Sediment toxicity testing with the amphipod Ampelisca abdita in Calcasieu Estuary, Louisiana

Toxicity of sediment from the estuary of the Calcasieu River in Louisiana to the benthic amphipod, Ampelisca abdita, was investigated. The estuary is contaminated by discharge from chemical and petrochemical plants on the lower part of the rivers. Sediment from 26 of the 38 sampling sites was significantly toxic to the organism in a ten-day flowthrough test. Sediment samples from bayous dominated by discharge were the most toxic. Organism mortality was related to sediment levels of heavy metals and total organic compounds. Toxicity was unaffected by low salinity of interstitial water or by storage of the sediment prior to testing. The organism was more sensitive to sediment than to receiving water.