PCB TMDL Handbook
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Structure of Poly chlorinated Biphenyt (PCB) Molecule
U.S. Environmental Protection Agency
Office of Wetlands, Oceans and Watersheds
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DISCLAIMER
This document provides technical guidance and recommendations to states, authorized
tribes, and other authorized jurisdictions to develop Total Maximum Daily Loads
(TMDLs) for legacy pollutants like polychlorinated biphenyls (PCBs) under the Clean
Water Act (CWA). Under the CWA, states, authorized tribes and US Environmental
Protection Agency (USEPA) establish TMDLs to implement water quality standards in
impaired waterbodies. State and tribal decision-makers retain the discretion to adopt
approaches on a case-by-case basis that differ from this guidance when appropriate
and scientifically defensible. While this document contains USEPA's recommendations
and guidance, it does not substitute for the CWA or USEPA regulations; nor is it a
regulation itself. Thus it cannot impose legally binding requirements on USEPA, states,
authorized tribes, or the regulated community, and it might not apply to a particular
situation or circumstance. USEPA may change this guidance in the future.
December 2011
EPA 841 -R-11-006
U.S. Environmental Protection Agency
Office of Wetlands, Oceans and Watersheds
Watershed Branch (4503T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
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Polychlorinated Biphenyl (PCB) Total Maximum Daily Load (TMDL) Handbook
Contents
Cover Letter
I. Overview 1
A. What is the purpose of this handbook?
B. Which pollutant are we addressing?
C. What are PCBs?
II. Factors to Consider in Early Stages of PCB TMDL Development 2
III. Identification of Waterbodies, Pollutant Sources, Priority Ranking 4
IV. Water Quality Standards and TMDL Target 5
V. Loading Capacity - Linking Water Quality and Pollutant Sources 9
VI. Linking Water Quality and Pollutant Sources - Point Source Loadings 9
VII. Linking Water Quality and Pollutant Sources - Nonpoint Source Loadings...10
VIII. Wasteload Allocation (WLA) 13
IX. Load Allocation (LA) 16
X. Margin of Safety (MOS) 16
XI. Critical Conditions and Seasonal Variation 18
XII. Reasonable Assurance 18
XIII. Post-TMDL Monitoring 19
XIV. Implementation 20
Appendix: PCB Sources
Table 1. Databases for PCB Sources Appendix page 1 of 2
Table 2. General PCB Sources Appendix page 2 of 2
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF WATER
December 20, 2011
MEMORANDUM
SUBJECT: Polychlorinated Biphenyl (PCB) Total Maximum Daily Load (TMDL)
Handbook
FROM: Tom Wall, Acting DirectorIsl
Assessment and Watershed Protection Division
TO: Water Division Directors, Regions 1-10
I am pleased to provide the attached document entitled "PCB TMDL Handbook." The
purpose of the attached handbook is to provide Regions, states, and other stakeholders
with a compendium of updated information for use in developing total maximum daily
loads (TMDLs) for waterbodies impaired by polychlorinated biphenyls (PCBs). This
handbook identifies various approaches to developing PCB TMDLs and provides
examples of them from around the country, complete with Web references.
PCBs rank sixth among the national causes of water quality impairment in the country.
Of the 71,000 waterbody-pollutant combinations listed nationally, over 5,000 (eight
percent) are PCB-related. However, of the more than 46,000 TMDLs in place
nationally, only about 400 (less than one percent) address PCBs as a pollutant. Our
intent is that this handbook will aid in the completion of PCB TMDLs, particularly where
these TMDLs will address ongoing and significant sources of PCBs.
The handbook opens with background on what PCBs are and some factors to consider
in the early stages of TMDL development (e.g., scale, modeling approaches). Next, the
handbook identifies the key elements of a TMDL (e.g., "Identification of Waterbodies,
Pollutant Sources, Priority Ranking," "Water Quality Standards and TMDL Target,"
"Wasteload Allocation") and discusses how those elements can be addressed in PCB
TMDLs. The handbook also summarizes and provides Web resources for related tools,
including databases for PCB sources, references for analytical methods, and regional
air monitoring initiatives.
We thank those who provided assistance in the development of this information and
provided comments, including States. If you have further questions, please do not
hesitate to contact me at 202-564-4179, or have your staff contact Sarah Furtak at 202-
566-1167.
Attachment
cc: Alexandra Dunn, ACWA
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Polychlorinated Biphenyl (PCB) Total Maximum Daily Load (TMDL) Handbook
I. Overview
A. What is the purpose of this handbook?
In this handbook, we aim to provide stakeholders with a compendium of updated
information for using total maximum daily loads (TMDLs) to address waterbodies
impaired by polychlorinated biphenyls (PCBs) consistent with Clean Water Act
(CWA) section 303(d) and EPA regulations at 40 CFR §130.7(c)(1).
This handbook will identify different approaches that have been successfully used to
develop PCB TMDLs and provide examples. In particular, the handbook will
address how to develop PCB TMDLs that account for all sources of PCB
contamination (including "passive" sources such as landfills in which PCBs are
contaminating the soil). One goal of this handbook is to illustrate how development
of PCB TMDLs take into account other program considerations (e.g., Water Quality
Standards [WQS]), and how TMDLs may benefit from tools available in other
programs (e.g., Superfund).
B. Which pollutant are we addressing?
The focus of this handbook is on PCBs, one of the most significant legacy pollutants
in terms of number of waterbodies impaired. PCBs rank sixth atop national causes
of impairment as tracked in the Assessment, TMDL Tracking, and Implementation
System (ATTAINS). PCBs represent about eight percent of all causes of impairment
nationally on CWA section 303(d) lists.1
C. What are PCBs2?
PCBs are a family of chlorinated organic compounds formed by two benzene rings
linked by a single carbon-carbon bond. Various degrees of substitution of chlorine
atoms for hydrogen are possible on the remaining ten benzene carbons. There are
209 possible arrangements of chlorine atoms on the biphenyl group. Each individual
arrangement or compound is called a congener. Thirteen of the 209 congeners are
known to show toxic responses similar to those caused by 2,3,7,8
tetrachlorodibenzo-p-dioxin (TCDD), the most toxic dioxin compound.
Historically, PCBs were produced in very large quantities both within and outside the
United States. Although their uses in capacitors and transformers are well known,
PCBs were also used in a wide variety of applications including some involving
direct contact with the environment (e.g., building materials, paints, sealants). In the
United States, commercial PCBs production started in 1929 and continued until
This estimate is based on current cause of impairment listings in the ATTAINS database
(http://iaspub.epa.gov/waters10/attains nation cv.control?p report type=D November 18, 2011; this estimate is based on the
most recent CWA section 303(d) and 305(b) data reported to EPA by states and available in ATTAINS.
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/proqrams/TMDLs/sfbavpcbs/Staff Report.pdf.
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1977. Importation of PCBs continued after U.S. production was banned until
January 1, 1979.
PCB congeners vary markedly in their chemical and physical properties depending
on the degree and position of chlorination. Important properties such as non-
flammability, low electrical conductivity, high thermal stability, and high boiling point
make PCBs highly stable and persistent in the environment. PCBs are also soluble
in non-polar organic solvents and biological lipids, hence their tendency to
bioaccumulate in living organisms.
II. Factors to Consider in Early Stages of PCB TMDL Development
With respect to development and establishment of PCB TMDLs, as with TMDLs
addressing other pollutants, a variety of factors will determine the appropriate
"investment" of time and resources. Motivating factors for prioritizing establishment of
PCB TMDLs include the following:
• Consent decrees - Legal obligation may drive the establishment of these
TMDLs.
• Stakeholder interest - National or local environmental or citizen's groups may
have a specific interest in particular legacy pollutant listings or TMDL
development decisions.
• Risk to human health and the environment - PCB "hot spots" in urban areas
(e.g., a Superfund site) may be viewed as high priority for remediation or TMDL
development to reduce risks to humans. When developing PCB TMDLs,
consider developing targets protective for both human health and wildlife.
Other factors determining "investment" of time and resources with respect to PCB
TMDLs, as with TMDLs addressing other pollutants, may include the scale at which
PCB TMDLs are developed, pollutant sources, and the modeling approaches available:
• Scale -- PCB sources tend to vary in combinations and concentrations from
waterbody to waterbody, and hotspots may exist. States should be careful to
think about PCB concentrations when selecting the scale at which a PCB TMDL
is written. For example, the Delaware River Estuary is a large-scale
multijurisdictional waterbody spanning the States of DE, PA, and NJ. A TMDL
was established for each of five riverine zones in order to account for the
variations in PCB concentrations throughout the estuary.3 The Delaware River
Estuary PCB TMDLs are being revised at the time of this handbook's
development.
Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, December 15, 2003,
available at http://www.epa.gov/reg3wapd/tmdl/pa tmdl/DelawareRiver/TMDLreport.pdf.
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PCB TMDL Handbook
Sources - A PCB TMDL can more quickly guide cleanup if a localized source or
sources are determined to be affecting the waterbody (e.g., Superfund site,
illegal discharge), and in turn, remediation tools and/or legal authorities are
available to control the source(s). On the other hand, if the sources are more
diffuse or not amenable to existing controls, environmental outcomes or benefits
may manifest more slowly.
Appendix Tables 1 and 2 identify common PCB sources (e.g., incinerators,
wastewater treatment plants) and related databases.
Modeling approaches -- Various modeling approaches are available for
developing PCB TMDLs. Level one, level two, and level three techniques for
TMDL development are briefly contrasted below:
o Level one approaches for PCB TMDLs include non-modeling
approaches, such as assuming a proportional one-to-one relationship
between PCB loadings and fish tissue, and using a bioconcentration factor
to calculate a water column value. A level one approach may also involve
back-calculating from the sediment targets and sediment data to
determine the loading capacity. Examples of TMDLs that have used a
level one approach include the Kawkawlin River in Michigan4, Lower
Okanogan River Basin in Washington5, and TMDLs in California (San
Diego Creek and Newport Bay6, and Calleguas Creek7).
o Level two approaches may involve mass balance modeling, which
estimate PCB concentrations in the water column, fish tissue and
sediment using sampling data. An example of an intermediate modeling
approach is the Shenandoah PCB TMDL8
o Level three approaches may involve linking a hydrodynamic sediment
transport model with a PCB fate and transport model, and may also be
linked with a watershed model. Examples of such complex models
applicable to PCBs include a modified WASP-DYNHD hydrodynamic
4
Total Maximum Daily Load for Polychlorinated Biphenyls for the Kawkawlin River, Bay County, Michigan, August 2002, available
at http://www.epa.gov/waters/tmdldocs/3843 tmdl-kawkawlin.pdf.
