Mixtures of Metals and Polynuclear Aromatic Hydrocarbons May Elicit Complex, Nonadditive Toxicological Interactions

摘要

Studies suggest that metal-PAH interactions may be common among benthic copepods and that strong nonadditive effects observed in binary mixtures may be moderated in more diverse contaminant mixtures. Acute and sublethal mixture toxicology of the contaminants cadmium (Cd), mercury (Hg), lead (Pb), fluoranthene, and phenanthrene was investigated by using two species of meiobenthic harpacticoid copepod, Schizopera knabeni and Amphiascoides atopus. Contaminant effects were delineated using toxic unit methodology and factorial experiments. Adult S. knabeni were tolerant of exposures to the individual contaminants. When S. knabeni were exposed to the metals mixture, Cd-induced lethality was reduced, suggesting an antagonism among the metals. When exposed to a mixture of Cd, Hg, Pb, and phenanthrene, a greater than additive response was demonstrated. A Cd-phenanthrene synergism was observed in both sediment and aqueous exposures. Grazing-rate bioassays suggest a response-additive sublethal toxicology between metals and phenanthrene. Experiments with A. atopus revealed that phenanthrene and fluoranthene are synergistic with Cd.