WP16 Sediment Quality Assessment
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(BAY-1117-845727) Comparison of marine amphipod test species responsiveness to contaminated field sediments.

Bay, S¹, Gries, T², Anderson, B³, Phillips, B³, Field, L⁴, Moore, D⁵, Greenstein, D¹, ¹ Southern California Coastal Water Research Project, Westminster, CA, USA² Washington State Department of Ecology, Olympia, WA, USA³ University of California at Davis, Davis, CA, USA⁴ National Oceanic and Atmospheric Administration, Seattle, WA, USA⁵ Weston Solutions, Carlsbad, CA, USA

ABSTRACT- Marine and estuarine sediment quality evaluations commonly use standardized 10-day acute toxicity tests that expose a species of amphipod to whole sediment samples. Four species are commonly in assessment and regulatory programs, with the selection of the species based on factors such as habitat characteristics, availability, past use, and program specifications. It is frequently assumed that the amphipod test species exhibit relatively similar response to sediment contaminants and the data are therefore comparable. However, marine sediment toxicity data sets collected from different regions of the country over the past several years have called this into question, and prompted inquiry into the comparability of data using different species. Two approaches were used to assess the relative response of different marine amphipod species to sediment mixtures. The first approach examined side-by-side data sets from California, i.e. those where sediment toxicity was evaluated using two or more amphipod species (Ampelisca abdita, Eohaustorius estuarius, Rhepoxynius abronius, or Leptocheirus plumulosus). The second approach used large regional sediment quality databases where multiple toxicity test species have been used extensively to compare the relative frequency of response or the incidence of toxicity at the same degree of chemical contamination. Both types of comparisons indicated substantial differences in response among species. For example, side-by-side tests indicated E. estuarius was more responsive to contaminated sediments collected from the California coast than was A. abdita. In Puget Sound sediments, the frequency of observing significant effects at similar magnitudes of sediment contamination was Eohaustorius > Rhepoxynius > Ampelisca. The potential assessment and regulatory implications of the results are discussed.

Key words: sediment toxicity, amphipod, marine, responsiveness