Lower Okanogan River Basin DDT and PCBs Total Maximum Daily Load, October 2004, available at
http://www.ecv.wa.gov/pubs/0410043.pdf.
Total Maximum Daily Loads For Toxic Pollutants San Diego Creek and Newport Bay, California, June 14, 2002, available at
http://www.waterboards.ca.gov/santaana/water issues/programs/tmdl/docs/sd crk nb toxics tmdl/summarv0602.pdf.
Calleguas Creek Watershed OC Pesticides and PCBs TMDL Technical Report, June 20, 2005, available at
http://www.waterboards.ca.gov/losangeles/board decisions/basin plan amendments/technical documents/2005-
010/05 0426/OC 6 TechnicalReport.pdf.
"Shenandoah River PCB TMDL," available at http://www.epa.gov/reg3wapd/tmdl/VA TMDLs/Shenandoah/index.htm.
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PCB TMDL Handbook
model (used in the Delaware River Estuary PCB TMDLs9 and the Tidal
Portions of the Potomac and Anacostia Rivers TMDLs10).
III. Identification of Waterbodies, Pollutant Sources, Priority Ranking
As described in existing EPA guidance, TMDLs, including PCB TMDLs, should include
the following11:
• Identification of specific waterbody and pollutant (PCBs) addressed by the TMDL.
• Identification of the pollutant sources, including quantity and location(s) of
National Pollutant Discharge Elimination System (NPDES)-permitted sources
within the waterbody (including regulated stormwater sources) and nonpoint
sources (including non-regulated stormwater sources) (also see section VI of this
handbook identifying point source loadings).
• Source assessment, including amount of PCBs from air deposition, and
contribution from point and legacy sources (e.g., sediments; also see section VII
on nonpoint source loadings). Although a comprehensive source assessment
can be challenging, states are encouraged to consider the best available data in
identifying PCB sources, and to describe how PCB sources were identified.
Commensurate with historic data and information on PCB presence, budget, and
other priorities, conducting a good source assessment as part of a TMDL can
help ensure that all sources are accounted for, and in turn, ensure that the TMDL
can be better designed to address those sources. Method 1668C: Chlorinated
Biphenyl Congeners in Water, Soil, Sediment, Biosolids, and Tissue by
HRGC/HRMS guidance describes the PCB analysis method the EPA developed
for use in CWA programs and for wastewater, surface water, soil, sediment,
biosolids, and tissue matrices.12
• Linkage to 303(d) list/Integrated Report (i.e., identify waterbody and impairment
as it appears on the 303(d) list, the listing cycle, and priority ranking of the
waterbody).
• Identification of other factors within the waterbody or watershed that may affect
PCB loadings (e.g., watershed area, land use/land cover, population, future
growth, distribution of sources and loadings, including air deposition, etc.).
9
Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, December 15, 2003,
available at http://www.epa.gov/reg3wapd/tmdl/pa tmdl/DelawareRiver/TMDLreport.pdf. Note that these TMDLs are being revised
at the time of this handbook's development.
Total Maximum Daily Loads of Polychlorinated Biphenyls (PCBs) for Tidal Portions of the Potomac and Anacostia Rivers in the
District of Columbia, Maryland, and Virginia, October 31, 2007, available at
http://www.potomacriver.org/cms/index.php?option=com content&view=article&id=136:tidal-pcb-tmdl&catid=41:pollution<emid=1.
Unless otherwise noted, "existing guidance" in this handbook refers primarily to EPA's guidance for TMDL approvals, Guidelines
for Reviewing TMDLs under Existing Regulations issued in 1992, available at
http://www.epa.gov/owow/tmdl/auidance/final52002.pdf. Although some information is repeated from the 1992 guidance, this
handbook does not replace that guidance.
Method 1668C: Chlorinated Biphenyl Congeners in Water, Soil, Sediment, Biosolids, and Tissue by HRGC/HRMS guidance,
April 2010, is available at http://water.epa.gov/scitech/methods/cwa/other.cfm. The EPA proposed this method in a September 23,
2010 Federal Register notice and is currently reviewing comments on the proposed rule. A decision has not been made on the
promulgation of this method. Additional background on PCB analysis includes: Muir, Derek and Ed Sverko, 2006. Analytical
methods for PCBs and organochlorine pesticides in environmental monitoring and surveillance: a critical appraisal. Anal Bioanal
Chem. 386: 769-789, available at
http://www.inweh.unu.edu/Coastal/CCPP/2009 Merida/Reports/Muir&Sverko AnalBioanalChem2006.pdf.
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Maryland and Virginia have recently published a source tracking study and point source
guidance, respectively, that may be informative to other states. The "2005 Caged
Clam Study to Characterize PCB Bioavailability in the Impaired Watersheds throughout
the State of Maryland" aimed to characterize Maryland subwatersheds draining into the
PCB-impaired tidal waters as (i) those with no apparent sources and (ii) those with
relatively significant sources of PCB runoff.13 Virginia Department of Environmental
Quality personnel refer to a "Guidance for Monitoring of Point Sources for TMDL
Development Using Low-Level PCB Method 1668" when selecting the types of facilities
that should be targeted for PCB monitoring (within PCB fish impaired waterbodies) and
for its standard operating procedures for sample collection, Method 1668 analysis of the
samples, and submittal of PCB data to VADEQ by permitted dischargers.14
Pursuant to CWA section 308, the EPA may enter and inspect the facilities and records
of current NPDES permit holders. Inspections ascertain the degree of compliance with
requirements of the NPDES permit. During such an inspection, representatives may
observe process operations, inspect monitoring equipment and lab methods, collect
samples, and examine appropriate records.15 The opportunity to observe or collect
samples may help identify point sources of PCBs that otherwise would have escaped
detection.
IV. Water Quality Standards and TMDL Target
TMDLs are established at a level that attains and maintains the applicable WQS,
including designated uses, numeric and narrative criteria, and antidegradation policy [40
CFR§130.7(c)(1)]:
• Depending on the impairment being addressed by the TMDL, existing criteria
may include human health, aquatic life, and wildlife criteria.
• The state's existing numeric PCB criterion may be a water column concentration
or fish tissue value.
• TMDLs identify a numeric TMDL target or WQS criterion, a quantitative value
used to attain and maintain applicable WQS, including designated uses. A
TMDL also includes, as necessary depending on the nature of the sources, load
allocations (LAs) and wasteload allocations (WLAs) [40 CFR § 130.2(i)].
Where a fish tissue target is used for the TMDL, appropriate justification for using a fish
tissue target should be included, considering existing numeric and narrative criteria as
well as designated uses.16 For example, where a state has a narrative criterion such as
13
Available at http://www.mde.state.md.us/assets/document/2005 Corbicula Study final.pdf.
14
Guidance for Monitoring of Point Sources for TMDL Development Using Low-Level PCB Method 1668, March 6, 2009, available
at http://www.dect.Virginia.gov/watemuidance/pdf/09200l.pdf. Additional background on PCB analysis includes: Muir, Derek and
Ed Sverko, 2006. Analytical methods for PCBs and organochlorine pesticides in environmental monitoring and surveillance: a
critical appraisal. Anal Bioanal Chem. 386: 769-789, available at
http://www.inweh.unu.edu/Coastal/CCPP/2009 Merida/Reports/Muir&Sverko AnalBioanalChem2006.pdf.
NPDES Compliance Inspection Manual- Appendix E: Sample Section 308 Letter, available at
http://www.epa.aov/oecaerth/resources/publications/monitoring/cwa/inspections/npdesinspect/npdesinspect.pdf.
As described in the Guidance for 2006 Assessment, Listing and Reporting Requirements Pursuant to Sections 303(d), 305(b)
and 314 of the Clean Water Act ("2006 IR Guidance"), when deciding whether to identify a segment as impaired, states should
determine whether there are impairments of designated uses and narrative criteria, as well as the numeric criteria. The guidance
notes that, while numeric human health criteria for ambient water column concentrations of pollutants are a basis for determining
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"no toxics in toxic amounts," and where a state considers there to be an impairment of a
designated use due to presence of a fish consumption advisory, it may be appropriate
to use a fish tissue target to interpret a narrative standard. Reliance on advisories may
decrease as PCB detection levels become more precise/sensitive. The TMDL should
include a demonstration of how meeting the fish tissue target will achieve WQS [40 CFR
§130.7(c)].
In the San Francisco Bay PCB TMDL, the numeric target is a fish tissue concentration
as fish tissue PCB concentrations are the direct cause of impairment of the designated
uses. In the Palouse River Chlorinated Pesticide and PCB TMDL, numeric targets are
based on fish tissue; the determination as to whether WQS have been achieved is
based on fish tissue criteria.17
Multi-state scale
For a TMDL established for a multi-jurisdictional waterbody, in addition to the above
elements, TMDLs identify WQS for each applicable state and established at a level to
attain and maintain the WQS in each state. The TMDL should demonstrate that it is set
at a level to achieve the WQS in each state; where the state standards are different,
the TMDL should include a separate TMDL calculation to meet each standard.
Large, multi-state PCB TMDL examples include the Delaware River Estuary, Ohio
River, and the Potomac River and Anacostia River TMDLs. The Delaware River
Estuary TMDL - being revised at the time of this guidance - addresses impairments
listed in DE, NJ, and PA. The Ohio River TMDL considered WV, OH, and PA WQS;
the WV standard, being most protective of human health, was used to establish TMDL
endpoints within the TMDL segment. The Potomac River and Anacostia River TMDLs
address impairments listed in DC, MD, and VA and are written with allocations to
achieve water column concentrations less than or equal to jurisdiction-specific water
quality criteria and water column and sediment concentrations less than or equal to
jurisdictional fish tissue thresholds.
