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What's New for Whole Effluent Toxicity (WET) Bill Dimond MDEQ Aquatic Toxicology Laboratory.

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Presentation on theme: "What's New for Whole Effluent Toxicity (WET) Bill Dimond MDEQ Aquatic Toxicology Laboratory."— Presentation transcript:

1 What's New for Whole Effluent Toxicity (WET) Bill Dimond MDEQ Aquatic Toxicology Laboratory

2 Outline  Introduction to WET  How MDEQ regulates WET in the NPDES Permit Program –What’s new  Maximizing Effect/Minimizing Cost  MDEQ Aquatic Toxicology Laboratory

3 Introduction to WET  Whole Effluent Toxicity (WET) = total toxic (poisonous) effect of an effluent on aquatic animals –Measured by WET test –Aquatic animals exposed to effluent –Measures  Mortality  Growth or reproduction (sub-lethal effects)

4 Introduction to WET  Bay Harbor CKD Leachate

5 Introduction to WET  WET Test

6  Definitions –TUa: acute toxic unit. Amount of acute toxicity measured –TUc: chronic toxic unit. Amount of chronic toxicity measured –Toxic units vary from 0 (not toxic) to as many as 1,000 (paper product spill) or more Introduction to WET

7  WET test animals –Fathead minnow –Daphnia magna –Ceriodaphnia dubia

8  WET test animals are surrogates for all animals in the aquatic ecosystem Introduction to WET

9  Objective is to prevent toxicity to aquatic life

10  All aquatic life (mussel) K. S. Cummings of the Illinois Natural History Survey Introduction to WET

11  Something new: Ceriodaphnia is not the most sensitive aquatic animal! Introduction to WET

12  More sensitive to sulfates: Amphipod Hyalella azteca

13 Introduction to WET  More sensitive to sodium chloride, ammonia (mussels) (mussels) Barnhart, M. C Unio Gallery: Accessed http://unionid.missouristate.edu

14  Mussel egg sacs Introduction to WET Barnhart, M. C Unio Gallery: Accessed http://unionid.missouristate.edu

15 Introduction to WET Barnhart, M. C Unio Gallery: Accessed http://unionid.missouristate.edu

16 Introduction to WET Barnhart, M. C Unio Gallery: Accessed http://unionid.missouristate.edu

17  Something new: Ceriodaphnia is not the most sensitive aquatic animal!  More than ever, Michigan considers Ceriodaphnia dubia to be a reasonable surrogate WET test organism Introduction to WET

18 Michigan Regulation of WET WET regulation required by rule  R1057(1), Michigan Natural Resources and Environmental Protection Act: ‘Toxics shall not be present at levels which are or may become injurious...’  R1057(6): ‘Whole-effluent toxicity requirements may be used to ensure... requirements are met’

19  R1219: Whole Effluent Toxicity –Interprets 1057(6) narrative criterion:  Allows 1 TUa at point of discharge  Allows 1 TUc after mix Michigan Regulation of WET

20 FLOW MIXED MIXING 1.0 TUa R1219 Flow Diagram 1.0 TUc DISCHARGE POINT

21  Reasonable Potential (RP) (2000) –Statistical determination of potential to exceed allowable WET level –Comparison of worst-case toxicity x multiplier against allowable WET –A finding of RP requires a WET Limit by Rule Michigan Regulation of WET/Recent Changes

22  Reasonable Potential (RP) –Only representative data are to be used –More tests reduce uncertainty, and therefore multiplier –But if any representative result > allowable level = RP Michigan Regulation of WET/Recent Changes

23  Reasonable Potential –WET Limit not a death sentence  WET testing is expensive  Monitoring frequency reduction reduces costs –Lobby for this is in NPDES permit  RP will be recalculated at next permit cycle Michigan Regulation of WET/Recent Changes

24  Promulgated WET methods now required –Daphnia magna chronic method unavailable (not promulgated) –Promulgated methods include: Michigan Regulation of WET/Recent Changes

25  Acute methods (survival) –Fathead minnow –Trouts –Daphnids Courtesy of Indiana University

26 Michigan Regulation of WET/Recent Changes  Chronic Methods –Fathead minnow  Survival  Growth –Ceriodaphnia dubia  Survival  Reproduction

27  Alpha 0.01 (ca. 2000) –Used for most controversial/sensitive endpoints  Ceriodaphnia dubia reproduction  Fathead minnow growth –Raises the bar for finding toxicity by reducing the statistical chance of a false positive –Objective: use valid data for WET regulation Michigan Regulation of WET/Recent Changes

28  NPDES Permit Application now requires WET data (1999) –WWTP with:  > 1 MGD design flow  Or  Federal IPP/Requirement to develop Federal IPP –Implemented in Michigan NPDES permits Michigan Regulation of WET/Recent Changes

29  What you’ll see in NPDES Permits –Nothing –Annual WET monitoring (permit app requirement) –WET Monitoring –WET Limit (RP) –Toxicity Reduction Evaluation (TRE) –WET consultant generally required, especially for TRE work Michigan Regulation of WET

30 Maximizing Effect/Minimizing Cost/WET Consultants  WET Consultant choice –Shop around  Ask your peers  Price isn’t everything; data quality is essential

31  WET consultant recommendations –Contract: who pays if test QA/QC fails? –Chronic tests: Does consultant use Alpha 0.01 for statistical analyses? –How does consultant address:  ammonia toxicity exaggeration  pathogen interference Maximizing Effect/Minimizing Cost/WET Consultants

32  MDEQ data quality review –Consultants aren’t always right  Ammonia toxicity exaggeration  Unexplainable concentration-response  Pathogen interference  QA/QC problems –Ask me, anytime. MDEQ wants to use only valid WET data Maximizing Effect/Minimizing Cost/WET Consultants

33  Consultants may help with Reasonable Potential (RP) concerns –If toxicity is detected, ask consultant if RP will be indicated –Or, you may ask me Maximizing Effect/Minimizing Cost/WET Consultants

34  Does consultant contact MDEQ if there are WET test data quality concerns?

35 Maximizing Effect/Minimizing Cost: What you Can Do  Ensure Data Validity –Sample during representative operations –But don’t “game” sampling to avoid toxicity

36  Use clean sampling equipment/avoid sample contamination  Ice samples well  If ammonia is present in sample, inform WET consultant –Test design can be modified to reduce ammonia toxicity exaggeration Maximizing Effect/Minimizing Cost: What you Can Do

37  When toxicity is detected: –Ensure result is representative  Review facility operations  Unusual operations or occurrences Maximizing Effect/Minimizing Cost: What you Can Do

38  When toxicity is detected: –Investigate toxicity  Contact non-domestic users  New water treatment additive? Maximizing Effect/Minimizing Cost: What you Can Do

39  When toxicity is detected: –Ask consultant what can be done  To investigate toxicity  Effect on next NPDES permit –And/or ask my office what can be done Maximizing Effect/Minimizing Cost: What you Can Do

40 MDEQ Aquatic Toxicology Laboratory  Lansing  Bill Dimond, Aquatic Biology Specialist  Diana Butler, Laboratory Technician  Contact (Bill): – –Please call or me anytime


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