E X E C U T I V E S U M M A RY
WATER ENVIRONMENT RESEARCH FOUNDATION
WA S T E WATER TREATMENT AND REUSE
Technical Brief: Trace Organic Compounds
and Implications for Wastewater Treatment
I
n 2005, WERF published the Technical Brief
on Endocrine Disrupting Compounds and
Implications for Wastewater Treatment
(stock no. 04WEM6). The brief summarized
pertinent information in the scientific literature
on endocrine disrupting compounds (EDCs),
sometimes known as pharmaceutically or
h o rmonally active agents or endocrine
m o d u l a t o rs. It was prepared in response to
concerns over the potential for EDCs to enter
the environment in treated wastewater
discharges and land application of biosolids
generated during wa s t ewater treatment.
B E N EFITS
 Evaluates the potential human health
and ecological effects of TOrC that may be
discharged to surface wa t e rsand/or taken
up in public water supplies.
 Provides information on identifying and
measuring the levels of TOrC and
describes the removal processes in typical
wastewater treatment.
 Identifies management strategies being
considered or implemented.
The ability to detect and measure trace org a n-
Since 2005, an increasing body of data
ics in the environment is a critical link to underdocuments the discharge and occurrence of
standing their sources, potential effects, and
trace organic compounds (TOrC), including
removal options.
EDCs in aquatic environments. Lack of
methods and assessment tools to integrate and interpret available data presents a
challenge for water quality managers to determine the significance of TOrC in local
systems. Providing essential technical tools and information regarding TOrC remains a top
research priority for WERF.
This technical brief builds on the 2005 document. It examines the state of knowledge on
TOrC and their implications for wa s t ewater treatment plants (WWTP) in the United States.
This brief rev i ews data on 720 TOrC and explores treatment, potential human and
ecological effects, and regulation of TOrC.
RELATED PRODUCTS
Removal of Endocrine Disrupting
Compounds in Water Reclamation Systems
(01HHE20T)
Innovative DNA Array Technology for
Detection of Pharmaceutics in Reclaimed
Water (01HHE21T)
Contributions of Household Chemicals to
Sewage and their Relevance to Municipal
Wastewater Systems and the Environment
(03CTS21UR)
Fate of Pharmaceuticals and Pe rsonal Care
Products through Wastewater Treatment
Processes (03CTS22UR)
Key Findings
Disinfection of Wastewater Effluent:
Pros and Cons of Technologies (04HHE4)
No definitive evidence of harm to human health
 To date, there is no definitive evidence of harm to human health from TOrC in WWTP
effluents. Howev e r, reported observations and initial research suggests watchful caution
but not alarm .
Technical Brief and Fact Sheet: Endocrine
Disrupting Chemicals and Implications for
Wastewater Treatment (04WEM6,
04WEM6a)
 Detection and measurement of trace organics in the environment remains challenging,
but is a critical link to understanding their sources, potential effects, and removal options.
Removal processes have variable success
 Typical WWTP processes reduce the concentrations of many TOrC.
Advanced treatment processes used for nutrient reduction can provide additional
r e m oval of TOrC.

The fate of each TOrC in a MWWTP depends on its physical and chemical characteristics
and on plant operation. Some TOrC can be removed almost entirely, while other TOrC
classes exhibit limited remov a l .

Determining effects to aquatic biota from TOrC in WWTP effluents is difficult
 The presence of trace levels of numerous TOrC as a mixture in WWTP effluent makes it
difficult to link ecological effects with a specific TOrC. Specific TOrC have been linked with
WERF Workshop on Trace Organics:
Mapping a Collaborative Researc h
Roadmap (06CEC1W)
RELATED ONGOING RESEARCH
Evaluating Trace Organics' Impact on
Aquatic Populations and Communities
(CEC5R08)
Trace Organic Compounds Removal during
Wastewater Treatment (CEC4R08)
AVAILABLE FORMAT
Soft cover and online PDF.
E X E C U T I V E S U M M A RY
Technical Brief: Trace Organic Compounds (TOrC) and Implications for Wastewater Treatment
Trace Organic Compounds (TOrC) are defined as
compounds that are known or suspected to be released
to the aquatic environment but are not commonly regulated
or monitored, and whose potential risk to human or
ecological health are relatively unknown.
specific effects in experimental settings but at higher concentrations than found in typical
WWTP effluent.
 Biological changes associated with classes of TOrC (e.g. , compounds with estrogenic
potential) have also been observed downstream of some WWTPs, although the extent and
biological significance of these changes remains unclear.
 Evaluating potential effects on ecological receptors are more complex than assessing
potential human health effects because many different kinds of organisms may be
affected. Researchers need to consider interactions (e.g., predator-prey links), and various
functions within an ecological system.
More regulatory involvement expected
 U.S. EPA analytical methods used for environmental characterization and regulatory
p u rposes have focused on commonly used industrial chemicals. Generally, these methods
cannot satisfy measurement needs for the expanded universe of trace organics, requiring
n ew analytical methods to be developed and approved.
 R e g u l a t o rs are beginning to implement source reduction measures for the management
of TOrC. Expect lobbying pressure for stronger regulations to reduce potential TOrC
releases into receiving waterbodies.
F u t u re Research Needs
The research team identified that the first and most pressing need moving forward is to
prioritize the TOrC we need information about and the data gaps.
CONTRACTOR
Paul Anderson, Ph.D.
AMEC Earth and Environmental, Inc.
PROJECT TEAM
Kimberly Groff, Ph.D.
Marilyn Hoyt
Barbara Pugh
John Samuelian, Ph.D.
Kathleen Sellers , PE
AMEC Earth and Environmental, Inc.
TECHNICAL REVIEW COMMITTEE
Robert Arn o l d , Ph.D.
U n i v e rsity of Arizona
James Duncan, Ph.D.
CH2M HILL
Margaret Nellor
Nellor Environmental Associates
Amy Woodis
Metro Water Reclamation District, Colorado
Elizabeth Toot-Levy
Northeast Ohio Regional Sewer District
Drew McAvoy
Procter and Gamble
WERF’s research challenge on Trace Organics will begin the task of prioritizing TOrC based
on the potential to impact aquatic populations and communities as part of its research
activities.
A detailed analyses, as well as an interactive listing of ongoing research, references, and
sources for additional information is included in this report.
TO ORDER
Contact WERF at 703-684-2470 or visit
www.werf.org and click on Publications.
WERF Subscribers :
Your first copy of this report is free.
Additional copies are $10 each or download unlimited free PDFs at www.werf.org.
Non-Subscribers:
Hardcopy: $175 PDF: $50
Refer to: STOCK
NO. CEC3R07
For more information, log on to
www.werf.org.
01/09
Water Environment Research Foundation

635 Slaters Lane, Suite 300 Alexandria

VA 22314-1177