Total PCBs
For San Francisco Bay in California, the EPA established the PCBs water quality
criterion for the protection of aquatic life based on the sum of Aroclors (i.e., the trade
name given to different types of PCB mixtures) and for the protection of human health
based on total PCBs (e.g., the sum of all congeners, or isomers or homologs or Aroclor
analyses).18
impairment, the attainment of such criteria does not always mean that designated uses are being protected. For example, a
segment can be meeting numeric ambient water quality criteria, but not attaining the designated uses because fish or shellfish
tissue concentrations exceed levels that are protective of human health or levels used as the basis for fish consumption advisories.
See the 2006 IR Guidance for additional information on listing waters with fish or shellfish consumption advisories at
http://www.epa.aov/owow/tmdl/2006IRG.
Palouse River Chlorinated Pesticide and PCB Total Maximum Daily Load Water Quality Improvement Report and Implementation
Plan, July 2007, available at http://www.ecv.wa.gov/pubs/0703018.pdf.
18
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbaypcbs/Staff Report.pdf and
"Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California. 40 CFR Part 131.38."
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In San Francisco Bay and Calleguas Creek PCB TMDLs19, the pollutant 'total RGBs',
has been defined as:
• Sum of Aroclors;
• Sum of the individual congeners routinely quantified by the Regional Monitoring
Program (RMP) or a similar congener sum; or
• Sum of the National Oceanic and Atmospheric Administration (NOAA) 18
congeners converted to total Aroclors. A comparison of the sum of 18 NOAA
congeners converted to Aroclor with quantified sums of Aroclors shows relatively
good correlation in one study20.
Sediment concentrations
Desorption of sediment-bound PCBs may contribute significantly to the concentrations
detected in water. PCBs, particularly the highly chlorinated congeners, adsorb strongly
to sediment and soil where they tend to persist with half-lives on the order of months to
years. Specific examples of PCB contamination in sediment follow:
Calleguas Creek21
The applicable water quality criteria for protection of aquatic life in the Calleguas
Creek Watershed are 0.014 ug/L [ppb] (freshwater) and 0.130 ug/L [ppb]
(marine). Multiple numeric targets (including fish, sediment, and water) are
considered in this TMDL as there is uncertainty that a single numeric target is
sufficient to ensure protection of designated beneficial uses. In order to address
impaired waters listings for PCBs in the water column, fish tissue, and sediment,
multiple targets are used to protect organisms, wildlife, and human health from
the potentially harmful effects of PCBs.
Sediment quality guidelines endorsed by NOAA and contained in NOAA's
Screening Quick Reference Tables are selected as numeric targets for PCB
sediment concentrations. Use of threshold effect level (TEL) values and effect
range low (EFL) values for marine sediment represents a conservative (i.e., more
protective) choice. Since these sediment guidelines are not EPA-approved
sediment quality criteria, they are used as numeric targets only for reaches with
sediment listings. The TMDL is calculated as a reduction in sediment
concentration, which is based upon fish tissue and water concentrations (and
consideration of sediment guidelines for reaches with sediment listings. In order
to translate required reductions in fish tissue and water column concentrations
into sediment concentration reductions, it is assumed that bioaccumulation
factors for fish tissue to sediment and partition coefficients for water to sediment
19
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbavpcbs/Staff Report.pdf.
Calleguas Creek Watershed OC Pesticides and PCBs TMDL Technical Report, June 20, 2005, available at
http://www.waterboards.ca.gov/losanaeles/board decisions/basin plan amendments/technical documents/2005-
010/05 0426/OC 6 TechnicalReport.pdf
NOAA. 1993. Sampling and Analytical Methods of the National Status and Trends Program-National Benthic Surveillance and
Mussel Watch Projects 1984-1992. NOAA Technical Memorandum NOS ORCA 71, Volume 1. July, 1993. pp.l-34-39.
21 Calleguas Creek Watershed OC Pesticides and PCBs TMDL Technical Report, June 20, 2005, available at
http://www.waterboards.ca.gov/losanaeles/board decisions/basin plan amendments/technical documents/2005-
010/05 0426/OC 6 TechnicalReport.pdf.
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are linear, and that a given percent reduction in fish tissue or water concentration
results in an equal percent reduction in sediment concentration.
Ohio River22
Although the operating WQS of 0.044 ng/L [0.000044 ug/L or ppb] for the water
column was used to establish TMDL endpoints, WV and OH conducted a
sediment survey to address water column PCB loads resulting in part from
resuspension of contaminated sediments and to identify "hot spots." Specific
sediment quality criteria for total PCBs have not been standardized for the Ohio
River; however, The Incidence and Severity of Sediment Contamination In
Surface Waters of the United States (EPA 823-R-97-006), also known as The
National Sediment Inventory, includes multiple PCB screening levels for the
protection of consumers. These values are based upon theoretic
bioaccumulation potential and cancer risk levels from the primary route of human
exposure to contaminated sediment: consumption offish. Screening levels are
guidelines for analysis of sediment quality data; they are not regulatory criteria.
San Francisco Bay23
The mass of PCBs in sediments is much greater than in the water column.
However, it is important to note that a numeric PCB criterion exists in California
for the water column but not for sediments.
PCB uptake by biota from sediment is well documented in the scientific literature.
In a shallow bay with a large sediment PCB reservoir, such as San Francisco
Bay, this is the most important pathway for PCB bioaccumulation in fish.
Therefore, reducing PCB concentrations in Bay sediments is the most effective
means of reducing fish tissue PCB concentrations. This TMDL uses a food web
model to translate the fish tissue numeric target to a corresponding sediment
concentration. It then uses a waterbody (mass budget) model to predict the long-
term fate of PCBs in the Bay and determine the external load of PCBs that will
attain the sediment concentration goal resulting in attainment of the fish tissue
numeric target.
Starting with the numeric fish tissue target of 10 ng/g [0.01 ug/g or 10 ppb], the
food web model yields a corresponding concentration of 1 ug/kg [0.001 ug/g, 1
ng/g, or 1 ppb] PCBs in sediment. This human consumption-based sediment
PCB concentration goal is much lower than the sediment concentration California
has deemed protective of wildlife of 160 ug/kg [0.160 ug/g, 160 ng/g, or 160 ppb]
total PCBs, and is therefore considered to result in attainment of all beneficial
uses currently impaired by PCBs.24
22 Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.aov/rea3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbavpcbs/Staff Report.pdf.
24 —
Water quality unit conversions available at US Geological Survey "Conversion Factors and Abbreviated Water-Quality Units,"
http://pubs.usas.gov/circ/circ1133/conversion-factors.html.
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V. Loading Capacity - Linking Water Quality and Pollutant Sources
TMDLs identify loading capacity and reductions needed to meet WQS [40 CFR
§130.2(f)].
As described in existing EPA guidance, TMDLs should provide documentation of the
approach used to establish a linkage between the numeric PCB target and PCB
sources, factors within the waterbody or watershed that may affect PCB loadings, the
strengths and weaknesses of the approach, and the results of any modeling. As
described earlier, however, factors such as likelihood of controlling the PCB source,
existence of consent decrees, and risk to human health and the environment will
influence level of investment devoted to modeling and analysis (see section II).
Examples of PCB fate-and-transport assumptions that may influence the calculations in
an approved TMDL include ocean influence treated as background and net burial of
PCBs into sediments that result in removal of PCBs from the system. Below are
additional considerations to bear in mind in conducting a linkage analysis:
• A linkage analysis may include water quality modeling or other analytical
approaches, although modeling is not required.
• Selecting an analytical approach depends on the type of questions to be
answered and may include simple, non-modeling approaches, mass balance
approaches, and more complex modeling approaches. Types of models that
may be used to calculate PCB TMDLs include steady-state, hydrodynamic, and
food web models. Results of air deposition modeling, as well as runoff models,
may also be used as input to water quality models in a linked approach (see
section II, "Factors to Consider...").
• Data on which the linkage analysis is based (e.g., waterbody characteristics,
sources, fish tissue data) should be included in the TMDL.
Where a fish tissue target is used to establish a TMDL, states are encouraged to
include the following items as part of the linkage analysis documentation. Unless
otherwise noted, examples of each item below can be found in the San Francisco Bay
PCB TMDL:
• A description of the fish tissue data (number of samples, concentration, locations,
etc.)
• Identification of the specific fish species, or multiple species, and
• Identification of statistic used to calculate the baseline PCB concentration and
the TMDL target (e.g., which percentile), and the rationale for the target level and
fish species used.
VI. Linking Water Quality and Pollutant Sources - Point Source Loadings
As described in existing TMDL guidance, the TMDL should, to the extent data allow,
identify specific point sources covered by the TMDL, and the total point source loadings.
Point sources may include wastewater treatment plants, combined sewer overflows
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(CSOs), municipal separate storm sewer systems (MS4), rail yards, landfills, or other
locations where capacitors, transformers, or other PCB-laden products have been used.
The EPA encourages states to consider the following in determining the total point
source loading of PCBs:
• States are encouraged to use data on point source loadings most representative
of current conditions where relevant information is available.
• Where facility or category-specific PCB discharge data are available and of
appropriate quality, states are encouraged to consider such data, and develop
estimates of PCB loadings applicable to each category of sources (e.g.,
wastewater treatment, power plants, stormwater, and other potential PCB
dischargers), rather than calculating a single average for all types of dischargers.
• Where source-specific data are not available, states are encouraged to develop
representative estimates for loadings for each source category or land use.
• States should indicate how they have accounted for PCB contributions from
NPDES-permitted stormwater sources in the estimate of total PCB loadings.
Contributions from NPDES-permitted sources should be included in the point
source estimate, and contributions from non-NPDES permitted stormwater
sources may be included in the estimate of nonpoint source loadings25. States
are encouraged to estimate contributions from specific NPDES-permitted
sources such as MS4s.
• Maps showing location of key sources, land-use, and other waterbody
characteristics are encouraged.
