exposure as a
child and 24 years of exposure as an adult. This approach is consistent with guidance
(US EPA 1989 and 1991e), and accounts for any differences in exposure assumptions
between children and adults.
.1
STDN Technicians
The adult exposure factors used to quantify potential exposure to
hypochlorous acid during maintenance of the BalPure® BWMS or to sodium
bisulfite during chemical resupply are:
I:\MEPC\61\2-9.doc
-
Ingestion Rate: While incidental ingestion is likely to be only
a fraction of the ingestion rate for swimming, 0.05 L/hour is
conservative and therefore used (US EPA 1989).
-
Skin Surface Area Available for Contact: During an
accidental spill, technicians or workers may have significant
contact with hands and arms, which results in a skin surface
area of 3,300 cm2 (US EPA 2004).
-
Permeability Constant: Chemical-specific; for inorganics
without a permeability coefficient, and especially for ionized
chemicals, guidance recommends using 0.001 cm/hour
(US EPA 2004).
-
Body Weight: The adult body weight typically applied in risk
assessment is 70 kg (US EPA 2002).
-
Exposure Time: The exposure time is assumed to
be 0.25 hours per event, is based on best professional judgment.
-
Event Frequency: Based on best professional judgment,
an exposure frequency of 1 spill event per year is used.
-
Exposure Duration: Based best professional judgment, the
exposure duration is 10 years.
MEPC 61/2/9
Annex, page 61
-
.2
Averaging Time: The life expectancy of 70 years (25,550 days)
was used as the averaging time for exposure to carcinogenic
contaminants (US EPA 2002).
The averaging time for
non-carcinogenic effects is equal to the exposure duration
of 10 years (3,650 days).
STDN BalPure® BWMS Technicians (or others) responsible for ballast
water discharge sampling
The adult exposure factors used to quantify potential exposure to
discharged ballast water during sampling are expected to be similar to
those used to quantify ship's crew/dock worker exposure to spray drift, with
the exception of a higher event frequency:
.3
-
Skin Surface Area Available for Contact: During sampling
of ballast water at discharge, crew or workers may have
limited contact with hands, arms, and face, which results in a
skin surface area of 1,800 cm2 which is based on best
professional judgment (10% of total body; US EPA 2004).
-
Permeability Constant: Chemical-specific; for inorganics
without a permeability coefficient, and especially for ionized
chemicals, guidance recommends using 0.001 cm/hour
(US EPA, 2004). The value for chloroform, 0.0068 cm/hour, is
used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol
(US EPA 2004).
-
Body Weight: The adult body weight typically applied in risk
assessment is 70 kg (US EPA, 2002).
-
Exposure Time: The exposure time is assumed to
be 0.25 hours per event, is based on best professional judgment.
-
Event Frequency: Based on best professional judgment, an
exposure frequency of 52 ballast water discharge sampling
events per year is used.
-
Exposure Duration: Based on best professional judgment,
the exposure duration is 10 years.
-
Averaging Time: The life expectancy of 70 years (25,550 days)
was used as the averaging time for exposure to carcinogenic
contaminants (US EPA, 2002). The averaging time for
non-carcinogenic effects is equal to the exposure duration
of 10 years (3,650 days).
Ship's Crew/Dock Workers
The adult exposure factors used to quantify potential exposure to
discharged ballast water spray drift are:
-
I:\MEPC\61\2-9.doc
Skin Surface Area Available for Contact: During a spray drift
incident, crew or workers may have limited contact with hands,
arms, and face, which results in a skin surface area of 1,800 cm2
which is based on best professional judgment (10% of total
body; US EPA 2004).
MEPC 61/2/9
Annex, page 62
.4
-
Permeability Constant: Chemical-specific; for inorganics
without a permeability coefficient, and especially for ionized
chemicals, guidance recommends using 0.001 cm/hour
(US EPA 2004). The value for chloroform, 0.0068 cm/hour, is
used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol
(US EPA 2004).
-
Body Weight: The adult body weight typically applied in risk
assessment is 70 kg (US EPA 2002).
-
Exposure Time: The exposure time is assumed to
be 0.25 hours per event, is based on best professional judgment.
-
Event Frequency: Based on best professional judgment,
an exposure frequency of 1 spray drift event per year is used.
-
Exposure Duration: Based on best professional judgment,
the exposure duration is 10 years.
-
Averaging Time: The life expectancy of 70 years (25,550 days)
was used as the averaging time for exposure to carcinogenic
contaminants (US EPA 2002).
The averaging time for
non-carcinogenic effects is equal to the exposure duration
of 10 years (3,650 days).
General Public (Beachgoers)
The exposure factors used to quantify potential exposure to COPCs in
discharged ballast water to swimming beachgoers (adults and children) are
described below. As discussed above and shown in Tables 31 and 32, the
intake factors used to evaluate cancer risk for beachgoers are age-adjusted
to account for differences in exposure assumptions between children and
adults.
I:\MEPC\61\2-9.doc
-
Ingestion Rate: The ingestion rate for swimming, 0.05 L/hour,
is used (US EPA 1989).
-
Skin Surface Area Available for Contact: The average of
the 50th percentile total skin surface area for adults
is 18,000 cm2 and for children is 6,600 cm2 (US EPA 2004).
