Sublethal And Lethal Effects In Two Marine Organisms, A Juvenile Echinoderm And A Larval Fish, Exposed To Contaminated Sediments

Abstract

A number of federal and state agencies are concerned with assessing the toxicity of sediment-derived xenobiotics to marine organisms. Toxicity is one of the major factors considered when, for example, disposal of dredged sediments from urban waterways is desired. To measure toxic effects of sediments, bioassays that use the marine amphipod, Rhepoxinius abronius (1, 2), the oyster larva, Crassostrea gigas (3), and the luminescent bacterium, Photobacterium phosphoreum (MicrotoxB) (4) have been commonly employed. However, only a limited number of organisms representing few phyla are currently available in bioassays. Mortaliity of organisms is often used to assess the effects of talxicants, but reliance on mortality as the sole measure of toxicity can seriously underestimate deleterious effects of xenobiotics. Sublethal indicators, such as poor growth, may provide more sensitive measures of the effects of toxicants, yet sublethal effects of toxicants on marine: organisms have not generally been well established, and sublethal indicators have rarely been employed in sediment bioassays. Neither has the relative sensitivity of sublethal and lethal effects been rigorously compared.