Sediment Toxicity to a Marine Infaunal Amphipod: Cadmium and Its Interaction with Sewage Sludge

摘要

The acute toxicity of cadmium to the marine infaunal amphipod, Rhepoxynius abronius, was determined separately in sediment and seawater. Most cadmium added to test sediment was bound to particles and less than 5% was dissolved in interstitial water. The LC50 based on cadmium concentration in interstitial water was similar to the LC50 based on cadmium concentration in seawater without sediment. Cadmium in interstitial water, rather than that bound to particles, therefore appears responsible for acute sediment toxicity to this species. The addition of small quantities of sewage sludge or an increase in the proportion of the fine fraction of sediment particles significantly reduced the toxicity of cadmium in sediment. Binding of cadmium by sediment particles may explain the presence of phoxocephalid amphipods at sites where sewage and metal pollution occur together.