-
Permeability Constant: Chemical-specific; for inorganics
without a permeability coefficient, and especially for ionized
chemicals, guidance recommends using 0.001 cm/hour
(US EPA 2004). The value for chloroform, 0.0068 cm/hour, is
used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol
(US EPA 2004).
-
Body Weight: The adult and child body weights typically
applied in risk assessment are 70 and 15 kg, respectively
(US EPA 2002).
-
Exposure Time: The US EPA's recommended swimming
duration of 60 minutes per event, based on the 50th percentile
value (US EPA 1997).
MEPC 61/2/9
Annex, page 63
-
Event Frequency: Based on best professional judgment, an
upper-end exposure frequency of 10 events per year is used.
-
Exposure Duration: Based on US EPA guidance, the
exposure duration is 30 years, which includes six years as a
child and 24 years as an adult (US EPA 2002).
-
Averaging Time: The life expectancy of 70 years (25,550 days)
was used as the averaging time for exposure to carcinogenic
contaminants (US EPA 2002).
The averaging time for
non-carcinogenic effects is equal to the exposure duration;
24 years as an adult (8,760 days) and 6 years as a child
(2,190 days).
Table 31: Summary of Dermal Intake Factors
IFdermal =
IFdermal/adj =
SA x PC x CF x ET x EF x ED
BW x AT
SAchild x PC x CF x ETchild x EFchild x EDchild +
BW child x AT
SAadult x PC x CF x ETadultx EFadult x EDadult
BW adult x AT
IFdermal = Dermal Intake Factor, L water/kg body weight-day
SA =
PC =
CF =
ET =
EF =
ED =
BW =
AT =
Surface Area, cm2
Dermal Permeability Constant, cm/hour
Volumetric Conversion Factor, 1 Liter/1000 cm3
Exposure Time, hours/day
Exposure Frequency, days/year
Exposure Duration, years
Body Weight, kg
Averaging Time, days
STDN
Exposure Variable Technician
STDN
Technician/Other - Ship's Crew/
Sampling
Dock Worker
General Public
Child
Adult
(0-6 years)
SA
3300
1800
1800
18000
6600
CF
0.001
0.001
0.001
0.001
0.001
ET
0.25
0.25
0.25
1
1
EF
1
52
1
10
10
ED
10
10
10
24
6
BW
70
70
70
70
15
ATcarcinogens
ATnonarcinogens
25550
3650
25550
3650
25550
3650
25550
8760
25550
2190
PATHWAY-SPECIFIC INTAKE FACTORS:
Chemical-Specific Intake Factors via Dermal Contact (IFdermal), L water/kg body weight-day
Carcinogens x PC
Noncarcinogens x PC
NA = Not applicable.
I:\MEPC\61\2-9.doc
4.61E-06
3.23E-05
1.31E-04
9.16E-04
2.52E-06
1.76E-05
3.45E-03
7.05E-03
NA
1.21E-02
MEPC 61/2/9
Annex, page 64
Table 32: Summary of Oral Intake Factors
IForal =
IForal/adj =
IForal =
IR =
ET =
EF =
ED =
BW =
AT =
Exposure
Variable
IngR x ET x EF x ED
BW x AT
IngRchild x ETchild x EFchild x EDchild + IngRadult x ETadultx EFadult x EDadult
BW child x AT
BW adult x AT
Oral Intake Factor, L water/kg body weight-day
Ingestion Rate, L/hour
Exposure Time, hours/day
Exposure Frequency, days/year
Exposure Duration, years
Body Weight, kg
Averaging Time, days
STDN
Technician
STDN
Technician/Other - Ship's Crew/
Sampling
Dock Worker
General Public
Child
Adult
(0-6 years)
IngR
0.05
NA
NA
0.05
ET
0.25
NA
NA
1
0.05
1
EF
1
NA
NA
10
10
ED
10
NA
NA
24
6
BW
70
NA
NA
70
15
ATcarcinogens
ATnonarcinogens
25550
3650
NA
NA
NA
NA
25550
8760
25550
2190
PATHWAY-SPECIFIC INTAKE FACTORS:
Chemical-Specific Intake Factors via Oral Ingestion (IForal), L water/kg body weight-day
Carcinogens
Noncarcinogens
6.99E-08
4.89E-07
NA
NA
NA
NA
1.45E-05
1.96E-05
NA
9.13E-05
NA = Not applicable
12.2.4
Health effects in humans
The objective of this section is to provide information regarding the potential for health risks
from exposure to chemicals potentially present in treated ballast water. Specifically, this
section describes how dose-response, or toxicity values, are established and used for
non-carcinogenic and carcinogenic COPCs. Because only the ingestion and dermal
exposure routes are evaluated quantitatively, this section focuses exclusively on oral toxicity
values (which are commonly used as surrogates for evaluation of dermal exposure).
12.2.4.1
Acute health effects
With the exception of 2,4,6-tribromophenol, all of the COPCs identified can be skin and eye
irritants as described in Table 9 of this dossier and the Basic Approval dossier. Unlike the
COPCs previously evaluated, 2,4,6-tribromophenol can be an eye irritant but it has not been
demonstrated to irritate the skin (see Table 9).
