title: Copper toxicity to larval Mercenaria mercenaria (hard clam).
abstract: Preset larval Mercenaria mercenaria were exposed to nominal concentrations of 1 (control) to 495 microg Cu/L in artificial seawater and monitored for mortality, activity, development, and metamorphosis in sealed 30-mm plastic petri plates containing 1.5 ml of artificial seawater or toxicant solution. The plastic petri plates sorbed only about 2.6 microg/L at any dose and allowed direct observation of larval clams under a light microscope for a period of two weeks; control survivorship was in excess of 60% at 400 h. The dose-response curve for mortality for clams exposed to copper and fed Isochrysis galbana was characterized by survival similar to or better than controls at doses of 5 and 14 microg Cu/L, while doses of 7 and > or = 29 microg Cu/L exhibited mortality greater than controls. Values of lowest concentration at which 50% of the organisms died (LC50) were 62.4, 21.2, and 11.7 microg Cu/L, and the lowest observed adverse effect concentration values of 57, 29, and 29 microg Cu/L were determined at 48, 96, and 192 h, respectively. In contrast, activity, as judged by swimming, exhibited a typical exponentially decreasing response at these same concentrations. Experiments on the uptake of dissolved copper by I. galbana confirmed literature reports that these algae concentrate copper. Ingesting copper-containing algae was demonstrated to be a source of copper toxicity for larval clams.
authors.affiliation: Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg 24061-0246, USA.
authors.forename: Timothy M C
authors.initials: TM
authors.lastname: Labreche
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Dietrich
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Gallagher
authors.forename: Natalie
authors.initials: N
authors.lastname: Shepherd
mesh_terms: D000818:Animals; D049872:Bivalvia; D003300:Copper / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D007814:Larva / Q000254:growth & development; D008675:Metamorphosis, Biological / Q000187:drug effects; D012995:Solubility; D016019:Survival Analysis; D014873:Water Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D014873:Water Pollutants; D003300:Copper