Evaluation of toxicity: Whole-sediment versus overlying-water exposures with amphipodHyalella azteca

Abstract A laboratory study was conducted to evaluate the toxicity of whole-sediment versus overlying-water exposures to the amphipod Hyalella azteca using field-collected sediments. Severe toxic effects (5–63% survival) were observed with amphipods exposed for 10 d in direct contact with sediment. In contrast, amphipods exposed only to overlying water in these sediment exposures did not exhibit any toxic effects.