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Annex, page 65
With the exception of sodium bisulfite, all of the COPCs identified are generated in situ at
aqueous concentrations in the µg/L to mg/L range. These in situ generated COPCs are at
concentrations too low to cause serious eye and skin irritation. There may be some limited
potential for minor eye irritation if there is direct contact with ballast water, due to a
combination of the COPCs, salts, and other compounds which may be in the
ballast/seawater prior to treatment. Skin irritation is considered unlikely given the very low
concentrations of the COPCs. THMs are known to cause both skin and eye irritation when
present at much high concentrations than those present in situ in ballast water (IPCS 2004).
The one COPC which could represent an acute eye and skin hazard is the sodium bisulfite
solution stored on the vessel. The MSDS (Table 9 of the dossier for Basic Approval) clearly
states that contact with the 38% solution can cause eye and skin irritation. Appropriate PPE
should be used when working with this solution to minimize the potential for these acute
health effects, and only trained personnel should be handling the concentrated solution
(Mallinckrodt, 2006a).
The potential for acute irritation of the nose and throat upon inhalation is unlikely. The THMs
which are the most likely COPCs to volatize were considered in a separate inhalation
assessment in the dossier for Basic Approval (Table 39). The safe levels used in that
inhalation assessment, and updated here (section 12.2.5.6) are considered protective of
irritation of mucous membranes caused by volatile THMs (OSHA 2009).
The more critical endpoint for potential exposure to ballast water COPCs at low
concentrations are chronic health issues such as liver disease and cancer. These chronic
effects are fully addressed in the risk assessment.
12.2.4.2
Non-carcinogenic adverse health effects
For the non-carcinogenic effects of specific constituents, most regulatory agencies assume a
dose exists below which no adverse health effects will be seen (US EPA 1989). Below this
"threshold" it is believed that exposure to a chemical can be tolerated without adverse
effects. Adverse effects manifest only when physiologic protective mechanisms are
overcome by exposure to doses above the threshold. The reference dose (RfD), expressed
in units of milligrams per kilogram-day (mg/kg-d), represents the daily intake of a constituent
(averaged over a year) per kilogram of body weight that is below the effect threshold for the
constituent. It is assumed that non-carcinogenic exposure doses are not cumulative from
age group to age group over a lifetime of exposure (US EPA 1989). An RfD is specific to the
constituent, route of exposure, and duration over which the exposure occurs.
Agencies, most notably the US EPA, review all relevant human and animal studies for each
constituent and select the studies pertinent to the derivation of specific RfDs. Each study is
evaluated to determine the no-observable-adverse-effect level (NOAEL) or, if data are
inadequate for such a determination, the lowest-observable-adverse-effect level (LOAEL).
The NOAEL corresponds to the dose (mg/kg-d) that can be administered over a lifetime
without inducing observable adverse effects. The LOAEL corresponds to the lowest daily
dose (mg/kg-d) that can be administered over a lifetime that induces an observable adverse
effect. The toxic effect characterized by the LOAEL is referred to as the "critical effect"
(US EPA 1989).
To derive an RfD, the NOAEL (or LOAEL) is divided by uncertainty factors (alternatively
known as safety factors) to ensure protection of human health. Uncertainty factors are
applied to account for: (1) extrapolation of data from laboratory animals to humans
(interspecies extrapolation), (2) variation in human sensitivity to the toxic effects of a
constituent (intraspecies differences), (3) derivation of a chronic RfD based on a subchronic
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Annex, page 66
rather than a chronic study, and (4) derivation of an RfD from the LOAEL rather than the
NOAEL. A safety factor of 10 is typically applied for each of these uncertainties during the
development of the RfD. Thus, the safety factor for an individual COPC could be as high
as 10,000. In addition to these uncertainty factors, modifying factors between 0 and 10 may
be applied to reflect additional qualitative considerations (US EPA 1989).
12.2.4.3
Carcinogenic adverse health effects
The incremental lifetime cancer risk (ILCR) attributed to a carcinogen is calculated as a
product of the daily intake (mg/kg-d) and the cancer slope factor (CSF). The US EPA's
model of carcinogenesis assumes the relationship between exposure to a carcinogen and
cancer risk is linear over the entire dose range, except at very high doses (US EPA 1989).
This linearity assumes there is no threshold-of-exposure dose below which harmful effects
will not occur. Because of this, carcinogenic effects are considered to be cumulative across
age groups when considering lifetime exposures.
CSFs are upper-bound (95% upper confidence limit (UCL)) estimates of the increased
cancer risk per unit dose, in which risk is expressed as the probability that an individual will
develop cancer within his or her lifetime as the result of exposure to a given level of a
carcinogen. All cancers or tumours are considered whether or not death results. This
approach is inherently conservative because of the no-threshold assumption and the use of
the 95% UCL of the estimated slope of dose versus cancer risk.
To identify oral RfDs and slope factors, the studies and approaches described by the
US EPA in its Integrated Risk Information System (IRIS) were compared to the toxicological
information reported in section 4 (Tables 11 to 13) of both this dossier and the dossier for
Basic Approval. When no toxicity values are reported in IRIS, best professional judgment
was used to develop values based on the data reported in Tables 11 to 13 in both this
dossier and the dossier for Basic Approval.
