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Whole Effluent Toxicity NPDES Program Laura Phillips USEPA - Office of Wastewater Management 202-564-0741,

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Presentation on theme: "Whole Effluent Toxicity NPDES Program Laura Phillips USEPA - Office of Wastewater Management 202-564-0741,"— Presentation transcript:

1 Whole Effluent Toxicity NPDES Program Laura Phillips USEPA - Office of Wastewater Management 202-564-0741,

2 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).

3 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)

4 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/LC 50 ) Chronic = 1.0 TUc (e.g., 100/NOEC) Applying toxicity criteria with allowable dilution Outfall 0.3 TUa 1.0 TUc

5 Office of Water NRFK2001Intro.ppt Major Components of a NPDES Permit  Cover Page  Effluent limitations  Monitoring & Reporting Requirements  Special Conditions  Standard Conditions

6 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: LC 50 or IWC, Chronic: NOEC, IC p )  Steps to Address Toxicity (Accelerated WET testing, TREs/TIEs)

7 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)

8 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)

9 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.

10 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

11 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: or E-mail:  SETAC WET Training Courses Web site:

12 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. (

13 Office of Water NRFK2001Intro.ppt WET National Program Technical Resources Information/Assistance: EPA OW/OWM Web site: EPA OW/OST Web site: EPA Regional Contacts SETAC Web site: including “Frequently Asked Questions” Bulletin Board SETAC WET Expert Advisory Panel: USEPA WET Document Compendium

14 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)

15 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.

16 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.

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