Adverse Effects of Hydrocarbons
Found in Crude Oil
in the Marine Environment
John S. French, PhD
Pegasus Environmental Solutions – Alaska
PO Box 1470
Seward, AK 99664-1470
NW Tribal Water Rights Conference, October 2014
Anchorage, Alaska
[email protected]
907-491-0343
Who I am
John S. French, PhD
Biochemist & Environmental Toxicologist
Retired Professor from UAF – School of Fisheries
and Ocean Sciences
EVOSTC – Public Advisory Committee, Science
& Technology Representative
PWS – Regional Citizens’ Advisory Council,
•Past Board Member representing City of
Seward
•Past Chair Oil Spill Prevention and Response
Committee
•Past Member Scientific Advisory Committee
Member American Chemical Society & Society of
Environmental Toxicology and Chemistry
What do we need to protect in the
event of an oil spill?
A crucial first step is understanding the complex
interactions between the ocean, the environment and
specific ecosystems before deciding whether to
hammer them with oil spill counter measures.
What do we need to protect in the
event of an oil spill?
A crucial first step is
understanding the complex
interactions between the ocean,
the environment and specific
ecosystems before deciding
whether to hammer them with
oil spill counter measures.
Ocean Physics: The dynamic properties of
the oceans which drive the distribution on
nutrients within marine ecosystems, thereby
influencing both primary and secondary
production within those systems.
Environmental Dynamics: The bioenergetics
and trophic interactions among species within
the context of an ecosystem
Upwelling from deep ocean currents
provide most of the nutrients
necessary for life both near-shore
and off-shore in the Gulf of Alaska,
Bering and Chukchi Seas.
Primary Productivity in North Pacific
Measured as chlorophyll by Vertically Generalized Production Model
by calendar month (mean mgC/m2/day)
Primary Productivity in Gulf of Alaska
Calculated from Sea WiFS data for June 1999
Rivers
&
Lakes
Rivers
&
Lakes
Surface
Deep Ocean
Bottom-Up Driven
Ecosystem
(Gulf of Alaska)
Surface
Deep Ocean
Onshore-Off Driven
Ecosystem
(Gulf of Mexico)
The high benthic biomass (>300 g m-2) and chlorophyll
(>150 mg m-2) on the Chukchi Sea Shelf are known
centers for deposition of reduced organic matter
orginating on the Bering Sea shelf and carried north by
the Anadyr and Bering Currents.
Unlike salt marshes and other shorezone spawning and nursery
grounds for on-shore off driven ecosystems, There may be
substantial annual variation in the locations of these grounds in
bottom-up driven ecosystems
Spawning migration
Adult Population
Movement to offshore
feeding areas
Immature
Population
Spawning Site
Migration in plankton
Nursery Area
Most environmental regulations
in the United States assume that a
substance is NOT toxic unless it
has been PROVEN to be toxic
beyond reasonable doubt.
Crude oil is complex mixture
containing thousands of discrete
compounds. Recent mass spectral
studies report there may be more
than 50,000 compounds of the
general structure CcHhNnOoSs. The
absolute structures of only a few
hundred are known. Less than 1/3
of those have been rigorously tested
for toxicity to the environment.
Elemental Composition of Crude Oils
These are the ranges commonly seen in crude oils
A common fractionation of crude oils is by
fractional distillation into Saturates, Aromatics,
Resins and Asphaltenes (SARA)
Further solvent extrations can separate the Resins
and Asphaltenes into polar and non-polar
subfractions.
Examples of Chemical Classes, Names, & Typical Compounds
From Fingas, 3012
Not knowing the toxicological
properties of crude oil
constituents does NOT mean that
they are safe!
Precautionary Approach
“In order to protect the environment, the
precautionary approach shall be widely applied
by States according to their capabilities. Where
there are threats of serious or irreversible
damage, lack of full scientific certainty shall not
be used as a reason for postponing cost-effective
measures to prevent environmental
degradation.”
Ratified as part of the Rio Declaration from the 1992 United Nations
Conference on Environment and Development.
There does not have to be visible oiling for
oil to have adverse impacts.
Direct Impacts without visible oiling
•Narcosis
•Organ failure
•Other physiological impairments
Indirect impacts without visible oiling
•Starvation due to loss of prey species
•Immune impairment
The Marine Food Web in the Northern Seas is Particularly
Susceptible to Disruption at the Primary to Secondary
Productivity Level leading to the Forage Fish Complex
What Hydrocarbons in Crude Oil are Toxic ?
Characteristic
or
Component
Crude Oil
Prudhoe
Bay
South
Louisiana
Kuwait
API Gravity
27.8
34.5
31.4
Naphtha Fraction (%)
bp = 20–205 oC
23.2
18.6
22.7
Paraffins
Naphthenes
Aromatics
High-boiling Fraction (%)
bp >205oC
12.5
7.4
3.2
8.8
7.7
2.1
16.2
4.1
2.4
76.8
81.4
77.3
Saturates
Aromatics
Benzenes
Naphthalenes
3-ring PAH
Thiophenes
4-ring PAH
14,4
25.0
7.0
9.9
4.6
3.0
--
56.3
16.5
3.9
1.3
3.7
0.9
--
34.0
21.9
4.8
0,7
1.8
9.3
0.2
Polar Materials (%)
ASTM D-2007
2.9
0.4
17.9
1.2
0.2
3.5
Insolubles (%)
ASTM D-893
Abstracted from NRC, 1985
Toxicity
Mostly acute narcosis;
possibly lethal
Acute narcosis & cancer
Cardiac edema & skeletal
malformation (BSD)
Cancer
Mostly unknown; possibly
very serious; ????????