12.2.4.4
Hypochlorous acid and hypobromous acid
The health effects associated with hypochlorite (salts of hypochlorous acids) have been
studied primarily as it relates to its use as a disinfectant in drinking water. While various
drinking water goals for disinfectants have been established by the US EPA, the World
Health Organization (WHO), and the European Union (EEC), only the US EPA has identified
an oral reference dose for chlorine: 0.1 mg/kg-day (US EPA 1994). This value, as reported
in IRIS, is based on based on the NOAEL of 14 mg/kg-day for rats exposed to chlorine in
drinking water for two years (NTP 1992a), as reported in Table 11 of the dossier for
Basic Approval (Chronic Mammalian Toxicity). The US EPA (1994) applies a composite
uncertainty factor of 100: 10 to account for interspecies extrapolation and 10 to account for
the protection of sensitive subpopulations.
No toxicological information was found for hypobromous acid, or the associated hypobromite
salts. As previously reported, hypobromous acid is believed to be similar in toxicity to its
chlorinated analogue, hypochlorous acid. Therefore, as indicated in the COPC selection
(section 12.2.2), the Active Substance in the BalPure® BWMS is evaluated qualitatively as
hypochlorous acid.
12.2.4.5
Total trihalomethanes
During land-based testing, the trihalomethane (THM) by-products detected in ballast water
included bromoform (tribromomethane), dichlorobromomethane, and chlorodibromomethane.
Although not detected in samples from land-based testing, chloroform is another THM for
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Annex, page 67
which toxicity data is available. The US EPA has identified oral reference doses for four of
these THMs in IRIS, with values ranging from 0.01 mg/kg-day (chloroform; US EPA 2001b)
to 0.02 mg/kg-day (bromoform [US EPA 1991a], dichlorobromomethane [US EPA 1991b],
and chlorodibromomethane [US EPA 1991c]). The lowest (and therefore most conservative)
value is from the study of beagles administered oral doses (15 or 30 mg/kg-day) of
chloroform in capsules for 5 days/week over 7.5 years for which a LOAEL of 15 mg/kg/day
for liver effects, as is reported in Table 11 (Chronic Mammalian Toxicity) of the dossier for
Basic Approval.1 The US EPA (2001b) derived the oral reference dose based on a modeled
low benchmark dose (BMDL10) of 1.0 mg/kg-day, and included a composite uncertainty factor
of 100: 10 to account for extrapolation from animal data to humans and 10 to account for
intrahuman variability (US EPA 2009).2
As reported in Table 13 "Summary of Data on Carcinogenicity" of the Basic Approval dossier
either IARC or the US EPA has classified each of the four THMs as "probable" or "possible"
human carcinogens. Based on the studies identified in Table 13 of the Basic Approval dossier,
US EPA, in IRIS, has derived oral slope factors for bromoform (7.3 x 10-3 per mg/kg-day;
US EPA 1991a), dichlorobromomethane (6.2 x 10-2 per mg/kg-day; US EPA 1991b), and
chlorodibromomethane (8.4 x 10-2 per mg/kg-day; 1991c)3. The highest value is the most
conservative, therefore the oral slope factor for chlorodibromomethane is used to evaluate
carcinogenic risks from THMs.
12.2.4.6
Total haloacetic acids
As described in section 2, haloacetic acid (HAA) by-products detected in ballast water discharge
during land-based testing included bromochloracetic acid, mono- and dichloroacetic acids, and
mono- and di- and tribromoacetic acids, and dibromochloroacetic. Of these, the US EPA (2003)
has identified an oral reference dose in IRIS for only dichloroacetic acid, however, this value is
based on a subchronic (90 day study), which is not optimal for the evaluation of chronic effects.
As described above, a chronic effects level can be developed based on the NOAELs or
LOAELs reported for chronic toxicity studies in Table 11 of the Basic Approval. In section 11.3
of this dossier, no reported NOAELs or LOAELs could be located for the additional
substances. The available NOAELs identified for HAAs in the Basic Approval tables range
from 3.5 mg/kg/day for monochloroacetic acid (EU 2005) to 40 mg/kg/day for trichloroacetic acid
(IPCS 2000a); all studies are based on effects on rodents, therefore a composite uncertainty
factor of 100 (10 to account for extrapolation from animal data to humans and 10 to account
for intrahuman variability) is appropriate for the determination of a reference dose from any of
these studies. The lowest (and therefore most conservative) NOAEL-based calculated value
is for monochloroacetic acid – 0.034 mg/kg/day. The LOAELs identified for HAAs range
from 2 mg/kg/day for dibromoacetic acid (NTP 2007) to 40 mg/kg/day for dichloroacetic acid
(IPCS 2000a); all studies are based on effects on rodents, therefore a composite uncertainty
factor of 1000 (10 to account for the use of a LOAEL instead of a NOAEL, 10 to account for
extrapolation from animal data to humans, and 10 to account for intrahuman variability) is
appropriate for the determination of a reference dose from any of these studies. The lowest (and
therefore most conservative) LOAEL-based value is for dibromoacetic acid – 0.002 mg/kg/day.
Because the LOAEL-based value results in the lowest reference dose, it is used to evaluate
non-carcinogenic risks from HAAs.
1
2
3
IRIS reference doses for bromoform and chlorodibromomethane are based on subchronic studies
associated with the same NTP studies (1989 and 1985, respectively) cited in Table 11 of the dossier for
Basic Approval. The IRIS reference dose for dichlorobromomethane is based on the NTP (1987) chronic
LOAEL of 25 mg/kg/d cited in Table 11 of the dossier for Basic Approval.
A similar oral reference dose resulted from the NOAEL/LOAEL approach.
