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

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

Water Quality Benchmarks 58 total pesticides on the list 27 of which have established MCL’s or HAL’s

Water Quality Benchmarks Pesticide(s) of Concern: Pesticide(s) of Concern: Pesticide for which a human health or environmental reference point* is likely to be approached or exceeded in localized areas of a State or Tribe. Pesticide for which a human health or environmental reference point* is likely to be approached or exceeded in localized areas of a State or Tribe. * MCL’s and HAL’s used as reference points

Water Quality Benchmarks Example: ChlorpyrifosFederal HAL 2 ug/L 20% HAL.4 ug/L 50% HAL1 ug/L 75% HAL1.5 ug/L Various levels trigger escalating management activities

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

Water Quality Benchmarks 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.

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

Water Quality Benchmarks HBSL’s are calculated based on whether the pesticide is considered: HBSL’s are calculated based on whether the pesticide is considered: 1)Carcinogen 2)Possible Carcinogen 3)Non-Carcinogen

Water Quality Benchmarks Example: Azinphos-methylNo Federal MCL or HAL HBSL10 ug/L 20% HBSL 2 ug/L 20% HBSL 2 ug/L 50% HBSL 5 ug/L 50% HBSL 5 ug/L 75% HBSL7.5 ug/L 75% HBSL7.5 ug/L Trigger levels now based on uniform reference point

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

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

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

Water Quality Benchmarks Use as support for action under existing authority, Health Agencies? Use as support for action under existing authority, Health Agencies? If valid…move towards adoption in State (Water Quality or Drinking Water Standard) If valid…move towards adoption in State (Water Quality or Drinking Water Standard) Additional guidance (federal) to states on benchmark use? Additional guidance (federal) to states on benchmark use?

Water Quality Benchmarks For more information contact: Kirk Cook, LG, LHG Natural Resource Assessment Section Washington Department of Agriculture (360)