INTERLABORATORY COMPARISON OF A 10-DAY SEDIMENT TOXICITY TEST METHOD USING AMPELISCA-ABDITA, EOHAUSTORIUS-ESTUARIUS AND LEPTOCHEIRUS-PLUMULOSUS

Estuarine and marine amphipods have been chosen by the U.S. Environmen tal Protection Agency (EPA) for use in standardized 10-d sediment toxi city tests. An interlaboratory comparison (round robin) was conducted to evaluate the precision of these methods. This comparison included t hree species, Ampelisca abdita, Eohaustorius estuarius, and Leptocheir us plumulosus. Each species was exposed for 10 d under static, nonrene wal conditions to four sediment treatments using standardized, species -specific test protocols by at least six independent facilities. Sedim ent treatments were selected for each species to include one negative control sediment and three contaminated sediments. Highly contaminated sediment from Black Rock Harbor (BRH), Connecticut, was diluted with species-specific, noncontaminated control sediment, creating test sedi ments that ranged in relative contamination from low to high. Laborato ries showed strong, logical agreement in rank survival for all species , with control sediment consistently exhibiting the highest survival, and sediment with the greatest proportion of BRH consistently exhibiti ng the lowest survival. Although instances of considerable interlabora tory variability occurred, laboratories showed acceptable survival and variability in control sediments, significant agreement in ranking se diment toxicity, and agreement in the categorization of sediments as t oxic or nontoxic for all three species.