USEPA has determined that while oral exposure to chloroform may cause cancer, the reference dose
of 0.01 mg/kg-day is considered to be protective against cancer risk.
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Annex, page 68
As reported in Table 13 (Summary of Data on Carcinogenicity) of this and the dossier for
Basic Approval only dichloroacetic acid, dibromoacetic acid, and trichloroacetic acid have been
classified as either "probable" or "possible" human carcinogens.4 However, IRIS includes oral
slope factors for only dichloroacetic acid (0.05 per mg/kg-day; US EPA 2003), therefore this
value is used to evaluate carcinogenic risks from HAAs. It is noted that while no cancer slope
factor has been developed for the remaining HAAs, the effects levels reported in Table 13 of
the dossier for Basic Approval are up to 20 times lower for dibromoacetic acid (≥ 4 mg/kg/day)
than those reported for dichloroacetic acid (84 mg/kg/day). Therefore, some uncertainty
exists in the carcinogenic evaluation of HAAs; specifically carcinogenic risks associated with
dibromoacetic acid, the dominant residual HAA measured in ballast water (see Tables 22
and 23) may be underestimated.
12.2.4.7
2,4,6-Tribomophenol
As shown in Tables 11 and 13, no long-term exposure or carcinogenic studies on brominated
phenols have been identified (CICADS 66 2005).
With respect to carcinogenicity,
2,4,6-tribromophenol has not been classified (NTP 2009, IARC 2009). However, given the
very low levels of 2,4,6-TBP detected (two orders of magnitude lower than other COPCs; see
Table 30) and the presence of this chemical in source water, any risks associated with this
chemical as a result of BalPure® BWMS are expected to be very low.
12.2.4.8
Sodium bisulfite
The US EPA has not developed an oral reference dose for sodium bisulfite inclusion in IRIS.
However, as reported in Table 11 "Chronic Mammalian Toxicity" in the application dossier for
Basic Approval, The Health Council of the Netherlands identified a NOAEL of 72 mg/kg-day
for rats fed up to 20,000 mg/L sodium bisulfite, based on local effects (blood in feces;
hyperplastic changes of gastric epithelium) (2005). In the absence of other information,
an oral RfD can be calculated by applying a composite uncertainty factor of 100, 10 to account
for interspecies extrapolation and 10 to account for intrahuman variability, to the NOAEL
(72 mg/kg-day). This results in an oral RfD of 0.72 mg/kg-day.
As reported in Table 13 "Summary of Data on Carcinogenicity" in the application dossier for
Basic Approval, sodium bisulfite is not classifiable as to its carcinogenicity, therefore no oral
cancer slope factor is available.
As shown in Table 33, reference doses were identified for all COPCs except
2,4,6-tribromophenol. Cancer slope factors are available for only THMs and HAAs; therefore
carcinogenic effects can be evaluated for only these three COPCs.
Table 33: Summary of Toxicity Criteria
Substance
Oral Cancer Slope Factor
(per mg/kg-day)
Oral Reference Dose (mg/kg/day)
Hypochlorous Acid
1.00E-01 (chlorine)
NC
THMs
1.00E-02 (chloroform)*
8.40E-02 (chlorodibromomethane)
HAAs
2.00E-03 (dibromoacetic acid)
5.00E-02 (dichloroacetic acid)
2,4,6-Tribromophenol
NC
NC
Sodium bisulfite
7.20E-01
NC
*
Although chloroform was not detected in the land-based testing of the Balpure® system, it was
identified as having the most conservative oral reference dose and to maintain the
health-protectiveness of the evaluation, is retained here.
NC = No criteria.
4
As indicated in Table 13, NTP (2009) reports “Clear evidence of carcinogenic activity” in animals for
bromochloroacetic acid.
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Annex, page 69
12.2.5
Risk characterization
Risk characterization, the final step in the risk assessment process, combines data from the
hazard identification, health effects assessment, and exposure assessment to estimate the
potential carcinogenic and non-carcinogenic effects of COPCs over the applicable duration of
exposure. Despite quantification, it is believed that the actual potential health risks are very
low because of the low potential of exposure to chemicals associated with the BalPure®
BWMS. Risks presented below should be considered worst-case estimates.
Risks presented herein differ from the application dossier for Basic Approval in two ways:
(1) risks for technicians or others who may be exposed during ballast water discharge
sampling are evaluated quantitatively, and (2) risks to receptors previously evaluated for
potential exposure to treated ballast water discharge have been revised using the land-based
testing results to estimate exposure.
12.2.5.1
Acceptable risk levels
The risk that is acceptable is very much dependent on site-specific characteristics that
include: the number of people potentially exposed, the likelihood of exposure, the chemicals
driving the risk, and the decisions of risk managers. The incremental lifetime cancer risk
(ILCR) is compared to a range of acceptable probabilities to determine whether the potential
risk poses an unacceptable health threat. The US EPA directive, Role of the Baseline Risk
Evaluation in Superfund Remedy Selection Decisions (US EPA 1991a), states that action is
generally not warranted at a site when the cumulative carcinogenic risk for current and future
land use is less than 1 x 10-4 and the cumulative non-carcinogenic hazard index (HI) is less
than 1.0. The level of non-cancer hazard concern increases as the HI increases above unity,
although the two are not linearly related (US EPA 1989). The US EPA uses a potential
excess individual lifetime cancer risk of 1 x 10-6 (1 in 1,000,000) as a point of departure for
risk management actions.
