A comparison of acute and chronic toxicity methods for marine sediments.

Sediment toxicity tests are valuable tools for assessing the potential effects of contaminated sediments in dredged material evaluations because they inherently address complexity (e.g., unknown contaminants, mixtures, bioavailability). Although there is a need to understand the chronic and sublethal impacts of contaminants, it is common to conduct only short-term lethality tests in evaluations of marine sediments. Chronic toxicity methods for marine sediments have been developed but the efficacy of these methods is less documented. In this evaluation of marine sediments collected from the New York/New Jersey (NY/NJ) Harbor, three 10-d acute toxicity test methods (Ampelisca abdita, Leptocheirus plumulosus, Americamysis bahia) and three chronic and sublethal test methods (28-d L. plumulosus, 20- and 28-d Neanthes arenaceodentata) were applied by three testing laboratories. Although the N. arenaceodentata and A. bahia tests did not indicate significant toxicity for the sediments tested in this study, these methods have been reported useful in evaluating other sediments. The 10-d A. abdita, 10-d L. plumulosus and 28-d L. plumulosus tests were comparable between laboratories, indicating 29-43%, 29%, and 43-71% of the tested sediments as potentially toxic. The 28-d L. plumulosus method was the only chronic toxicity test that responded to the test sediments in this study. The 28-d L. plumulosus endpoint magnitudes were related to sediment chemistry and the sublethal endpoints were reduced as much or more than acute lethality endpoints. However, intra-treatment sublethal endpoint variability was greater, compromising detection of statistical significance. In this study, the chronic L. plumulosus test method was less consistent among laboratories relative to acute test methods, identifying potential for toxicity in a similar number (or slightly more) NY/NJ Harbor sediments.