Comparisons of sediment toxicity with predictions based on chemical guidelines

The U.S. Environmental Protection Agency (EPA) Environmental Monitoring and Assessment Program–Estuaries and the National Oceanic and Atmospheric Administration Bioeffects Surveys provide large data sets with which to test proposed relationships between sediment chemistry and toxicity. We conclude that guidelines based on bulk chemistry can provide useful triggers for further analysis but should not be used alone as indicators of toxicity. The sediment quality criteria for nonionic organic compounds proposed by the EPA are exceeded in so few samples that they may be of limited practical value. Toxicity was present in many cases when acid-volatile sulfide (AVS) concentrations exceeded the sum of concentrations of sulfide-insoluble metals. However, there is no way to test whether that toxicity was due to those trace elements. The AVS criterion is much more sensitive to AVS concentration than to trace metal contamination.