• Relationship to ambient water quality criteria
• Use of aquatic life benchmarks
• OPP aquatic life benchmarks
• Footnotes
• Definitions

Relationship to Ambient Water Quality Criteria

EPA's Office of Pesticide Programs (OPP) and EPA's Office of Water (OW) have responsibilities for evaluating aquatic toxicity data to assess the ecological effects of chemicals in surface water. Effects assessments under both program offices are developed with high quality data according to parallel but somewhat different rigorously peer-reviewed assessment methods.

• OW uses aquatic toxicity data to develop ambient water quality criteria that can be adopted by states and tribes to establish water quality standards under the Clean Water Act. Procedures for deriving the criteria are described in OW’s Guidelines for Deriving Numerical National Water Quality Criteria for Protection of Aquatic Organisms.
• As required by the Federal Insecticide, Fungicide, and Rodenticide Act, OPP uses aquatic toxicity data in its ecological risk assessments to inform pesticide registration decisions. OPP's procedures for conducting pesticide effects assessments are described in the Overview of the Ecological Risk Assessment Process.
• Both the OW and OPP methods assess and characterize effects for protecting aquatic communities.

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Use of Aquatic Life Benchmarks

EPA worked initially with the U.S. Geological Survey to identify aquatic ecotoxicity benchmark values from risk assessments developed by EPA for individual pesticides during previous re-registration programs. The Overview of the Ecological Risk Assessment Process and ecological risk assessments developed for individual pesticides provide an understanding of the ecotoxicity data used to develop benchmarks. Comparing a measured concentration of a pesticide in water with an aquatic life benchmark can be helpful in interpreting monitoring data and in identifying and prioritizing sites and pesticides that may require further investigation.

The toxicity data used to develop aquatic life benchmarks are extracted from the most recent publicly available OPP risk assessment for the individual pesticide and are typically based on the most sensitive value for each taxon. Aquatic life benchmarks are estimates of the concentrations below which pesticides are not expected to represent a risk of concern for aquatic life.

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