VII. Linking Water Quality and Pollutant Sources - Nonpoint Source Loadings
EPA regulations say that LAs "may range from reasonably accurate estimates to gross
allotments, depending on the availability of data and appropriate techniques for
predicting the loading" [40 CFR §130.2(g)]. The EPA encourages states to consider the
most recent and best available data.
As described in existing TMDL guidance, the TMDL should include estimates of
nonpoint source loadings (e.g., atmospheric deposition, contaminated sediment, runoff
from contaminated sites, groundwater). The EPA encourages states to consider the
following in developing such estimates:
• As with point sources, maps showing the location of key sources or source areas
are encouraged.
• Loading estimates should account for air deposition and nonpoint sources other
than those nonpoint sources containing loadings from air deposition (e.g., runoff
from waste sites, legacy sources). States may wish to use runoff models to
estimate PCB loadings to the waterbody from the watershed.
• While not necessary for developing the load allocation (LA), parsing out the
contributions to the air deposition loading may be helpful in developing an
implementation plan. Parsing out contributions to the air deposition loading is
25 "Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit
Requirements Based on Those WLAs," November 22, 2002, available at http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf.
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contingent upon decisions regarding the appropriate level of analysis; if
contribution from air is small, environmental outcomes or benefits may not be
commensurate with the amount of effort spent on this analysis. For example, in
contrasting two water quality impairment scenarios - a rural Kansas scenario vs.
a downtown Chicago scenario - industry codes in the latter may be able to help
identify PCB release information.
• Studies have also shown that PCB flux from water to air is significant; according
to the San Francisco Bay TMDL, PCBs escape to the atmosphere from the Bay
at a greater rate than they are deposited from the atmosphere, resulting in a net
loss of PCBs.26 Similarly, a Lake Michigan Mass Balance Study publication
concluded from the concentration and distribution of PCB congeners collected
from vapor over water, over land, and dissolved in the water, that volatilization of
PCBs from contaminated waters is a major source of PCBs to the local
atmosphere.27
• Developing a detailed source identification plan may be especially important in a
highly populated urban area for protection of human health.
• Where possible, the TMDL should include estimates of the contributions from air
deposition to permitted stormwater sources and account for such loadings in the
point source load estimate, rather than the nonpoint source load estimate.
Contributions from nonpermitted stormwater sources may be included in the
nonpoint source loading estimate.28
Examples of PCB TMDLs that quantify nonpoint source loadings include State of
Washington PCB TMDLs. In the Lower Okanogan River Basin DDT and PCB TMDL
and the Palouse River Chlorinated Pesticide and PCB TMDL, sediment, runoff from
waste sites, and legacy sources are considered to be nonpoint sources of focus.29
30The Lower Okanogan River Basin DDT and PCB TMDL examines the relationship
between contamination offish tissue and bottom sediments.31 Also, the Palouse River
Chlorinated Pesticide and PCB TMDL evaluates total suspended solids levels from
nonpoint source drainages and legacy hazardous waste sites.32
As mentioned earlier in this section VII, the nonpoint source loading portion of the TMDL
may include, as appropriate, LAs for contaminated sites. The Delaware River Estuary
PCB TMDLs, for example, acknowledge that reducing NPDES permitted point source
discharges alone will not be sufficient to achieve estuary WQS. Runoff from
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbavpcbs/Staff Report.pdf.
Hornbuckle, K.C. et al, 1993. Over-Water and Over-Land Polychlorinated Biphenyls in Green Bay, Lake Michigan. Environ. Sci.
Technol. 27(1): 87-98, abstract available at http://www.epa.gov/alnpo/lmmb/results/pubs.html.
\ / i i i i i i i i
"Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit
Requirements Based on Those WLAs," November 22, 2002, available at http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf.
Lower Okanogan River Basin DDT and PCBs Total Maximum Daily Load, October 2004, available at
http://www.ecv.wa.gov/pubs/0410043.pdf.
Palouse River Chlorinated Pesticide and PCB Total Maximum Daily Load Water Quality Improvement Report and
Implementation Plan, July 2007, available at http://www.ecv.wa.gov/pubs/0703018.pdf.
Lower Okanogan River Basin DDT and PCBs Total Maximum Daily Load, October 2004, available at
http://www.ecv.wa.gov/pubs/0410043.pdf.
Palouse River Chlorinated Pesticide and PCB Total Maximum Daily Load Water Quality Improvement Report and Implementation
Plan, July 2007, available at http://www.ecv.wa.gov/pubs/0703018.pdf.
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contaminated sites is a significant source of PCBs: the combined load from these 49
sites in the Delaware watershed comprises about 57% of the loading from Zone 3, 38%
of the loading from Zone 4, and about 46% of the loading from Zone 5.33
Regional air monitoring initiatives
There may be air deposition data that can be used in TMDL development as a result of
various air monitoring efforts. Air monitoring efforts include the following:
Great Lakes
Since 1990, the EPA's Great Lakes National Program Office (GLNPO) has
utilized the Integrated Atmospheric Deposition Network (IADN)34, a joint project
with Canada, to determine atmospheric PCB loadings, look at trends in PCB
concentrations, and use data to measure progress. IADN consists of 15
monitoring sites around the Great Lakes, five of which are US sites.
IADN also works with an EPA transformer database covering the Great Lakes
States, New York, Pennsylvania and New Jersey. IADN data indicate no
correlation between transformers and concentrations of PCBs (i.e., transformers
are fairly closed systems); however, it is likely that data are missing (e.g., there
may be discrepancies as industries have been phased out of the database).
GLNPO still recommends phasing out transformers associated with PCBs as a
means of restoring water quality within the Great Lakes system.
Western Airborne Contaminants Assessment Project (WACAP)
This project was initiated to determine risk to ecosystems and food webs in eight
core national parks - in the western US and Alaska - from long-range transport
of airborne contaminants. From 2002 to 2007, analysis of the concentration and
biological effects of contaminants in air, snow, water, sediment, lichen, conifer
needles, and fish was conducted in the national parks. Partners include the
National Park Service, the EPA, US Geologic Survey, US Forest Service, Oregon
State University, and University of Washington.35
New Jersey Atmospheric Deposition Network (NJADN)
NJ Department of Environmental Protection and Rutgers University partnered to
measure concentrations of PCBs in air (gas phase), aerosol (particle phase), and
precipitation at ten NJ sites representing an array of land-use regimes at regular
intervals between 1997 and 2003. Based on the measured gas, particle, and
precipitation phase concentrations, NJADN researchers estimated the
atmospheric deposition flux, or flow, of total PCBs at the different sites.36
33
Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, December 15, 2003,
available at http://www.epa.gov/reg3wapd/tmdl/pa trndl/DelawareRiver/TMDLreport.pdf.
34 —
USEPA IADN website is available at http://www.epa.aov/alnpo/monitoring/air2/index.html.
National Park Service and USEPA "Western Airborne Contaminants Assessment Project" available at
http://www.nature.nps.gov/air/Studies/air toxics/wacap.cfm and http://www.epa.gov/nheerl/wacap/. respectively.
NJ Dept. of Environmental Protection "New Jersey Atmospheric Deposition Network" available at
http://www.state.ni.us/dep/dsr/niadn/ and Atmospheric Deposition: PCBs, PAHs, organochlorine pesticides, and Heavy Metals
available at http://www.ni.gov/dep/dsr/trends2005/pdfs/atmospheric-dep-pcbs.pdf.
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San Francisco Estuary Institutes' Regional Monitoring Program for Trace
Substances (RMP) and Watersheds Science Program
The RMP is made up of a group of representatives from wastewater treatment
plants, stormwater agencies, industrial dischargers, and the San Francisco Bay
Water Board. The RMP works to support the development of TMDLs and other
water quality attainment strategies for the San Francisco Bay.
The Watersheds Science Program provides Bay area environmental managers
with quality science information in the context of the whole system (watersheds,
the airshed, wetlands, and the Bay).37
Chesapeake Bay Atmospheric Deposition Network Nutrient-Toxics
Deposition Monitoring Program (CBAD-NT)
The CBAD-NT was conducted at urban and non-urban sites along the shoreline
of the Chesapeake Bay during 1995-1999. The primary objective of the CBAD-
NT study was to provide the best possible estimates of total, annual atmospheric
loadings of nitrogen-based nutrients and organic contaminants, including PCBs,
directly to the surface waters of the Chesapeake Bay, and to conduct a study of a
series of key processes for estimating reductions in deposition to the watershed
and delivered loads to the tidal bay.
VIM. Wasteload Allocation (WLA)
TMDLs include WLAs which identify the portion of the loading capacity allocated to
individual existing and future point sources [40 CFR §130.2(h), 40 CFR §130.2(i)].
Consistent with the 2006 decision by the D.C. Circuit Court of Appeals in Friends of the
Earth v. EPA, the EPA has recommended that TMDL allocations be expressed as a
daily load39. Because PCB levels in fish represent bioaccumulation over longer periods
of time, it may be appropriate to express allocations in PCB TMDLs as both an annual
and daily load. If appropriate, states may also express allocations using other
averaging periods, such as seasonal, in addition to a daily load.
Stormwater
NPDES-permitted stormwater discharges are included in a TMDL's WLA [40 CFR
§130.2(h)40].
Here are three examples of TMDLs that address stormwater within their WLA:
San Francisco Estuarine Institute, "Programs" website, available at http://www.sfei.ora/programs.
OQ v
Maryland Power Plant Research Program, "Chesapeake Bay Atmospheric Deposition Network Nutrient-Toxics Deposition
Monitoring Program" available at http://www.esm.versar.com/pprp/features/Atmosdep/regional sites/cbadsnt/cbadnt prog.html.
See Establishing TMDL "Daily" Loads in Light of the Decision by the US Court of Appeals for the DC Circuit in Friends of the
Earth, Inc. v. EPA, et al., No. 05-5015, (April 25, 2006) and Implications for NPDES Permits at
http://www.epa.gov/owow/tmdl/dailvloadsguidance.html. Note that, as described in the latter memo, the Court decision regarding
daily loads does not imply that NPDES permit limits must be expressed in daily terms.
See "Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES
Permit Requirements Based on Those WLAs," November 22, 2002, available at http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf.