12.2.5.2
Quantitative estimate of potential risks to STDN BalPure® technicians
Table 34 summarizes the risks quantified for the BalPure® Technician who may be exposed
to concentrated hypochlorous acid (generated concentration of 0.1%) during maintenance
activities or to the 38% sodium bisulfite solution during chemical resupply. Neither
hypochlorous acid nor sodium bisulfite is classifiable with respect to carcinogenicity,
therefore cancer risks are not reported below. The non-cancer hazard of 0.3 is well below
the level of concern (1.0); use of personal protective equipment (PPE) and safe chemical
handling procedures will further reduce any potential exposures and associated effects.
Table 34: Summary of Cancer Risks and Non-cancer Hazards for
BalPure® Technicians
Cancer Risk
Ingestion
Dermal
NC
NC
NC
NC
Substance
Hypochlorous Acid
Sodium Bisulfite
TOTAL
NA = not applicable, NC = no criteria.
I:\MEPC\61\2-9.doc
Total
NA
NA
NA
Non-cancer Hazard
Ingestion
Dermal
0.0049
0.00032
0.26
0.017
Total
0.0052
0.28
0.3
MEPC 61/2/9
Annex, page 70
12.2.5.3
Quantitative estimate of potential risks to STDN BalPure® technicians
(or others) during ballast water discharge sampling
Table 35 summarizes the risks quantified for the BalPure® Technician, or other worker, who
may be exposed to COPCs in ballast water during discharge sampling, based on land-based
testing maximum COPC concentrations. Hypochlorous acid, 2,4,6-tribromophenol, and sodium
bisulfite are not classifiable with respect to carcinogenicity, therefore cancer risks are reported
for only THMs and HAAs. The total estimated cancer risk of 8 x 10-8 (8 in 100,000,000) is far
below the US EPA point of departure of 1 x 10-6 (1 in 1,000,000). The total non-cancer
hazard, 0.002, is several orders of magnitude below the target level of 1.0.
Table 35: Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians
(or others) – Ballast Water Discharge Sampling
Substance
Hypochlorous Acid
THMs
HAAs
2,4,6-Tribromophenol
Sodium Bisulfite
TOTAL
Ingestion
NA
NA
NA
NA
NA
Cancer Risk
Total
Dermal
NC
NA
6.3E-08
6.3E-08
1.7E-08
1.7E-08
NC
NC
NC
NC
8E-08
Non-cancer Hazard
Total
Ingestion
Dermal
NA
0.00018
0.00018
NA
0.00053
0.00053
NA
0.0012
0.0012
NA
NC
NC
NA
0.000010
0.000010
0.002
NA = not applicable, NC = no criteria.
12.2.5.4
Quantitative estimate of potential risks to ship's crew or dock workers
Table 36 summarizes the risks quantified for ship's crew or dock workers who may be
exposed to COPCs in ballast water from spray drift, based on land-based testing maximum
COPC concentrations. Hypochlorous acid, 2,4,6-tribromophenol, and sodium bisulfite are
not classifiable with respect to carcinogenicity, therefore cancer risks are reported for only
THMs and HAAs. The total estimated cancer risk of 2 x 10-9 (2 in 1,000,000,000) remains
essentially unchanged from that estimated in the Basic Approval dossier, and is far below the
US EPA point of departure of 1 x 10-6. The total non-cancer hazard, 0.00004, is only slightly
higher than reported in the previous risk assessment and remains many orders of magnitude
below the target level of 1.0.
Table 36: Summary of Cancer Risks and Non-cancer Hazard
for Ship's Crew/Dock Workers
Substance
Hypochlorous Acid
THMs
HAAs
2,4,6-Tribromophenol
Sodium Bisulfite
TOTAL
Ingestion
NA
NA
NA
NA
NA
NA = not applicable, NC = no criteria.
I:\MEPC\61\2-9.doc
Cancer Risk
Total
Dermal
NC
NA
1.3E-09
1.2E-09
3.2E-10
3.2E-10
NC
NC
NC
NC
2E-09
Ingestion
NA
NA
NA
NA
NA
Non-cancer Hazard
Total
Dermal
0.0000035
0.0000035
0.000010
0.000010
0.000023
0.000023
NC
NC
0.00000020
0.00000020
0.00004
MEPC 61/2/9
Annex, page 71
12.2.5.5
Quantitative estimate of potential risks to the general public (beachgoers)
Table 37 shows cancer risks to beachgoers who may swim in the vicinity of recently
discharged ballast water associated with the BalPure® BWMS, based on land-based testing
maximum COPC concentrations (assumed to be instantly diluted 100-fold). Hypochlorous
acid, 2,4,6-tribromophenol, and sodium bisulfite are not classifiable with respect to
carcinogenicity, therefore cancer risks are reported for only THMs and HAAs. The total
estimated cancer risk is very low at 3 x 10-8 (3 in 100,000,000), is slightly lower than estimated
in the Basic Approval dossier and is far below the US EPA point of departure of 1 x 10-6.
