United States
                        Environmental Protection
                        Agency
 Office Of Water
 (4504F)
EPA /842-F-94-001
February 1995
> EPA           Clean Water Act Section 403
                        A Framework For Ecological
                        Risk Assessment
   Background
   In 1972, Congress passed the Federal Water Pollution
   Control Act, commonly known as the Clean Water Act
   (CWA). Under the CWA, point source discharges (i.e.,
   discharges from municipal and industrial facilities) to
   waters of the United States must obtain a National
   Pollutant Discharge Elimination System (NPDES)
   permit, which requires compliance with technology- and
   water quality-based treatment standards. In addition,
   because of the complexity and ecological significance of
   marine ecosystems, discharges to the territorial seas and
   beyond must also comply with section 403 of the CWA,
   which specifically addresses impacts from such point
   sources on marine resources. The section 403 program
   was one of the first of EPA's programs to incorporate
   ecological risk assessment as part of the evaluation of the
   impacts of point source discharges on the marine
   environment.

   Section 403 Requirements
   Section 403 of the CWA provides that point source
   discharges to the territorial seas, contiguous zone, and
   oceans are subject to regulatory requirements in addition
to the technology- or water quality-based requirements
applicable to typical discharges. The section 403
requirements are intended to ensure that no unreason-
able degradation of the marine environment will occur
as a result of the discharge and to ensure that sensitive
ecological communities are protected. These require-
ments can include ambient monitoring programs
designed to determine degradation of marine waters,
alternative assessments designed to further evaluate the
consequences of various disposal options, and pollution
prevention techniques designed to further reduce the
quantities of pollutants requiring disposal and thereby
reduce the potential for harm to the marine environ-
ment. If section 403 requirements for protection of the
ecological health of marine waters are not met, an
NPDES permit will not be issued.

In assessing the potential effects of a marine discharge
during permit application review, the permitting
authority evaluates the impact of a marine discharge on
the biological community based on ecological, social,
and economic factors. Under the provisions of section
403, the permitting authority can require the permit
applicant to provide the information necessary to
conduct such an evaluation.
                                       Ocean Discharges
                                                             Contiguous
                                                                       Open Ocean
                  Industrial
                  Fuci lily
                                 "Baseline
                                 LEGEND

                         Discharges :iyl subject to section

                          1, 2 (Inside the baseline)


                         [Discharges subject to section 4O3(c)-

                          4. 5 (Municipal and industrial
                             discharges to the territorial
                             MM)
                          3, 6 (Municipal and industrial
                             discharge* To the contiguous
                             zone)

                           7 (Oil and gas operations)

                           8 (Seafood processing)

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Ocean Discharge Guidelines
To implement section 403, EPA developed the Ocean
Discharge Guidelines (40 CFR Part 125, Subpart M
[45 FR 65942, October 3, 1980]), which specify the
ecological, social, and economic factors to be used by
permit writers when they evaluate the impact of a
discharge on the marine  environment. The 10 ocean
discharge guidelines to be considered in determining
whether unreasonable degradation of the marine
environment will occur are as follows:
(1)
(2)
(3)
(4)
(5)
 (6)
Quantities, composition, and potential
bioaccumulation or persistence of the pollut-
ants to be discharged.

Potential transport of the pollutants by
biological, physical, or chemical processes.

Composition and vulnerability of potentially
exposed biological communities, including
    unique species or communities,
    endangered or threatened species, and
    species critical to the structure or function
    of the ecosystem.

Importance of the receiving water area to the
surrounding biological community, e.g.,
    spawning sites,
-   nursery/forage areas,
    migratory pathways, and
-   areas necessary for critical life stages/
    functions of an organism.

The existence of special aquatic  sites, includ-
ing (but not limited to)
    marine sanctuaries/refuges,
-   parks,
    monuments,
    national  seashores,
    wilderness areas, and
-   coral reefs/seagrass beds.

  Potential direct or indirect impacts on
  human health.
                                                    (7)   Existing or potential recreational and commer-
                                                          cial fishing.

                                                    (8)   Any applicable requirements of an approved
                                                          Coastal Zone Management Plan (CZMP).

                                                    (9)   Such other factors relating to the effects of the
                                                          discharge as may be appropriate.

                                                   (10)   Marine water quality criteria.
Much of the information necessary to make these
evaluations is usually already available to the permitting
authority from previous scientific studies, permit
evaluations, or other data collection activities. Addi-
tional information may be requested from the applicant
when necessary to help the permit writer make decisions
regarding  the permit.

In those cases where there is insufficient information to
support a  finding of "no unreasonable degradation,"
applicants must demonstrate that the discharge will not
cause "irreparable harm." When the permitting  author-
ity makes a determination of no irreparable harm, a
permit may be issued while confirmatory data on
ecosystem health are gathered to be evaluated prior to
reissuance of the permit.  These data are collected as
part of a monitoring program to assess the impact of the
discharge on water, sediment, and biological quality, as
well as an assessment of alternative sites for the  dis-
charge or disposal of the wastewater. Data are also
gathered through monitoring compliance with all other
conditions in the permit.

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             Applicant submits request for
             issuance/reissuance of permit
               Evaluation to determine
              unreasonable degradation
                Issue/Reissue permit
                May require:
                —Limits
                —Monitoring
                —Special conditions
          Section 403 decision process.

