Transcript What's New for Whole Effluent Toxicity (WET)

What's New for Whole Effluent
Toxicity (WET)
Bill Dimond
MDEQ Aquatic Toxicology
Laboratory
Outline
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
Introduction to WET
How MDEQ regulates WET in the NPDES
Permit Program
– What’s new
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
Maximizing Effect/Minimizing Cost
MDEQ Aquatic Toxicology Laboratory
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)
Introduction to WET
 Bay Harbor CKD
Leachate
Introduction to WET
 WET Test
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
Introduction to WET
 WET test animals
– Fathead minnow
– Daphnia magna
– Ceriodaphnia dubia
Introduction to WET
 WET test animals are surrogates for all
animals in the aquatic ecosystem
Introduction to WET
 Objective is to prevent toxicity to aquatic life
Introduction to WET
 All aquatic life (mussel)
K. S. Cummings of the Illinois Natural History Survey
Introduction to WET
 Something new: Ceriodaphnia is not the
most sensitive aquatic animal!
Introduction to WET
 More sensitive to
sulfates: Amphipod
Hyalella azteca
Introduction to WET
 More sensitive to
sodium chloride,
ammonia
(mussels)
Barnhart, M. C. 2006. Unio Gallery: http://unionid.missouristate.edu. Accessed 4 11 07
Introduction to WET
 Mussel egg sacs
Barnhart, M. C. 2006. Unio Gallery: http://unionid.missouristate.edu. Accessed 4 11 07
Introduction to WET
Barnhart, M. C. 2006. Unio Gallery: http://unionid.missouristate.edu. Accessed 4 11 07
Introduction to WET
Barnhart, M. C. 2006. Unio Gallery: http://unionid.missouristate.edu. Accessed 4 11 07
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
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’
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
R1219 Flow
Diagram
MIXED
1.0 TUc
FLOW
MIXING
1.0 TUa
DISCHARGE POINT
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
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
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
Michigan Regulation of WET/Recent
Changes
 Promulgated WET methods now required
– Daphnia magna chronic method unavailable
(not promulgated)
– Promulgated methods include:
Michigan Regulation of WET/Recent
Changes
 Acute methods (survival)
– Fathead minnow
– Trouts
– Daphnids
Courtesy of Indiana University
Michigan Regulation of WET/Recent
Changes
 Chronic Methods
– Fathead minnow
 Survival
 Growth
– Ceriodaphnia dubia
 Survival
 Reproduction
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
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
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
Maximizing Effect/Minimizing
Cost/WET Consultants
 WET Consultant
choice
– Shop around
 Ask your peers
 Price isn’t everything;
data quality is essential
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
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
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
Maximizing Effect/Minimizing
Cost/WET Consultants
 Does consultant
contact MDEQ if there
are WET test data
quality concerns?
Maximizing Effect/Minimizing Cost:
What you Can Do
 Ensure Data Validity
– Sample during
representative
operations
– But don’t “game”
sampling to avoid
toxicity
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
Maximizing Effect/Minimizing
Cost: What you Can Do
 When toxicity is detected:
– Ensure result is representative
 Review facility operations
 Unusual operations or occurrences
Maximizing Effect/Minimizing
Cost: What you Can Do
 When toxicity is detected:
– Investigate toxicity
 Contact non-domestic users
 New water treatment additive?
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
MDEQ Aquatic Toxicology
Laboratory
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Lansing
Bill Dimond, Aquatic Biology Specialist
Diana Butler, Laboratory Technician
Contact (Bill):
– 517-327-2622
– [email protected]
– Please call or email me anytime