Table 37: Summary of Cancer Risks for the General Public
Substance
Hypochlorous Acid
THMs
HAAs
2,4,6-Tribromophenol
Sodium Bisulfite
TOTAL
Ingestion
NC
1.0E-08
2.7E-09
NC
NC
Cancer Risk*
Total
Dermal
NC
NA
1.7E-08
2.7E-08
4.4E-09
7.1E-09
NC
NC
NC
NC
3E-08
Cancer risk is age-adjusted, assuming 6 years of exposure as a child
and 24 years as an adult.
NC = no criteria.
Non-cancer hazards for the general public, which are summarized in Table 38, also are very
low; 0.0007 for children and 0.0002 for adults. Although slightly higher than reported in the
Basic Approval dossier, these non-cancer hazards remain many orders of magnitude below
the target level of 1.0.
Table 38: Summary of Non-cancer Hazards for General Public
Substance
Hypochlorous Acid
THMs
HAAs
2,4,6-Tribromophenol
Sodium Bisulfite
TOTAL
Adult Non-cancer Hazard
Total
Ingestion
Dermal
0.000039
0.000014
0.000053
0.000017
0.000040
0.000057
0.000037
0.000090
0.00013
NC
NC
NC
0.0000022
0.00000078 0.0000030
0.0002
Child Non-cancer Hazard
Total
Ingestion
Dermal
0.00018
0.000024
0.00021
0.000077
0.000069
0.00015
0.00017
0.00015
0.00033
NC
NC
NC
0.000010
0.0000013
0.000012
0.0007
NC = no criteria
12.2.5.6
Semi-quantitative evaluation of potential risks from inhalation
The risk estimates reported in Tables 34 to 38 do not include inhalation of COPCs in indoor
or outdoor air. While significant volatilization of COPCs from ballast water into indoor or
outdoor air is not anticipated, some exposure to COPCs in air could occur. The most likely
operation that could result in exposure to COPCs in air is during ballasting, when air in the
ballast tanks is vented to the atmosphere as water is brought into the tanks. If the ship's crew
is present during this operation, they could be exposed to residual THMs in vent air, since
these disinfection by-products are both volatile and hydrophobic. Although concentrations of
THMs in vent air have not been measured, worst-case estimates of air concentrations can be
made based on maximum ballast water THM concentrations (see section 11.3) and the
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appropriate Henry's Law constants (the ratio of the aqueous-phase concentration of a chemical
to its equilibrium partial pressure in the gas phase). Because vent air will be immediately mixed
into the surrounding atmosphere, the air concentration estimates are also adjusted for dilution
into ambient air by dividing by a factor 10. As a conservative evaluation of the inhalation
exposure pathway, Table 39 summarizes these data (updated to reflect land-based test
results), and compares the revised estimated air concentrations to U.S. OSHA Permissible
Exposure Levels (PELs).
Table 39: Estimated Concentrations of THMs in Vent Air
and Comparisons to PELs
Basic Approval
Dossier
Maximum
Residual
Ballast Water
Concentration
(µg/L)
Final Approval
Dossier
Maximum
Residual
Ballast Water
Concentration
(µg/L)
Henry's
Law
Constant
(unitless)
THMs
Bromoform
1050
810
0.0218
Chloroform
53
Not detected
0.150
157
33
0.0320
90
1.5
0.0654
Substance
Chlorodibromomethane
Dichlorobromomethane
Final
Approval
Dossier
Estimated
Conc. in
Air
3
(mg/m )*
Air
Exposure
Limit
3
(mg/m )**
Air
Concentration
Exceeds
Exposure Limit?
5
No
240
No
0.11
NA
NA
0.0098
NA
NA
1.8
Not
detected
NA = Not Available.
*
Estimated based on Henry's Law constant at 25°C, and divided by a factor of 10 for dilution into ambient air.
**
U.S. Department of Labor, 2009. Occupational Health and Safety Administration, Permissible Exposure
Limits (PEL).
Actual air exposures will depend on proximity to vent outlets, atmospheric conditions (wind),
as well as the duration of ballasting. Because the THMs in vent air would quickly dissipate
into the atmosphere, it is anticipated that air exposures will decrease as distance to the
ballast water increases; therefore potential air exposures for dock workers and the general
public would be even less than those for the ship's crew. Based on this assessment of THMs
in vent air as a result of concentrations in ballast water, there is no evidence for the potential
of adverse health effects to the ship's crew, dock workers, or the general public.
12.2.6
Risk assessment conclusions
Overall risk findings from the application dossier for Basic Approval remain unchanged: the
health risks to all receptors from the BalPure® BWMS under normal operating conditions are
very small and well within acceptable levels. Even an STDN technician, exposed to
concentrated sodium bisulfite during a spill during chemical resupply, and who is wearing no
PPE – an unlikely scenario – would have low health risk. Cancer risk and non-cancer
hazards for the general public/beachgoers are well below levels of concern; actual risks to
these receptors are expected to be even lower, as they are unlikely to be repeatedly exposed
to treated ballast water as assumed in this risk evaluation. Since the risk assessment only
evaluated direct exposure via ingestion and dermal contact with chemicals or ballast water,
as these were considered the most relevant pathways, further semi-qualitative evaluation of
the inhalation pathway was performed for the volatile THMs. This assessment demonstrated
that conservative concentrations of airborne THMs generated by a release of ballast water
were well below occupational exposure limits.
