Whole Effluent Toxicity NPDES ProgramLaura Phillips

USEPA - Office of Wastewater Management202-564-0741, phillips.laura@epa.gov

Office of Water

NRFK2001Intro.ppt

What is Whole Effluent Toxicity (WET) Testing & Why Do it?

What is it? -

WQ-based toxics control method that directly measures the total or aggregate toxic effect (additive, synergistic and antagonistic) of an aqueous sample through the response(s) of exposed aquatic organisms.

Why do it? -

Protects Narrative Criterion (“no toxics in toxic amounts”) & was designed to predict the impact and toxicity of effluents to determine “safe effluent discharge concentrations” with respect to WQS (criteria).

Office of Water

NRFK2001Intro.ppt

EPA Whole Effluent Toxicity (WET) Program

WET - Component of the WQ Integrated Approach

WQ WET Criteria & Standards

NPDES Regulations: 40 CFR Part 122 (i.e., 40 CFR Part 122.44(d)(1)(iv) & (v))

WET Methods (40 CFR Part 136)

NPDES Permit & EPA Regions, Permitting Authorities (45 NPDES States) and Permittees

Consultants (i.e., Labs)

Office of Water

NRFK2001Intro.ppt

Whole Effluent Toxicity Criteria

Narrative - “no toxics in toxic amounts”

Numeric - TSD recommendations or numeric interpretation of Narrative• Acute = 0.3 TUa (e.g.,

100/LC50)

• Chronic = 1.0 TUc (e.g., 100/NOEC)

Applying toxicity criteria

with allowable dilution

Outfall 0.3 TUa

1.0 TUc

Office of Water

NRFK2001Intro.ppt

Major Components of a NPDES Permit

Cover Page

Effluent limitations

Monitoring & Reporting Requirements

Special Conditions

Standard Conditions

Office of Water

NRFK2001Intro.ppt

With Regard to WET - - NPDES Permits Must Specify

Test Species and Method (Fathead Minnow, Acute or Chronic)

Testing Frequency (Representative of the Effluent)

Statistical Endpoints

(Acute: LC50 or IWC, Chronic: NOEC, ICp)

Steps to Address Toxicity (Accelerated WET testing, TREs/TIEs)

Office of Water

NRFK2001Intro.ppt

WET Test Method Selection

Approved acute and chronic methods (40 CFR Part 136)

Must determine:

• Acute or chronic toxicity (based on calculated limits or available dilution)

• Freshwater or marine discharge

• Most appropriate species (e.g., 3 species quarterly for 1 year)

Office of Water

NRFK2001Intro.ppt

WET Monitoring

WET Monitoring Representative of Effluent Discharge: Important for WET reasonable potential determinations & evaluating WET NPDES permit limit compliance

USEPA NPDES Regulations: 40 CFR 122.21(g)(11) 40 CFR Part 122.21(j)(5)

40 CFR Part 122.44 (i) 40 CFR Part 122.48 (b)

USEPA Guidance:• Technical Support Document (TSD) (1991, OWM)

• Interim Guidance for Performance-Based Reductions of NPDES Monitoring Frequencies (4/19/96, OW/OECA)

Office of Water

NRFK2001Intro.ppt

WET Reasonable Potential (RP) Determinations

No WET Data: Use EPA Technical Support Document’s (TSD) statistical approaches to determine if RP exists.

Fewer than ten valid WET data points (per species): EPA’s TSD provides recommended coefficients of variation.

Ten or more valid WET data points: With ten or more valid and representative effluent data points a robust WET RP determination can be done.

Office of Water

NRFK2001Intro.ppt

TSD Steps in Developing WET Permit Limitations

Acute & Chronic Wasteload Allocations

Step 1: Convert Acute WLA to Chronic WLA

(WET only)

Step 2: Calculate LTA for Both

Step 3: Select Lowest LTA

Step 4: Calculate Maximum Daily Load & Average Monthly Limits

WLA = Wasteload Allocation, LTA= Long Term Average

Office of Water

NRFK2001Intro.ppt

NPDES Program Resources

USEPA OWM Catalog of Publications (EPA 830/B-96-001)• Basic Permit Writers’ Manual (EPA/833-B-96-003, 12/96)

• Technical Support Document (EPA/505-2-90-001, 3/91)

USEPA Basic Permit Writer’s Course - Ca (1/03)

OWM Web site: http://cfpub1.epa.gov/npdes or

E-mail: pwcourse@cadmusgroup.com

SETAC WET Training Courses

Web site: setac.org

Office of Water

NRFK2001Intro.ppt

NPDES Program Resources Under Development

NPDES Permit Development Tool (NPDES/PDT):Electronic tool that will allow permit writers to interactively calculate water quality-based effluent limitations for large number of pollutants. Future versions will include the ability to calculate technology-based limits.

Permit Application Software System (PASS):Phase I: Electronic system which allows permittees to electronically prepare NPDES permit applications, print, & mail it to their NPDES permitting authorities. Phase II: System will be enhanced to allow electronic submission to the NPDES permitting authority. (http://cfpub.epa.gov/npdes/pass)

Office of Water

NRFK2001Intro.ppt

WET National Program Technical Resources

Information/Assistance:• EPA OW/OWM Web site: http://cfpub.epa.gov/npdes

• EPA OW/OST Web site: www.epa.gov/waterscience/WET

• EPA Regional Contacts

• SETAC Web site: www.setac.org/wetindex.html including “Frequently Asked Questions” Bulletin Board

• SETAC WET Expert Advisory Panel: www.setac.org

• USEPA WET Document Compendium

Office of Water

NRFK2001Intro.ppt

USEPA WET Document Compendium - Sample List WET Requirements in Municipal Permits (7/85) WET Sample Permitting & Enforcement Guidance (2/89) WET Control Policy (7/94) National Policy Regarding WET Enforcement (8/95) Clarifications Regarding Flexibility in WET Methods (4/96) Clarifications Regarding WET Test Methods & Guidance on Implementing WET

Toxicity in Permits (7/97) TRE Municipal Guidance (8/99) WET Variability Guidance (6/00) WET Test Methods Guidance (7/00) TRE/TIE Clarifications Document (5/01) WET Test Methods Proposed Rule (9/01)

Office of Water

NRFK2001Intro.ppt

Where Do We Go From Here?

Critical Crossroads - Require careful consideration of the issues, maintaining the NPDES base program, & identifying possibilities for appropriate flexibility within existing NPDES regs and the CWA.

Review the Facts - Use facts to cull out non-productive issues so remaining issues are prioritized in a manner that produces results.

Pursue Strategic Pathways or Decisions - To overcome ongoing barriers to effectively implementing the NPDES WET program.

Office of Water

NRFK2001Intro.ppt

Closing Remarks

Move Program Forward Where possible,

reduce controversies and implement the WET program in a manner that fulfills CWA objectives, complies with USEPA NPDES regulations, and is endorsed by stakeholders through their actions and support to the program.