Toxic effects of selenium and copper on the planarian, Dugesia dorotocephala

Aquatic toxicologists have become increasingly concerned with the effects of sublethal concentrations of toxicants on aquatic organisms. Sublethal effects of toxicants on freshwater invertebrates were reviewed. Selenium (Se) and copper (Cu) are both essential trace elements and toxicants. Se has been reported to alter the toxicity of heavy metals. Planarians, Dugesia dorotocephala, were used as test animals. The objectives of this study were to determine: (1) acute toxicity of Se on planarians and the effect of the number of planarians per test chamber, (2) interaction of the acute toxicity of Se and Cu on planarians, and (3) sublethal effects of Se and Cu on planarians.;Se was acutely toxic to planarians at concentrations as low as 10 mg Se/L. The 96 hr LC;Initially Se appeared to antagonize the effects of Cu toxicity; whereas, later Se appeared to have synergistic effects with Cu on mortality of planarians. Cu was acutely toxic to planarians at concentrations as low as 0.05 mg Cu/L. The 96 hr LC;Interaction of Se and Cu on the measures of sublethal toxicity was not significant. Se did not appear to antagonize the sublethal effects of Cu toxicity on planarians. Se might have a synergistic effect with Cu on the behavior of planarians including the capacity to capture prey. Se separately had few sublethal effects on planarians; whereas, Cu had significant sublethal effects on planarians at concentrations as low as 0.02 mg Cu/L. In conclusion, planarians can be used as a rapid and efficient indicator of sublethal effects of toxicants.