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12.3
Risks to the aquatic environment
Potential risk to the aquatic environment as a result of the BalPure® BWMS was evaluated in
several regards. The substances potentially present in treated/neutralized ballast water
discharge were evaluated with respect to aquatic ecotoxicity, bioaccumulation potential and
environmental persistence and the whole effluent was evaluated for discharge ecotoxicity.
The Basic Approval dossier (MEPC 60/2/9) presented data from pilot scale studies, while this
document presents data generated during land-based testing of the full commercial scale
BalPure® system. Additionally, emission scenarios were simulated using the MAMPEC model
to generate meaningful PEC values to allow for a risk assessment with the PEC/PNEC ratio
method.
Direct ecotoxicity evaluation of whole effluent from the BalPure® system indicates that the
potential risks to the aquatic environment are very low. The acute and chronic WET testing
data indicate that 100% whole effluent did not have toxic effects on five of the six species
tested (Tables 3 and 5). For one species, Acartia tonsa, an effect was observed in one of
four acute tests with a low salinity sample. In this sample, a moderate effect was observed in
the two highest test concentrations (100% and 32% sample), resulting in a NOEC of 18%
volume (Grontmij|AquaSense, 2009). It is important to note that during tests with Acartia
moderate effects were also noted in a control (untreated, NIOZ harbour water) sample
(EC20 of 58% sample) (Grontmij|AquaSense, 2009). As explained in sections 11.4 and 11.13
above, a possible explanation for the moderate toxic effect in the treated and control samples
is the presence of Phaeocystis, an algal species known to be abundant in the NIOZ harbour
and which excretes allelochemicals. All other acute and chronic tests with Acartia, as well as
the five other species tested, demonstrate that 100% whole effluent sample had no toxic
effect, indicating that the NOEC of 18% (Table 3) is an outlying data point.
The conclusion of low potential risk to the aquatic environment is supported by the results of
worst-case discharge scenarios simulated with the MAMPEC model. By employing the
modelling approach described in section 11.8.1, it is important to note the layers of conservatism
applied. First, MAMPEC assumes continuous discharges (leaching from antifoulants), rather
than intermittent discharges (ballast water). Second, the physical dimensions of the "OECD
Commercial Harbour" configuration are smaller and tidal flushing is less, yet the ballast water
discharge rate for the whole Port of Rotterdam was used. Environment B builds onto the
worst case emission scenario with a smaller tidal exchange flow rate, minimizing the harbour
exchange percentage due to flushing. These elements result in overly conservative, rather than
realistic, PEC values. Lastly, in derivation of PNEC values the lowest effect concentrations and
highest appropriate assessment factors have been used (see section 11.9). All PEC/PNEC
ratios, even when calculated using PEC values generated in the very conservative "reduced
flushing" Environment B, are well below 1 and can be considered as protective of the aquatic
environment. Therefore, no further assessment of direct toxic effects is necessary as risks to
the aquatic environment are not expected from the use of the BalPure® system.
13
ASSESSMENT REPORT
The substances associated with the BalPure® system were evaluated for a variety of
endpoints, including ecotoxicity, bioaccumulation, and persistence in the environment.
Additionally, STDN's application dossier for Basic Approval (MEPC 60/2/9) included a full
assessment (including ship safety and human health) with respect to the onboard storage of
sodium bisulfite and the onboard generation of sodium hypochlorite. During the assessment
of potential risks related to the BalPure® system, a variety of reputable sources were
consulted to gather test data and conduct the assessments required. These sources include,
but are not limited to the WHO, IPCS, OECD and US EPA. Information was also gathered
from published independent research, which in most cases is peer-reviewed by others with
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Annex, page 74
similar levels of expertise. Further, reputable laboratories that utilize recognized testing
methods and appropriate quality control measures were commissioned for the toxicological
and analytical evaluations of ballast water discharge. Based on these facts, the level of
uncertainty associated with this assessment is low.
Aquatic toxicity was established as being the most likely potential risk to the aquatic
environment. Because TRO (as Cl2) is neutralized prior to discharge, the DBPs potentially
present in treated/neutralized ballast water discharge are the most important to consider for
this evaluation. In regards to aquatic ecotoxicity, the existing database for chronic endpoints
is limited for many of the THMs and HAAs. As such, the acute database, which is more
complete, was utilized for some substances. The evaluation of the chemical and physical
properties of all chemicals relevant to the BalPure® system suggests that bioaccumulation,
sediment adsorption, or environmental persistence is not expected to occur. Further, none of
the chemicals met all three criteria to be classified as PBT substances.
Whole effluent toxicity (WET) testing was performed with treated/neutralized samples drawn
from the land-based test set-up. With the exception of one acute test with Acartia tonsa, all
other acute and chronic discharge toxicity tests indicate no aquatic toxicity. Because only
one in eight tests with Acartia indicated moderate toxicity, and toxic effects were also
observed in a control sample during testing with this species, the NOEC of 18% sample was
likely to have been caused by compounds excreted by the algal species Phaeocystis.
All other tests for the five remaining species of aquatic organisms resulted in effect
concentrations of ≥100% sample.
Lastly, two different emission scenarios (Environments A and B) were simulated with MAMPEC
using the median DBP concentrations in ballast discharge. The resulting PEC values allowed
for calculation of PEC/PNEC ratios to estimate aquatic risk. All calculated ratios for the
substances measured in ballast water discharge are well below 1. Based on this assessment,
no potential risks as a result of ballast water discharge from the BalPure® system are anticipated.
14
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