Water Quality Benchmarks The What’s and Why’s of Their Application 2007 Western Region Pesticide Meeting May 17, 2007

Water Quality Water Quality BenchmarksBenchmarks

The What’s and Why’s of Their The What’s and Why’s of Their ApplicationApplication

2007 Western Region Pesticide Meeting

May 17, 2007


Beginning this year, states Beginning this year, states receiving federal FIFRA funds for receiving federal FIFRA funds for water quality protection (surface water quality protection (surface and groundwater) must evaluate and groundwater) must evaluate 58 pesticides (Pesticides of 58 pesticides (Pesticides of Interest) to determine if any are Interest) to determine if any are to be considered (Pesticides of to be considered (Pesticides of Concern).Concern).


58 total pesticides 58 total pesticides on the list on the list

27 of which have 27 of which have established MCL’s established MCL’s or HAL’s or HAL’s


Pesticide(s) of Concern:Pesticide(s) of Concern:

Pesticide for which a human Pesticide for which a human health or environmental health or environmental reference reference point*point* is likelyis likely to be approached or to be approached or exceeded in localized areas of a exceeded in localized areas of a State or Tribe.State or Tribe.

* MCL’s and HAL’s used as reference points* MCL’s and HAL’s used as reference points


Example:Example:ChlorpyrifosChlorpyrifos Federal HAL Federal HAL 2 ug/L2 ug/L

20% HAL20% HAL .4 ug/L.4 ug/L50% HAL50% HAL 1 ug/L1 ug/L75% HAL75% HAL 1.5 ug/L1.5 ug/L

Various levels trigger escalating management Various levels trigger escalating management activitiesactivities


How are reference points determined How are reference points determined if no MCL or HAL exists?if no MCL or HAL exists?


Health Based Screening Levels (HBSL)

HBSL’s are benchmark concentrations

of contaminants in water that may be of potential concern for human health, if exceeded.


HBSL’s are non-enforceable HBSL’s are non-enforceable benchmarks that were developed benchmarks that were developed by the USGS and USEPA using by the USGS and USEPA using USEPA methodologies for USEPA methodologies for drinking-water guidelines and drinking-water guidelines and human-health toxicity human-health toxicity information.information.


HBSL’s are calculated based on HBSL’s are calculated based on whether the pesticide is whether the pesticide is considered:considered:

1)1) CarcinogenCarcinogen

2)2) Possible CarcinogenPossible Carcinogen

3)3) Non-CarcinogenNon-Carcinogen


Example:Example:

Azinphos-methylAzinphos-methyl No Federal MCL or HALNo Federal MCL or HAL

HBSLHBSL 10 ug/L10 ug/L

20% HBSL20% HBSL 2 ug/L2 ug/L

50% HBSL50% HBSL 5 ug/L5 ug/L

75% HBSL75% HBSL 7.5 ug/L7.5 ug/L

Trigger levels now based on uniform reference pointTrigger levels now based on uniform reference point


Aquatic Life BenchmarksAquatic Life Benchmarks

Water quality benchmarks (ALB’s) Water quality benchmarks (ALB’s) for aquatic life and fish-eating for aquatic life and fish-eating wildlife are estimates of wildlife are estimates of concentrations above which concentrations above which pesticides may have adverse pesticides may have adverse effects on these target groups. effects on these target groups.


Aquatic life benchmarks are based Aquatic life benchmarks are based on a variety of established criteria on a variety of established criteria for acute and chronic effects to for acute and chronic effects to fish, invertebrates, aquatic fish, invertebrates, aquatic vascular and non-vascular plantsvascular and non-vascular plants


http://ca.water.usgs.gov/pnsp/pubs/circ1291/supporting_info.php


In addition to application in In addition to application in evaluating “Pesticides of Concern” evaluating “Pesticides of Concern” HBSL’s and ALB’s will HBSL’s and ALB’s will approximately double the approximately double the “reference point” numbers “reference point” numbers available to states in determining available to states in determining appropriate response to pesticide appropriate response to pesticide occurrences in ground and surface occurrences in ground and surface waters.waters.


Use as support for action under Use as support for action under existing authority, Health existing authority, Health Agencies?Agencies?

If valid…move towards adoption If valid…move towards adoption in State (Water Quality or in State (Water Quality or Drinking Water Standard)Drinking Water Standard)

Additional guidance (federal) to Additional guidance (federal) to states on benchmark use?states on benchmark use?


For more information contact:For more information contact:

Kirk Cook, LG, LHGKirk Cook, LG, LHG

Natural Resource Assessment SectionNatural Resource Assessment Section

Washington Department of AgricultureWashington Department of Agriculture

(360) 902-1936(360) 902-1936

[email protected]@agr.wa.gov

Documents

Water Quality Benchmarks The What’s and Why’s of Their Application 2007 Western Region Pesticide Meeting May 17, 2007