Characterizing toxicity of metal-contaminated sediments from the Upper Columbia River, Washington, USA, to benthic invertebrates.

Sediments from the Upper Columbia River, Washington, USA, are contaminated with metals from smelting operations. We conducted short-term and long-term tests with the midge Chironomus dilutus and the amphipod Hyalella azteca and short-term tests with the freshwater mussel Lampsilis siliquoidea with 54 sediments from the Upper Columbia River to characterize thresholds for toxicity of metals to benthic invertebrates. Test sediments were screened for toxicity by comparisons with low-metal reference sediments.