How Can WARP be Used to Assess the Potential for Effects of Pesticides on Humans or Aquatic Life?
The potential for pesticide concentrations in stream water to adversely affect human health or aquatic life is evaluated by NAWQA using screening-level assessments (Gilliom and others, 2006) similar in concept to USEPA screening-level assessments (USEPA, 2004d). The NAWQA screening-level assessments compare site-specific estimates of pesticide exposure ( concentration statistics or concentrations) with water-quality benchmarks derived from standards and guidelines established by USEPA, toxicity values from USEPA pesticide risk assessments, and USGS Health-Based Screening Levels (HBSLs). The USEPA standards, guidelines, and toxicity values were developed by USEPA as part of the Federal process for assessing and regulating pesticides. Screening-level assessments are not a substitute for either risk assessments, which include many more factors (such as additional avenues of exposure), or site-specific studies of effects. Rather, comparisons of measured or estimated concentrations with wat
