A comparison of acute and chronic toxicity methods for marine sediments

Abstract

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.

Performance and sensitivity of rapid sublethal sediment toxicity tests with the amphipod Melita plumulosa and copepod Nitocra spinipes

“…As the variability in the control data can potentially influence the assessment of toxicity, the selection of the control sediment properties to match those of the test sediments can be more important for sublethal bioassays than acute bioassays [16]. The current results indicate that further caution must be used when interpreting toxicity data of N. spinipes, due to the higher variability in controls than was observed for M. plumulosa.…”

“…Longer exposure durations are expected to provide results that are of greater ecological relevance and amenable to modeling contaminant effects on population dynamics [12][13][14]. However, chronic tests have not always been determined to be more sensitive than acute methods [9,15], and long test durations sometimes result in greater variability in the performance of these tests [9,15,16]. Increased variability usually requires that greater test replication is undertaken to meet quality assurance criteria and this increases labor intensiveness and costs [16].…”

“…However, chronic tests have not always been determined to be more sensitive than acute methods [9,15], and long test durations sometimes result in greater variability in the performance of these tests [9,15,16]. Increased variability usually requires that greater test replication is undertaken to meet quality assurance criteria and this increases labor intensiveness and costs [16]. Chronic methods have been described for a large variety of benthic marine organisms, including 28-d growth and reproduction of the amphipods Leptocheirus plumulosus test [5] and Corophium volutator [8], 20-d growth of the polychaete Neanthes arenaceodentata [17], 14-d reproduction of the copepod Amphiascus tenuiremis [18], and 7-d growth of the juvenile clam Mercenaria mercenaria [19].…”

“…Recently, test procedures have been developed that rapidly assess the potential for chronic effects from sediment contaminants to M. plumulosa [10] and N. spinipes [11]. Both methods are suitable for assessing effects on reproduction and survival following exposure to whole sediments for just 10 d, which is considerably shorter than the 20 to 28-d periods used in most sublethal sediment toxicity tests [9,16].…”

Avoidance of contaminated sediments by an amphipod (Melita plumulosa), A harpacticoid copepod (Nitocra spinipes), and a snail (Phallomedusa solida)

“…The relevance of these common ecotoxicological methods is widely debated in the literature, with chronic test methods often preferred over acute toxicity testing [1,7]. Chronic toxicity tests are considered to offer greater ecological relevance, protection at the population level, increased sensitivity, better prediction of toxicity, and the ability to model population effects [19]. However, chronic toxicity tests generally use long exposure periods that often exceed 20 d [20,21].…”