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San Francisco Bay41
The TMDL identifies the two major sources of PCB loadings to the Bay as Delta
inflow from the Central Valley watershed and urban stormwater discharges.
Sediments from the Central Valley watershed carry a large mass of PCBs but are
lower in concentration than in-Bay sediments, potentially helping to reduce
current impacts of PCBs on the Bay by burying more contaminated sediments.
Implementation of the TMDL is thus focused on reducing sediment PCB
concentrations by controlling PCB sources in urban stormwater discharges.
A potential means to reduce urban stormwater discharge of PCB loads might be
to strategically intercept and route stormwater to municipal wastewater treatment
facilities. The TMDL designates a separate WLA for discharges associated with
urban stormwater treatment via municipal wastewater treatment facilities, since
such actions will result in increased PCBs loads from municipal wastewater
dischargers. The individual WLAs for municipal wastewater treatment works
dischargers reflect current performance levels.
The TMDL also includes WLAs for stormwater discharges for each county.
These WLAs apply to all NPDES permitted municipal stormwater discharges.
These WLAs implicitly include all current and future permitted discharges within
the geographic boundaries of municipalities and unincorporated areas within
each county. Examples of sources of PCBs in stormwater discharges include, but
are not limited to, California Department of Transportation (Caltrans) roadways
and non-roadway facilities, atmospheric deposition, public facilities, properties
proximate to stream banks, industrial facilities, and construction sites.
Delaware River Estuary42
In the 2003 Stage 1 PCB TMDL for the tidal Delaware River, point sources
include all municipal and industrial discharges subject to regulation by the
NPDES permit program, including CSOs and stormwater discharges. This Stage
1 TMDL explicitly assigns a portion of each of the different estuary zone WLAs to
storm water discharges.
In developing the Stage 1 TMDLs, the WLAs were calculated for traditional point
source discharges based upon effluent concentrations and the actual effluent
flows during a one-year model cycling period.
Calleguas Creek43
An aggregate concentration-based WLA was developed for MS4s. The
aggregate allocation will apply to all NPDES-regulated municipal stormwater
41
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbavpcbs/Staff Report.pdf.
42 —
Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, December 15, 2003,
available at http://www.epa.gov/reg3wapd/tmdl/pa tmdl/DelawareRiver/TMDLreport.pdf.
43
Calleguas Creek Watershed OC Pesticides and PCBs TMDL Technical Report, June 20, 2005, available at
http://www.waterboards.ca.gov/losanaeles/board decisions/basin plan amendments/technical documents/2005-
010/05 0426/OC 6 TechnicalReport.pdf.
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discharges in the watershed. Stormwater WLAs will be translated into the
NPDES permits as ambient receiving water PCB concentration limits measured
at instream discharge points for each subwatershed. They will be achieved
through the implementation of best management practices (BMPs) as outlined in
the implementation plan. Compliance will be determined through the
measurement of in-stream water quality, sediment, and fish tissue
measurements at the base of each subwatershed. To facilitate stormwater co-
permittees measuring compliance in all six subwatersheds, additional monitoring
stations will be needed in four of the subwatersheds mentioned within the TMDL.
Reserve capacity and WLA
A portion of a TMDL's loading capacity may be set aside as a "reserve" to allow for
future increases in pollutant loading. Use of a reserve may be relevant to PCB TMDLs
in particular, as there may be unexpected discharges of PCBs not identified in the initial
TMDL. The concept of reserving loading capacity for "future" sources of pollutants is
expressly included in the definitions of "wasteload" and "load" allocations [40 CFR §
130.2(g), 40 CFR § 130.2(h)]. Thus, a TMDL may assign a WLA or LA to a particular
source that is larger than its current pollutant contribution to allow room for future
loading increases by that source (in other words, using design capacity of a facility in
setting its WLA). A TMDL may also set aside a gross, unallocated "reserve" (as part of
the overall WLA, the overall LA, or the overall total loading capacity) to account for
increased future pollutant contributions from a variety of existing or future sources. In
all cases, the sum of the WLAs, LAs, the margin of safety (if an explicit load has been
defined), and any reserve capacity must be equal to or less than the loading capacity
(TMDL=IWLA + ILA + MOS + Reserve). The EPA does not support trading of
pollutants considered by the EPA to be persistent bioaccumulative toxics (PBTs).44
In the case of PCB TMDLs for waterbodies where there are no permitted or un-
permitted point source dischargers at the time the TMDL is established, inclusion of a
reserve capacity in a TMDL's WLA could allow for permits for newly identified sources.
A reserve for future pollutant contributions from point sources may be included in the
TMDL as a WLA. The EPA regulations require that a TMDL include WLAs, which
identify the portion of the loading capacity allocated to the individual existing and future
point source(s) [40 CFR §130.2(h), 40 CFR §130.2(i)]. Reserve capacity may be
incorporated into the individual WLA of each individual point source. One method is to
allocate a WLA at design flow of a facility when the facility is currently permitted under
capacity. Individual WLA reserves may also be expressed as a percentage of the initial
WLA as calculated in the Delaware River Estuary Volatile Organics and Toxicity
TMDLs.45
It may be reasonable to express allocations from multiple point sources as a single
categorical WLA when data and information are insufficient to assign each source or
44 USEPA "Final Water Quality Trading Policy," January 2003, available at
http://www.epa.aov/owow/watershed/trading/finalpolicv2003.html.
4^
Wasteload Allocations for Volatile Organics and Toxicity: Phase I TMDLs for Toxic Pollutants in the Delaware River Estuary,
December 1998, available at http://www.state.ni.us/drbc/regs/wlareport.pdf.
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outfall individual WLAs.46 In a PCB TMDL, it may thus be reasonable to set aside a
gross WLA reserve to account for the following PCB point source loadings: (a) post-
TMDL identified discharges from existing NPDES permittees that were not captured in a
specific WLA (in other words, newly identified discharges from NPDES permittees that
did not have PCB limits previously); and (b) newly identified dischargers (those not
holding any NPDES permits previously).
Protecting Local Water Quality
Where a TMDL includes an aggregate allocation, states are strongly encouraged to
include specific information on how NPDES permits, including stormwater permits, will
be implemented. It is recommended that the TMDL specifically state that, at the time of
permit issuance, an analysis will be conducted to determine that there will be no
localized exceedances of the WQS. For example, three stormwater outfalls are located
in hypothetical Smith Creek watershed with an aggregate allocation of 30 units per day.
One outfall is considerably closer to Smith Creek than the other two and wants a larger
allocation of 12 units per day. The two remaining outfalls would then have an allocation
of 9 units per day each. These allocations may be appropriate as long as they will not
be contributing to localized exceedances of the WQS or designated uses at any of the
three outfalls. Another option, using the same three stormwater outfalls, would be to
assign a smaller allocation to the closer outfall to Smith Creek if necessary to implement
WQS and designated uses due to the proximity of the outfall to the impaired waterbody.
IX. Load Allocation (LA)
TMDLs include a LA, which identifies the portion of the loading capacity attributed to
existing and future nonpoint sources and natural background. LAs may range from
reasonably accurate estimates to gross allotments [40 CFR §130.2(g)].
As described in VIII above, contributions from NPDES-permitted stormwater sources
that include contributions from air deposition should be included in the WLA.
Contributions from air deposition in stormwater discharges not currently subject to
NPDES regulation may be included in the LA.47
As with WLAs, the LAs should be expressed as a daily load; however, given
bioaccumulative properties of PCBs, TMDL writers may wish to express allocations as
both an annual and daily load.
X. Margin of Safety (MOS)
TMDLs include an MOS to account for uncertainty in relationship between pollutant
loads and quality of receiving water [CWA §303(d)(1 )(C), 40 CFR §130.7(c)(1)]. As
described in existing guidance, the MOS may be implicit (conservative assumptions in
46
"Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit
Requirements Based on Those WLAs," November 22, 2002, available at http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf.
47 See "Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES
Permit Requirements Based on Those WLAs," November 22, 2002, available at http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf.
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the calculations or overall approach) or explicit (e.g., build in additional percent load
reduction). For an implicit MOS, the TMDL should describe the assumptions used to
account for the MOS. The MOS in a TMDL is distinct from the conservative
assumptions that may be incorporated into a WQS.
Implicit MOS
Examples of implicit MOS in PCB TMDLs include, but are not limited to, the following:
• Conservative approach to derive fish tissue target48
• Conservative assumptions of (1) mass assumed to be completely conserved as it
passes through the study area and (2) existing OH River tributary loadings
estimated using conservative approach49
• Combination of several conservative assumptions, including (1) selecting the
greater percent reduction required of water or fish tissue concentrations as the
basis for determining the percent reduction required in sediment, (2) ensuring
protection of downstream subwatersheds from upstream inputs by reducing the
allowable concentration for upstream subwatersheds where downstream allowable
concentrations are lower, (3) decision to use the lower of the allowable
concentration or the numeric target for sediment as the WLA and LA for all
reaches with 303(d) listings for sediment.50
Explicit MOS
A range of explicit MOS values from five percent to 20% of the total loading were
observed in the sample of TMDLs below. The choice of a specific, explicit MOS will
depend on the facts of each particular TMDL. States are encouraged to document and
explain the basis for the particular MOS value they choose.
The Palouse River Chlorinated Pesticide and PCB TMDL51 recognizes the uncertainties
associated with stormwater and WWTP loading of PCBs and dieldrin, and includes a
safety margin of 20% of the loading capacities of the South Fork and mainstem Palouse
River.
Within the Newport Bay and San Diego Creek TMDLs for toxic pollutants52, a 10%
explicit MOS was applied to account for uncertainties in the analysis. A 10% MOS was
subtracted from the loading capacity or existing load, whichever was the smaller value.
An explicit MOS was deemed appropriate because of significant uncertainty in the
analysis of pollutant effects, loads, fate (i.e., chemical transformations and degradation
following discharge), and transport in the watershed. The data supporting the TMDLs
48
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbavpcbs/Staff Report.pdf.