EPA has identified more than 300 facilities subject to
section 403 requirements under individual permits.
Approximately 2,500 oil and gas exploration and
production platforms must also meet section 403
requirements. These facilities are covered in five
general permits in Alaska and the Gulf of Mexico. One
general permit issued in Alaska covers approximately
300 seafood processing facilities, including both land-
based facilities and seagoing vessels.
                                                         403 Authority
                              Statutory Authority:  Section 403 of the Clean Water
                              Act (33 U.S.C. Section 1343).

                              Regulatory Authority: Ocean Discharge Criteria —
                              Title 40, Part 125, Subpart M, Code of Federal
                              Regulations (40 CFR 125.120-125.124).

                              Regulated Community:  Point sources (i.e., industrial
                              and municipal facilities) discharging seaward of the
                              baseline of the territorial sea.

                               Key Section 403 Definitions
                              Unreasonable Degradation

                              •  Significant adverse changes in ecosystem diversity,
                                  productivity, and stability of the biological commu-
                                  nity within the area of discharge and surrounding
                                  biological communities;

                              •  Threat to human health through direct exposure to
                                  pollution or through consumption of exposed
                                  aquatic organisms; or

                              •  Unreasonable loss of aesthetic, recreational,
                                  scientific, or economic value in relation to the
                                  benefit derived from the discharge.

                              Irreparable Harm

                              •  Significant undesirable effects that are irreversible
                                  after cessation or modification of the discharge.

                              Baseline

                              •  Defines  the innermost boundary of the territorial
                                  seas; generally, the mean low water mark.
              The 403 Universe:
    Types of Permitted Discharges (1994)
  Category
Approximate Number
  POTWs
  Offshore Oil and Gas Facilities
  Seafood Processors
  Offshore Placer Mining
  Log Transfer Facilities
  Seawater Treatment Plants
  Sugar Cane Mills
  Petroleum Refineries
  Pulp and Paper Mills
          130
        2,500
          300
            2
           35
            3
            8
            3
            2
                               Ecological Risk Assessment and the
                               403 Process
As described by EPA in its Framework for Ecological
Risk Assessment (1992), ecological risk assessment is
the evaluation of the likelihood that adverse ecological
effects might occur as a result of exposure to one or
more environmental stressors.  An environmental
stressor is any physical, chemical, or biological factor
that can cause an adverse environmental effect.
Common environmental stressors include pollutants
such as pesticides and organic chemicals, loss or

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 alteration of habitat, and sudden or extreme changes
 in temperature. Ecological effects commonly evalu-
 ated include mortality and reproductive or develop-
 mental abnormalities in fish, marine mammals, and
 other marine organisms; the types and magnitude of
 those effects; and the likelihood of recovery. Ecologi-
 cal risk assessment also involves evaluating ecologi-
 cal sustainability.  Ecological sustainability entails
 balancing ecological risks with socioeconomic factors
 to determine an acceptable level of health and quality
 of an ecological system.

 Under the National Pollutant Discharge Elimination
 System (NPDES) program, dischargers must achieve
 compliance with national minimum technology-based
 treatment requirements and any additional  require-
 ments necessary to meet state water quality standards.
 This approach helps to ensure that the designated
 uses of the receiving waters (e.g., fishable,  swim-
 mable) are not impaired.  Section 403 can be used to
 require an evaluation of ocean discharges that looks
 beyond potential for water quality degradation.
 Specifically, section 403 provides for evaluation of the
 ecological risks and impacts associated with the
 discharge. The 10 guidelines listed earlier  incorpo-
 rate not only water quality impacts, but also impacts
 on the biological community and human health.

 To assess potential impacts posed by a discharge, site-
 specific determinations of the magnitude of potential
 ecological risks are made.  For example,  a discharge
 might not cause long-term water quality  degradation,
 but it might contain levels of contaminants that are
 harmful to marine organisms or entire marine
 communities in the vicinity of the  discharge, espe-
 cially benthic (bottom) communities, such as coral
 habitat, seagrass meadows, or shellfish beds.  These
 communities are important individually and also
 make up  part of the entire ecosystem, which directly
 or indirectly affects human health, (e.g., fish con-
 sumption, human  contact, etc.).  By measuring and
 evaluating ecological health—in this case,  marine
 plant and animal life—we can better understand  the
 risks and impacts pollutants pose to human health
and welfare and make informed permitting decisions.

Our natural resources are not unlimited.  The  use of
natural resources carries with it an obligation to
protect those resources for the future.  The purpose of
ecological risk assessment is to gain an improved
 understanding of the magnitude and likelihood of
adverse environmental responses to human activities
 so we can make informed decisions based on the  best
scientific data and knowledge.  Ecological risk
assessment, however, does not preclude human
activity in the environment. Rather, when
appropriately carried out, it should be used to identify
situations where ecological sustainability is threatened.
EPA is committed to improving its decision-making
capabilities by using ecological risk assessment technolo-
gies, such as section 403 Ocean Discharge Criteria
Evaluations to protect both human and ecological health
to the greatest extent possible.

Discussions between
Pemi-ee ana EPA
(Planning)








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Adap'.M Tom EPAs Fremewcrtr for Ecological Risk Assessner.t
EPV63C/R-9213C', Fssruary '392
    EPA's framework for ecological risk assessment,
    modified to incorporate the steps for evaluating an
    ocean discharge.
     Contact Information

     U.S. Environmental Protection
     Office of Wetlands, Oceans ar
     Oceans and Coastal Protectio
     401 M Street, SW  (4504F)
     Washington, DC 20460
     (202) 260-8448
I

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