Weathering of Alaska North Slope Oil PAH Fraction
Fresh
BSD & Related Pathologies
Cancer
Seven Years
Natural
Weathering
Factors Determining Toxicity
of
Compound & Mixtures
•Structure of the Compound(s)
•Species & Life Stages Exposed
•Route of Exposure
•Dose & Duration of Exposure
•Uptake & Bioaccumulation
•Metabolism & Removal of Toxic Substances
Environmental
Exposure
Bioaccumulation
Metabolism
Adverse Effects
Adverse effects of crude oil in the environment may be
amplified by bioaccumulation either within individuals, or
up the food chain. Many PAH require metabolic
transformation to either their toxic form, or to detoxify
them prior to removal from the body.
Dose Response & Chemical Specificity for
On-set of “Blue Sac Disease”
(a) Short and Springman, 2007
(b) Incardona, 2007
Bottlenose Dolphin Unusual Mortality Event (UME)
Northern Gulf of Mexico (2010-2014).
Summary of strandings
Cetaceans Stranded
Phase of Oil Spill
Response
Dates
114 cetaceans
stranded
prior to the response February 1, 2010phase for the oil spill April 29, 2010
122 cetaceans
stranded or were
reported dead
offshore
during the initial
April 30, 2010response phase to the November 2, 2010
oil spill
901 cetaceans strand after the initial
November 3, 2010 ed*
response phase ended March 16, 2014**
Bottlenose Dolphin
Unusual Mortality Event (UME) in
Northern Gulf of Mexico (20102014).
BP/Deepwater Horizon
NRDA Cummulative Oiling
NOAA ERMA website
Northern GOM UME
All Species
All Years
NOAA OPR Website
Actual Strandings / Average non-UME Strandings
Normalized Strandings Data for UME
February 2010-January 2014
8
7
6
5
4
3
2
1
All Bn Dolphins
<115 cm Bn Dolphins
Poly. (All Bn Dolphins)
Calendar Quarters have been shifted one month so Q2:10 begins May 01, 2010
Proportion of dolphins categorized as having normal (green),
mild (yellow-green), moderate (yellow), and severe (red) (A)
alveoloar interstitial syndrome and (B) overall lung disease.
Numbers inside bars represent number of cases in each
category.
Schwacke, L.H., et al (2013) Health of Common Bottlenose Dolphins (Tursiops
truncatus) in Barataria Bay, Louisiana, Following the Deepwater Horizon Oil Spill.
Environ. Sci. Technol.
How do Chemical Dispersants Work as Oil
Spill Response Counter Measures?
•Application of chemical
dispersants does not remove any oil
from the environment.
• Neither does the dispersant per se
cause degradation of any oil.
• Dispersant applications in major
oil spills have never prevented all
oil from reaching the shorezone.
• Dispersants facilitate the action of
wave energy in temporarily
suspending small oil droplets in the
water column.
Effectiveness of Dispersants &
Toxicity of Dispersed Hydrocarbons
Dilution
Degradation
Most adverse environmental effects resulting from use of
chemical dispersants are caused by increasing the
concentration and bioavailability of toxic hydrocarbons in
proximity to sensitive species. These impacts may be
partially mitigated by prompt dilution and degradation.
Susceptibility of Petroleum Hydrocarbons to
Biodegradation
from Most Susceptible to Least
Class of Hydrocarbon
n-Alkanes
Branched alkanes
Susceptibility to Biodegradation
C3 ~ C8-C12 > C6-C8 ~ C12-C15 > C16 ~ C25+
Monomethyl > Polymethyl > Highly
branched
Benzene & Alkyl-benzenes Benzene > Toluene > Ethylbenzene ~
Xylene
PAH
1-ring > 2-rings > 3-rings > 4-rings
Alkyl-PAH
Methyl & Dimethyl > Trimethyl or
extended alkylated species
Modified from Prince and Walters, 2007.
Effectiveness of Dispersants &
Toxicity of Dispersed Hydrocarbons
Summary of recent findings:
1. The chronic toxicity of aromatic hydrocarbons in crude
oil is largely due to 3- to 4- ringed alkyl-substituted
polycyclic aromatic hydrocarbons (PAH).
2. Use of chemical dispersants increases the concentration
of PAH in the seawater phase approximately 100 fold.
3. Three to 4-ringed PAH are less likely to remain within
dispersants-containing droplets than are smaller
aromatic hydrocarbons.
Effectiveness of Dispersants &
Toxicity of Dispersed Hydrocarbons
Summary of recent findings (Slide 2):
4. The depth of the mixing layer is more important than
total water depth in estimating dilution.
5. Short term exposures of <24 hr will cause longer term
chronic impacts.
6. Concentrations of <300 ppb have been shown to have
the following adverse impacts on one or more of the
fish species studied: 1. abnormal embryo development,
2. abnormal cardio-skeletal development of fry, 3.
decreased burst swimming speed in exposed adults
Not all the tools always belong
in every tool box
Discussion