49
Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.aov/reg3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
Calleguas Creek Watershed OC Pesticides and PCBs TMDL Technical Report, June 20, 2005, available at
http://www.waterboards.ca.gov/losanaeles/board decisions/basin plan amendments/technical documents/2005-
010/05 0426/OC 6 TechnicalReport.pdf.
Palouse River Chlorinated Pesticide and PCB Total Maximum Daily Load Water Quality Improvement Report and Implementation
Plan, July 2007, available at http://www.ecv.wa.gov/pubs/0703018.pdf.
Total Maximum Daily Loads For Toxic Pollutants San Diego Creek and Newport Bay, California, June 14, 2002, available at
http://www.waterboards.ca.gov/santaana/water issues/programs/tmdl/docs/sd crk nb toxics tmdl/summarv0602.pdf.
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were somewhat limited. Additionally, for all pollutants the TMDLs also incorporate an
implicit MOS because numerous conservative assumptions were made to ensure that
the analytical methods applied are environmentally protective.
The Delaware River Basin Commission's (DRBC's) Toxic Advisory Committee
recommended use of an explicit MOS of five percent within the Stage 1 PCB TMDLs.
This recommendation, which was adopted in the TMDLs, was based upon the use of a
one-year cycling period for the hydrodynamic and water quality model. Since the
conditions under which the TMDL is determined, like tributary flows, are related to the
long-term conditions and not to design conditions associated with human health WQS
for carcinogens (such as the harmonic mean flow of tributaries), expression of the MOS
as an explicit percentage of each zone TMDL was considered more appropriate than an
implicit MOS.
XI. Critical Conditions and Seasonal Variation
TMDL calculations take into account critical conditions for stream flow, loading and
water quality parameters [40 CFR §130.7(c)(1)]. For PCBs, critical conditions might be
based upon freshwater flow rates due to precipitation regardless of season. Thus, the
applicable allocation for a given source does not depend on time of year, but on actual
stream flow (or associated sediment disposition rate for organochlorine compounds) at
time of discharge. Wet weather events, which may occur at any time of the year,
produce extensive sediment redistribution and transport downstream. This would be
considered the critical condition for loading; however, the effects of organochlorine
compounds are manifested over long time periods in response to bioaccumulation in the
food chain. Therefore, short term loading variations (within the time scale of wet and dry
seasons each year) are not likely to cause significant variations in beneficial use effects.
The Newport Bay and San Diego Creek TMDLs53, for example, consider seasonal
variations in loads and flows but are established in a manner that accounts for the
longer time horizon in which ecological effects may occur.
As PCBs bioaccumulate over time, annual variations may be considered more important
than seasonal variations, particularly if a fish tissue target is used. States are
encouraged to indicate how, when, and where fish tissue data were collected.
XII. Reasonable Assurance
When a TMDL is developed for waters impaired by point sources only, the issuance of
an NPDES permit provides the reasonable assurance that the WLAs contained in the
TMDL will be achieved. This is because 40 CFR 122.44(d)(1)(vii)(B) requires that
effluent limits in permits be consistent with "the assumptions and requirements of any
available wasteload allocation" in an approved TMDL.
53
Total Maximum Daily Loads For Toxic Pollutants San Diego Creek and Newport Bay, California, June 14, 2002, available at
http://www.waterboards.ca.gov/santaana/water issues/programs/trndl/docs/sd crk nb toxics tmdl/summarv0602.pdf.
^4
May 2002 "Guidelines for Reviewing TMDLs Under Existing Regulations Issued in 1992," available at
http://water.epa.gov/lawsreas/lawsauidance/cwa/tmdl/final52002.cfm.
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When a TMDL is developed for waters impaired by both point and nonpoint sources,
and the WLA is based on an assumption that nonpoint source load reductions will
occur, the EPA's 1991 TMDL Guidance states that the TMDLs should provide
reasonable assurances that nonpoint source control measures will achieve expected
load reductions in order for the TMDL to be approvable. This information is necessary
for the EPA to determine that the TMDL, including the LAs and WLAs, has been
established at a level necessary to implement WQS. The EPA's August 1997 TMDL
Guidance also directs Regions to work with states to achieve TMDL LAs in waters
impaired only by nonpoint sources. 55
For TMDLs for PCB-impaired waters, the reasonable assurance demonstration is
challenging because of the nature of the sources and the inability to trade allocations
among nonpoint and point sources. Each TMDL's demonstration of reasonable
assurance is, of necessity, case-specific and therefore states are encouraged to contact
their EPA Region.
XIII. Post-TMDL Monitoring
States are encouraged to implement a multi-media monitoring program, commensurate
with prevalence and availability of PCBs, budget, and other priorities, to track progress
in reducing emissions and loadings from PCB source categories and, in turn, to track
progress toward the TMDL target.
Where discharge data on particular sources or source categories is not available when
developing the TMDL, follow-up monitoring by those sources is encouraged. Further
monitoring can assist in refining the loading estimates and allocations using an adaptive
management approach. States are encouraged to implement as many elements of a
multi-media program as possible to reduce PCB loadings, depending on resources.
A monitoring plan should identify which parameters will be monitored and the frequency
of monitoring. States may also wish to identify a baseline against which to measure
progress.
Delaware River Estuary
The 2003 Stage 1 TMDLs for PCBs within the tidal Delaware River Estuary anticipate
that facilities that discharge to the river, including its tributary streams, will develop and
implement a pollutant minimization plan (PMP) . This PMP is expected to include a list
of all known and suspected point and nonpoint sources of PCBs, a description of
studies used to track down PCBs (i.e., evaluate the most appropriate sampling and
analytical techniques for identifying PCB contamination to the municipal utility authority
May 2002 "Guidelines for Reviewing TMDLs Under Existing Regulations Issued in 1992," available at
http://water.epa.gov/lawsreas/lawsauidance/cwa/tmdl/final52002.cfm.
Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, December 15,
2003, available at http://www.epa.gov/reg3wapd/tmdl/pa tmdl/DelawareRiver/TMDLreport.pdf.
PCB TMDLs, Pollution Minimization Plans, and Source Trackdown in Camden City, August 2008, available at
http://www.state.ni.us/dep/dsr/health/trackdown-rps.pdf.
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PCB TMDL Handbook
(MUA) collection system and identifying upland sources), a description of actions to
minimize the discharge of PCBs, and a proposed time frame for PCB load reductions.
Innovative methods explored in this study included the use of PCB analytical Method
1668a to attain high sensitivity in sampling, including quantification of 124 separate PCB
congeners as a means to identify unique source signatures, the use of passive in-situ
continuous extraction samplers (PISCES) for sample integration over long time periods
(14 days), the use of inexpensive immunoassay techniques for sampling PCBs in street
soils, and the use of NJ Department of Environmental Protection's hazardous waste
site's electronic data collection system in conjunction with a geographic information
system (CIS) to screen and isolate potential upland sources for further investigation.57
The pilot study was carried out in two phases. Phase 1 involved only in-sewer sampling
of wastewater to identify sewersheds with PCB hotspots. Phase 2 followed up on this
sampling with additional in-sewer sampling but also with more detailed street soil
sampling for PCBs in front of suspect facilities.
Ohio River
The Ohio River PCB TMDL58 states that initial actions were to be focused on
addressing current point sources of PCBs. Limited sampling identified publicly owned
treatment works (POTWs) as possible point sources. Additional monitoring was deemed
necessary to better quantify the loadings from these facilities. Once loadings are
established possible control strategies can be considered.
Limited high-volume water sampling conducted on the effluent at two municipal
wastewater treatment plants within the TMDL study area revealed the presence of
PCBs. Similar results were found at another POTW downstream of the study area.
Considering the large number of POTWs within the entire Ohio River Basin, the
potential loadings from these facilities may be significant. The TMDL recommended
additional monitoring be conducted to more accurately quantify the PCB loads
discharged from POTWs and to determine the amount of PCBs attributable to source
water loadings.
XIV. Implementation
An implementation plan is not a federally-required element of a TMDL that is subject to
EPA approval. However, a TMDL implementation plan is required in some states as a
matter of state law. The EPA encourages states to develop an implementation plan for
PCB TMDLs even where one is not required. In addition to implementing PCB TMDLs
through NPDES permits, a number of additional implementation authorities, sources,
and approaches, which could be involved in development of implementation plans for
PCB TMDLs, are provided here.
Note Method 1668C: Chlorinated Biphenyl Congeners in Water Soil, Sediment, Biosolids, and Tissue by HRGC/HRMS
guidance, April 2010, available at http://water.epa.gov/scitech/methods/cwa/other.cfm. describes the updated analytical method
version (1668C).
58 Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.gov/reg3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
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PCB TMDL Handbook
Superfund and Toxic Substances Control Act
In implementing a PCB TMDL, the EPA recommends coordinating with the Superfund
Program. TMDLs established by states, territories or authorized Indian tribes may or
may not be promulgated as rules. Therefore, TMDLs established by states, territories,
or authorized Indian tribes, should be evaluated on a regulation-specific and site-
specific basis. EPA-established TMDLs are not promulgated as rules, are not
enforceable, and, therefore, are not appropriate or relevant and appropriate
requirements (ARARs). Even if a TMDL is not an ARAR, it may aid in setting protective
cleanup levels and may be appropriately a TBC ["to be considered"]. Project managers
should work closely with regional EPA Water program and state personnel to coordinate
matters relating to TMDLs. The project manager should remember that even when a
TMDL or wasteload allocation is not enforceable, the water quality standards on which
they are based may be ARARs. TMDLs can also be useful in helping project managers
evaluate the impacts of continuing sources, contaminant transport, and fate and effects.
Similarly, Superfund's remedial investigation and feasibility study may provide useful
information and analysis to the federal and state water programs charged with
developing TMDLs.
The principal federal law regulating PCBs is the Toxic Substances Control Act (TSCA)
and its implementing regulations, including regulations at 40 CFR 76160. EPA
regulations under TSCA allow discharge of water to a treatment works or navigable
waters if the PCB concentration is less than 3 ug/L (parts per billion), or if the
concentration complies with a PCB water discharge limit in the discharger's CWA permit
[40CFR761(b)(1)(ii)].
