What's New for Whole Effluent Toxicity (WET)

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What's New for Whole Effluent Toxicity (WET)

• Bill Dimond
• MDEQ Aquatic Toxicology Laboratory

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Outline

• Introduction to WET
• How MDEQ regulates WET in the NPDES Permit
  Program
• Whats new
• Maximizing Effect/Minimizing Cost
• MDEQ Aquatic Toxicology Laboratory

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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)

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Introduction to WET

• Bay Harbor CKD Leachate

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Introduction to WET

• WET Test

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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

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Introduction to WET

• WET test animals
• Fathead minnow
• Daphnia magna
• Ceriodaphnia dubia

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Introduction to WET

• WET test animals are surrogates for all animals
  in the aquatic ecosystem

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Introduction to WET

• Objective is to prevent toxicity to aquatic life

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Introduction to WET

• All aquatic life (mussel)

K. S. Cummings of the Illinois Natural History
Survey
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Introduction to WET

• Something new Ceriodaphnia is not the most
  sensitive aquatic animal!

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Introduction to WET

• More sensitive to sulfates Amphipod Hyalella
  azteca

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Introduction to WET

• More sensitive to sodium chloride, ammonia
• (mussels)

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

• Mussel egg sacs

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

• 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

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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

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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

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

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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 gt allowable
  level RP

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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

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Michigan Regulation of WET/Recent Changes

• Promulgated WET methods now required
• Daphnia magna chronic method unavailable (not
  promulgated)
• Promulgated methods include

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Michigan Regulation of WET/Recent Changes

• Acute methods (survival)
• Fathead minnow
• Trouts
• Daphnids

Courtesy of Indiana University
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Michigan Regulation of WET/Recent Changes

• Chronic Methods
• Fathead minnow
• Survival
• Growth
• Ceriodaphnia dubia
• Survival
• Reproduction

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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

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Michigan Regulation of WET/Recent Changes

• NPDES Permit Application now requires WET data
  (1999)
• WWTP with
• gt 1 MGD design flow
• Or
• Federal IPP/Requirement to develop Federal IPP
• Implemented in Michigan NPDES permits

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Michigan Regulation of WET

• What youll 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

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Maximizing Effect/Minimizing Cost/WET Consultants

• WET Consultant choice
• Shop around
• Ask your peers
• Price isnt everything data quality is essential

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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

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Maximizing Effect/Minimizing Cost/WET Consultants

• MDEQ data quality review
• Consultants arent always right
• Ammonia toxicity exaggeration
• Unexplainable concentration-response
• Pathogen interference
• QA/QC problems
• Ask me, anytime. MDEQ wants to use only valid
  WET data

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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

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Maximizing Effect/Minimizing Cost/WET Consultants

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

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Maximizing Effect/Minimizing Cost What you Can Do

• Ensure Data Validity
• Sample during representative operations
• But dont game sampling to avoid toxicity

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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

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Maximizing Effect/Minimizing Cost What you Can Do

• When toxicity is detected
• Ensure result is representative
• Review facility operations
• Unusual operations or occurrences

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Maximizing Effect/Minimizing Cost What you Can Do

• When toxicity is detected
• Investigate toxicity
• Contact non-domestic users
• New water treatment additive?

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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

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MDEQ Aquatic Toxicology Laboratory

• Lansing
• Bill Dimond, Aquatic Biology Specialist
• Diana Butler, Laboratory Technician
• Contact (Bill)
• 517-327-2622
• dimondw_at_michigan.gov
• Please call or email me anytime