Ref ID : 3326
Gary L. Anderson, Windy A. Boyd, and Phillip L. Williams; Assessment of sublethal endpoints for toxicity testing with the Nematode Caenorhabditis elegans. Environmental Toxicology & Chemistry 20(4):833-838, 2001
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Toxicity tests in invertebrates often use sublethal endpoints, which may exhibit different sensitivity for various toxicants. Our objective was to characterize the sensitivity of movement, feeding, growth, and reproduction as endpoints for heavy metal toxicity testing with Caenorhabditis elegans. Growth and feeding were assessed in the same nematode samples used assess movement and reproduction. Median effective concentrations (EC50s) for 24-hr exposures to Pb, Cu, and Cd were determined for movement, feeding and growth and a 72-hr EC50 was derived for reproduction. The order toxicity was Cu > Pb > Cd for each endpoint, including lethality and movement. There were no differences in sensitivity among endpoints for any metal. When exposed for 4 hr at (sublethal) concentrations that were 14 times the 24-hr EC50 value, Pb and Cu reduced feeding to the same extent while movement was reduced significantly more by Pb than by Cu. Thus, a difference in sensitivity of endpoints was apparent at 4 hr, which was not evident at 24 hr. These observations suggest potentially different mechanisms of toxicity for 24- and 4-hr tests.