Although PCBs were banned in 1979, the EPA's regulations under TSCA allow the
inadvertent manufacture of PCBs as the result of some manufacturing processes.
Under the regulations, a manufacturer can have up to 50 ppm PCBs in products leaving
the manufacturing site (except components of detergent bars can only have less than 5
ppm), so long as the annual average concentration in those products is less than 25
ppm, and so long as the manufacturer complies with other restrictions, including proper
disposal of any PCB wastes produced [40 CFR 761.20(b), 761.3]. EPA regulations also
allow the continued use of PCBs in various electrical and other applications, under
certain conditions [40 CFR 761.30].
Examples of Superfund Program response actions that have been initiated to help clean
up waterways and sediments contaminated with PCBs include the Lower Duwamish
Waterway Site Washington and the Hudson River Site in New York (see "Sediment
Sources: Dredging and Excavation" further below).
Air Sources
When developing PCB TMDLs, states are not required to identify contributions from
individual air sources or air source categories; however, identifying such contributions
en
EPA's Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, December 2005, available at
http://www.epa.aov/superfund/health/conmedia/sediment/pdfs/guidance.pdf.
http://www.access.gpo.gov/nara/cfr/waisidx 08/40cfr761 08.html
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PCB TMDL Handbook
can assist in developing a targeted implementation plan. PCBs may be released to the
air from equipment or materials that are still in use, such as transformers and
fluorescent light ballasts; disposal sites containing transformers, capacitors, and other
PCB waste; incineration of PCB-containing wastes, particularly PCB-containing oils;
and redistribution and transport of PCBs already present in the environment.61 For PCB
air sources over which a state has control, particularly the most significant sources,
TMDL implementation may be based on existing delegated and/or approved federal air
program requirements. States are encouraged to address air sources not already
covered by federal requirements. States should also evaluate cumulative emissions
from air sources other than the most prominent (i.e., secondary, tertiary) and adopt
controls as appropriate.
Water Pollutant Minimization Plans (PMPs)
The EPA's existing regulations require NPDES permits to include WQBELs to control all
pollutants or pollutant parameters that the permitting authority determines are or may be
discharged at a level which will cause, have a reasonable potential to cause, or
contribute to an excursion above any state WQS, including state numeric and narrative
criteria for water quality [40 CFR §122.44(d)(1 )(i)]. In the case of waters impaired by
PCBs, states may consider implementing compliance schedules and cost-effective
pollutant minimization plans (PMPs) for wastewater treatment plants and industrial
discharges [see "Pollutant Minimization Plans (PMPs)," below]. For implementation of
the WLA by permitted sources, also see discussion under previous sections VIII
["Wasteload Allocation (WLA)"] and XII ("Reasonable Assurance").
Sediment Sources
TMDL implementation plans might discuss anticipated remediation measures.
Remediation approaches for PCBs include capping and dredging. Descriptions of these
measures and examples within PCB TMDL implementation plans or discussions follow:
Capping
In-situ capping refers to the placement of a subaqueous covering or cap of clean
material over contaminated sediment that remains in place. Caps are generally
constructed of clean sediment, sand, or gravel, but can also include geotextiles,
liners, or the addition of material, such as organic carbon, to attenuate the flux of
contaminants into the overlying water.62 The San Francisco Bay TMDL
discusses cost estimates and potential implications of capping in-bay sediments
for area noise and cultural resources.63
Dredging and excavation
Dredging and excavation are the two most common means of removing
contaminated sediment from a waterbody, either while it is submerged (dredging)
or after water has been diverted or drained (excavation). Both methods typically
"Polychlorinated Biphenyls (PCBs) (Arochlors) ," January 2000, available at http://www.epa.gov/ttn/uatw/hlthef/polvchlo.html.
More details on in-situ capping can be found in EPA's Contaminated Sediment Remediation Guidance for Hazardous Waste
Sites, December 2005, available at http://www.epa.gov/superfund/health/conmedia/sediment/pdfs/guidance.pdf.
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbaypcbs/Staff Report.pdf.
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necessitate transporting the sediment to a location for treatment and/or disposal.
They also frequently include treatment of water from dewatered sediment prior to
discharge to an appropriate receiving waterbody.64 One of the principal
advantages of dredging and excavation is often that, if they achieve cleanup
levels for the site, they may result in the least uncertainty regarding future
environmental exposure to contaminants because the contaminants are removed
from the aquatic ecosystem and disposed in a controlled environment.65 The
San Francisco Bay PCB TMDL discusses the cost of dredging and disposal of in-
bay sediments.66 The challenges of dredging, including high cost and risks of
habitat destruction and resuspension of contaminants are recognized in the Ohio
River TMDL.67
A collection of technical reports on PCB treatment technologies, including sediment
capping, in-situ thermal desorption-destruction of PCBs, and phytoremediation of
persistent organic compounds is available through the EPA's Technology and
Innovation Program68. The EPA, United Nations Environment Programme, and US
Army Engineer Research and Development Center are among the developers of these
resources.
Examples of Superfund contaminated sediment cleanups include the Lower Duwamish
Waterway in Washington and the Hudson River in New York.
The Lower Duwamish Waterway Cleanup Site covers a 5.5 mile waterway that empties
into Elliot Bay in Seattle as well as the 32 square mile basin that discharges into the
Duwamish. Past and present activities have left a legacy of chemical pollution in the
waterway and in the sediment. Pollutants include PCBs, dioxins, furans, and other
chemicals. In 2001-2002, the EPA and Washington Department of Ecology listed the
Lower Duwamish Waterway under the federal Superfund law and Washington's Model
Toxic Substances Control Act because of the health risks to people and animals
exposed to contaminated sediments. Currently, the EPA is overseeing development of
a Feasibility Study and is developing a recommendation for the cleanup. The Proposed
Plan will be available for public comment in early 2012. Meanwhile, PCBs have driven
several of the "Early Action" cleanup areas' sediment investigation and removal plans.69
The Hudson River PCBs Site encompasses a nearly 200-mile stretch of the Hudson
River in eastern New York State from Hudson Falls, New York to the Battery in New
York City. The EPA named this a Superfund site, contaminated by PCBs, in 1984.
More details on in-situ capping can be found in EPA's Contaminated Sediment Remediation Guidance for Hazardous Waste
Sites, December 2005, available at http://www.epa.aov/superfund/health/conmedia/sediment/pdfs/guidance.pdf.
EPA's Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, December 2005, available at
http://www.epa.gov/superfund/health/conmedia/sediment/pdfs/guidance.pdf.
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbaypcbs/Staff Report.pdf.
67 Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.gov/reg3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
"Contaminant Focus: Polychlorinated Biphenyls (PCBs) - Treatment Technologies," available at
http://www.clu-in.org/contaminantfocus/default.focus/sec/Polvchlorinated Biphenvls (PCBsVcat/Treatment Technologies/.
USEPA, "Lower Duwamish Waterway Superfund Site" website, available at
http://vosemite.epa.gov/r10/cleanup.nsf/sites/lduwamish.
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PCB TMDL Handbook
From approximately 1947 to 1977, the General Electric Company (GE) discharged as
much as 1.3 million pounds of PCBs from its capacitor manufacturing plants into the
Hudson River. Since 1976, high levels of PCBs in fish have led New York State to close
various recreational and commercial fisheries and to issue fish consumption advisories,
Phase 1 dredging for Hudson River cleanup took place between May and November
2009 in a six-mile stretch of the Upper Hudson River near Fort Edward in New York.
Phase 1 was designed to address approximately 10 percent of the material to be
dredged over the six-year project timeframe. At the end of Phase 1, an estimated
283,000 cubic yards of PCB-contaminated sediment had been removed from the river.
Phase 2 (final phase) dredging began in June 2011. During this phase of dredging, GE
will remove about 2.4 million cubic yards of sediment from a forty-mile section of the
Upper Hudson River. 70
Multi-media Sources
PCBs can be released from disposal of products discarded as solid waste, ongoing use
of PCB-containing equipment and materials, industrial processes, and other sources.
These releases may have cross-media impacts. Examples of approaches to address
these sources include monitored natural recovery and PMPs (below), as well as working
with industry, local governments, and the general public through outreach and
communication regarding proper disposal of PCB-containing products.
Monitored Natural Recovery (MNR)
Although burial by clean sediment is often the dominant process relied upon for
natural recovery, multiple physical, biological, and chemical mechanisms
frequently act together to reduce risk. Evaluation of MNR should usually be
based on site-specific data, including multiple lines of evidence such as
decreasing trends of contaminant levels in fish, in surface water, and in
sediment. Project managers should evaluate the long-term stability of the
sediment bed and the mobility of contaminants within it. Contingency measures
should be included as part of a MNR remedy when there is significant uncertainty
that the remedial action objectives will be achieved within the predicted time
frame. Generally, MNR should be used either in conjunction with source control
or active sediment remediation.
While this approach to PCB contamination has a relatively low financial cost,
these natural processes act very slowly on persistent, bioaccumulative pollutants
such as PCBs (estimates from Indiana University71 calculate the half-life of PCBs
at between 13 and 17 years and another estimate in the Central Valley puts half-
life at 56 years72).73 MNR involves analyzing the processes that will result in
USEPA, "Hudson River PCBs" website, available at http://www.epa.gov/hudson/.
Venier, M. and Hites, R.A. Time Trend Analysis of Atmospheric POPs Concentrations in the Great Lakes Region Since 1990,
Environ. Sci. Techno!., 2010, 44 (21), pp 8050-8055. Venier, M. and Hites, R.A. Regression Model of Partial Pressures of PCBs,
PAHs, and Organochlorine Pesticides in the Great Lakes' Atmosphere, Environ. Sci. Technol., 2010, 44 (2), pp 618-623.
Total Maximum Daily Load for PCBs in San Francisco Bay Final Staff Report for Proposed Basin Plan Amendment, February 13,
2008, available at http://www.waterboards.ca.gov/sanfranciscobav/water issues/programs/TMDLs/sfbaypcbs/Staff Report.pdf.
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PCB TMDL Handbook
achieving cleanup objectives and monitoring the recovery to ensure that cleanup
is proceeding as expected. MNR has been selected as a component of the
remedy for contaminated sediment at over one dozen Superfund sites.
