Comparison of marine sediment toxicity test protocols for the amphipodRhepoxynius abroniusand the polychaete wormNereis (Neanthes) arenaceodentata

Abstract

AbstractThe 10‐d amphipod survival toxicity test protocol usingRhepoxynius abroniuswas compared to the 20‐d polychaete worm growth and survival protocol usingNereis (Neanthes) arenaceodentata.Of the 341 sediment samples collected in California and tested over a 2‐year period, 78% significantly inhibitedR. abroniussurvival, whereas 2 and 26% significantly inhibitedN. arenaceodentatasurvival and biomass, respectively. Statistical power associated with each protocol endpoint was determined by calculating the minimum significant difference (MSD) for each test protocol for this data set. The 90th percentile MSDs forR. abroniussurvival andN. arenaceodentatasurvival and biomass were 16, 36, and 56%, respectively. Survival ofR. abroniuswas significantly negatively correlated with a number of toxicants including metals, pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. No significant correlations were determined betweenN. arenaceodentatasurvival or biomass and contaminants measured. Amphipod survival was also negatively correlated with sediment total organic carbon and grain size, but when samples with a high percent fine grain size (>90% fines) were eliminated from consideration, the overall conclusions of the study were not altered. The 10‐d amphipod survival protocol usingR. abroniuswas a more sensitive indicator of toxicity, but the results indicate that this was due to greater statistical power rather than greater sensitivity of the test organisms or endpoints.