What's New for Whole Effluent Toxicity (WET)

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. Introduction to WET • 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

7. Introduction to WET • WET test animals • Fathead minnow • Daphnia magna • Ceriodaphnia dubia

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

9. Introduction to WET • Objective is to prevent toxicity to aquatic life

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

11. Introduction to WET • Something new: Ceriodaphnia isnot the most sensitive aquatic animal!

12. Introduction to WET • More sensitive to sulfates: Amphipod Hyalella azteca

13. Introduction to WET • More sensitive to sodium chloride, ammonia (mussels) Barnhart, M. C.  2006. Unio Gallery:  http://unionid.missouristate.edu.  Accessed 4 11 07

14. Introduction to WET • Mussel egg sacs Barnhart, M. C.  2006. Unio Gallery:  http://unionid.missouristate.edu.  Accessed 4 11 07

15. Introduction to WET Barnhart, M. C.  2006. Unio Gallery:  http://unionid.missouristate.edu.  Accessed 4 11 07

16. Introduction to WET Barnhart, M. C.  2006. Unio Gallery:  http://unionid.missouristate.edu.  Accessed 4 11 07

17. Introduction to WET • Something new: Ceriodaphnia isnot the most sensitive aquatic animal! • More than ever, Michigan considers Ceriodaphnia dubia to be a reasonable surrogate WET test organism

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

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

21. Michigan Regulation of WET/Recent Changes • 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

22. Michigan Regulation of WET/Recent Changes • 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

23. Michigan Regulation of WET/Recent Changes • 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

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

25. Michigan Regulation of WET/Recent Changes • 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. Michigan Regulation of WET/Recent Changes • 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

28. Michigan Regulation of WET/Recent Changes • 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

29. Michigan Regulation of WET • 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

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

31. Maximizing Effect/Minimizing Cost/WET Consultants • 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

32. Maximizing Effect/Minimizing Cost/WET Consultants • 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

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

34. Maximizing Effect/Minimizing Cost/WET Consultants • 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. Maximizing Effect/Minimizing Cost: What you Can Do • 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

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

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

39. Maximizing Effect/Minimizing Cost: What you Can Do • 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

40. MDEQ Aquatic Toxicology Laboratory • Lansing • Bill Dimond, Aquatic Biology Specialist • Diana Butler, Laboratory Technician • Contact (Bill): • 517-327-2622 • dimondw@michigan.gov • Please call or email me anytime