Historically, at many sites MNR is combined with dredging or in-situ capping of
other areas of a site. Although reduced contamination in sediments following
effective source control has been observed at some of these sites, long-term
monitoring data on fish tissue are not yet available at most sites to document
continued risk reduction.74
When considering MNR versus a more aggressive remedy, Superfund cleanup
levels are based on regulatory standards that constitute ARARs such as WQS, or
where not available or sufficiently protective, based on risk to human health and
the environment. For human health carcinogenic cleanup levels are based on a
10~4 to 10"6excess cancer risk range (i.e., 1/10,000-1/1,000,000 risk range)
with 10"6 as the point of departure. For toxicity endpoint, the cleanup level is
based on a Hazardous Index of one or less. Cleanup levels are set to protect
ecological receptors.
Factors to take into account when considering MNR versus other remedies
include an analysis of the processes that are contributing to achieving the
cleanup levels through MNR, the expected time frame to achieve the protective
levels, and how this compares against other more active remedies. General
factors for evaluation of MNR need to be evaluated on a case-by-case basis.
Examples of site conditions that might support use of MNR may include such
factors as the sediment bed is reasonably stable and likely to remain so, and
sediment is resistant to resuspension (e.g., cohesive or well-armored sediment).
Several PCB TMDLs consider natural recovery within their implementation
sections. For example, the Ohio River TMDL looks toward addressing PCB
contamination present in sediments; options include natural attenuation.75 An
ongoing annual fish tissue monitoring program makes data and information
available to assess and define current and future long-term trends in PCBs in the
Ohio River system.76 Fish tissue monitoring measures trends and natural
attenuation progress; it provides information on impacts from sediment
concentration (atmospheric deposition may also affect fish tissue concentration).
Pollutant minimization plans (PMPs)
In the case of waters impaired by PCBs, states may consider implementing cost-
effective PMPs.
For PCB control, a PMP might include identification of all known and suspected
point and nonpoint sources of PCBs, a description of studies used to identify
73 Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.gov/rea3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
74
Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, December 2005, available at
http://www.epa.aov/superfund/health/conmedia/sediment/pdfs/guidance.pdf.
Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.gov/reg3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
These data can be found on Ohio River Valley Water Sanitation Commission's website at http://www.orsanco.org/fish-tissue/193.
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PCB TMDL Handbook
PCB sources, a description of actions to minimize prospective discharge of
PCBs, a proposed time frame for PCB load reductions, a method to demonstrate
progress, and ongoing PCB monitoring. As an example, PMP elements for
PCBs were identified in a DRBC resolution and guidance manual77. DRBC has
aggregated resources for completing and implementing PMPs - including a
handbook on PCBs in electrical equipment, a report on technological feasibility
for proposed water quality criteria for NJ, and a NJ pilot "trackdown" program for
PCBs in the sewer system - on its website78.
The primary objective of a recent Camden PCB trackdown study was to identify
PCB sources entering storm drains and CSOs in order to abate PCB transport to
the Delaware River, thereby decreasing bioaccumulation in foodfish and
decreasing risk to human consumers. To that end, the State of New Jersey
narrowed down the universe of potential PCB sources in Camden County MUA's
collection system from a county-wide range of potential sources and
municipalities to just a few specific neighborhoods, industry types and streets in
Camden City (77% of PCB load). Methods used included soil collection,
enzyme-linked immunosorbent assays (ELISA), and high resolution gas
chromatography/high resolution mass spectrometry. 79
DRBC's80, recommended actions to minimize known and probable on-site PCB
sources include the following:
• Removal;
• Engineering controls (such as caps and containment dikes);
• Fluid changeout;
• Substitutions / modifications of raw or finished materials used in the
treatment process;
• Modifications to material handling including transport; and
• Remedial activities for spills and leaks (current or legacy).
Recommended minimization activities for probable collection system sources
include the following81 82:
• Indirect Discharge Permit review and amendment;
• Recommendations for improved and upgraded industrial pre-treatment;
• Remedial activities for spills and leaks (current or legacy);
• Recommendations for remediation by other agencies under other
regulatory programs; and
• Hydraulic controls to minimize PCB mass loads through CSOs.
Pollution Minimization Plans, and Source Trackdown in Camden City, August 2008, available at
http://www.state.ni.us/dep/dsr/health/trackdown-finalreport.pdf.
Available at http://www.state.ni.us/drbc/PMP Resources/index.htm.
79
PCB TMDLs, Pollution Minimization Plans, and Source Trackdown in Camden City, August 2008, available at
http://www.state.ni.us/dep/dsr/health/trackdown-rps.pdf.
Recommended Outline for Pollution Minimization Plans for Polychlorinated Biphenyls in the Delaware Estuary, January 26, 2006,
available at http://www.state.ni.us/drbc/PMP-POTW-012606.pdf
Recommended Outline for Pollution Minimization Plans for Polychlorinated Biphenyls in the Delaware Estuary, January 26, 2006,
available at http://www.state.ni.us/drbc/PMP-POTW-012606.pdf.
89
Also see 40 CFR Part 403; these regulations set forth requirements for publicly owned treatment works (POTWs) to control
discharges into the collection system and POTW treatment plant, as well as requirements for industries that discharge to the POTW.
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PCB TMDL Handbook
Where appropriate, states may wish to use "adaptive implementation," which is "an
iterative implementation process that makes progress toward achieving water quality
goals while using any new data and information to reduce uncertainty and adjust
implementation activities."83 In implementing a TMDL, states may wish to modify
implementation activities as new information on assumptions in the TMDL, such as
previously uncharacterized dischargers as described in section V, becomes available.
PCB TMDLs have also used a "staged" implementation approach, in which
implementation is staged over a period of time, with reduction goals to be met in several
phases.84
See "Clarification Regarding "Phased" Total Maximum Daily Loads," August 2, 2006, at
http://www.epa.gov/owow/tmdl/tmdl clarification letter.html and Adaptive Implementation of Water Quality Improvement Plans:
Opportunities and Challenges, September 2007, at http://nicholasinstitute.duke.edu/water/aualitv/adaptive-implementation-of-water-
gualitv-improvement-plans-opportunities-and -challenges.
See Total Maximum Daily Loads for Polychlorinated Biphenyls (PCBs) for Zones 2-5 of the Tidal Delaware River, Decem ber 15,
2003, available at http://www.epa.gov/reg3wapd/tmdl/pa tmdl/DelawareRiver/TMDLreport.pdf.
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PCB TMDL Handbook
Appendix: PCB Sources
Table 1. Databases for PCB Sources
Database
Toxic
Release
Inventory
(TRI)
Permit
Compliance
System
(PCS)
National
Priority List
(NPL)
Envirofacts
Warehouse
Database
EPA
Transformer
Registration
and PCB
Activity
Databases
Description
Contains information on
releases of nearly 650
chemicals and chemical
categories from industries,
including manufacturing,
metal and coal mining,
electric utilities, commercial
hazardous waste treatment,
among others.
Provides information on
companies which have
been issued permits to
discharge waste water into
rivers. You can review
information on when a
permit was issued and
expires, how much the
company is permitted to
discharge, and the actual
monitoring data showing
what the company has
discharged.
Lists national priorities
among the known releases
or threatened releases of
hazardous substances,
pollutants, or contaminants
throughout the United
States and its territories.
The NPL is intended
primarily to guide the EPA
in determining which sites
warrant further
investigation.
Provides access to several
EPA databases (e.g., PCS,
TRI) to provide information
about environmental
activities that may affect air,
water, and land anywhere in
the United States.
Provides information on
companies or people who
have PCB transformers, are
conducting business
involving the disposal of
PCBs, or are conducting
research and development
involving PCBs.
Location
www.epa.gov/tri
http://www.epa.go
v/enviro/html/pcs/
http://www.epa.go
v/superfund/sites/g
uerv/basic.htm
(Basic Query)
http://www.epa.go
v/envirofw/
http://www.epa.go
v/epawaste/hazard
/tsd/pcbs/pubs/dat
a. htm
Comments
Other sources for
information on toxic
chemical site
releases:
www. e pa. g ov/tri exp I o
rer
—www.epa.gov/enviro
-www. scorecard. org
—www.rtk.net
--Locate NPL sites,
check their cleanup
progress, and get
information on new
and proposed NPL
sites.
-Query parameters
include contaminant
of concern (e.g.,
PCBs)
Learn more about
environmental
activities in your area
or generate maps of
environmental
information here.
Appendix - Page 1 of 2
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PCB TMDL Handbook
Table 2. General PCB Sources
General
Source
Items
intentionally
containing
PCBs
Industry
Combustion
of PCB-
laden
materials
Environment
al sinks
Inadvertent
generation of
PCBs
Storage and
disposal
facilities
Description
Transformers, capacitors, hydraulic and heat
transfer fluids
Steel manufacturing, power plants, electric lamps,
plastic materials and resins, motors, carbon and
graphite products, wiring devices, communication
equipment, rubber, aluminum foundries
Incinerators of municipal, medical, and hazardous
wastes; sewage sludge, scrap tires, industrial and
utility boilers
Contaminated sediments
-Combination of carbon, chlorine, and high
temperatures can result in PCB generation
-Up to 200 chemical processes may create PCB
byproducts
-Products inadvertently containing PCBs include
paint, inks, ag chemicals, plastics, detergent bars
Storage facilities, wastewater treatment plants,
incinerators, landfills, decontamination facilities,
hazardous waste sites (old products include dust
control agents, adhesives, construction materials,
gaskets, sound deafening felt)
Related Databases
(reference Table 1,
above)
EPA Transformer
Registration and
PCB Activity
Databases
TRI, NPL, EPA
Transformer
Registration and
PCB Activity
Databases
TRI
NPL
TRI, NPL, EPA
Transformer
Registration and
PCB Activity
Databases
Ohio River Total Maximum Daily Load (TMDL) for PCBs, September 2002, available at
http://www.epa.gov/reg3wapd/tmdl/wv tmdl/Ohio/OhioReport.pdf.
Appendix - Page 2 of 2
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