MP13 Aquatic Ecotoxicology
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(CHU-1117-566958) Sensitivity of the juvenile clam, Mercenaria mercenaria , to Multiple Contaminants.

Chung, K.¹, DeLorenzo, M.¹, Hoguet, J.¹, ¹ NOAA, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, Charleston, SC, USA

ABSTRACT- Littleneck clams (Mercenaria mercenaria) are marine filter-feeding, infaunal mollusks with great commercial importance along the East coast of the US. Previous research in our laboratory has shown that the juvenile clam, Mercenaria mercenaria, is sensitive to a variety of organic (DDT and fluoranthene) and inorganic (cadmium and copper) contaminants in acute bioassays. Aqueous bioassays were conducted to determine the sensitivity of juvenile clams (>212 m and <350 m) to six contemporary-use contaminants (resmethrin, Scourge®, permethrin, imidacloprid, simvastatin, irgarol). The goal of this research was to evaluate the relative sensitivity of this test species to these contaminants. Bioassays were conducted in Revco® Environmental Chambers at 20°C, 20-m filtered seawater (30‰), and a 12-h light:12-h dark cycle. Test chambers consisted of 16-oz glass jars. Mortality was assessed daily. Range finder assays have been conducted on all six contaminants. Juvenile clams showed low sensitivity to the three pyrethroids tested (Scourge®, resmethrin, permethrin). The highest Scourge® concentration of 100g/L elicited only 30% mortality to the clams. The highest resmethrin concentration of 100g/L elicited only 27% mortality to the clams. The highest permethrin concentration of 100g/L elicited only 27% mortality to the clams. Final 96-h LC₅₀ values will be reported for all six contaminants.

Key words: Mercenaria mercenaria, sensitivity, pesticides