PT13 Aquatic Ecotoxicology I
Exhibit Hall
8:00 AM - Tuesday

(PT205) Time-dependent toxicity of fluoranthene and pentachlorobenzene to three freshwater invertebrate species.

Schuler, L1, Landrum, P2, Lydy, M1, 1 Southern Illinois University, Carbondale, Illinois, USA2 Great Lakes Environmental Research Laboratory, NOAA, Ann Arbor, Michigan, USA

ABSTRACT- The internal lethal body residue has been recognized as a potential dose metric for toxicological assessments. The time-dependent toxicity of fluoranthene and pentachlorobenzene was investigated for three freshwater invertebrate species (Hyalella azteca, Chironomus tentans, and Diporeia spp.). The lethal body residue required for 50% mortality (LR50) was not constant and decreased with exposure time for all species. Fluoranthene was most toxic to C. tentans having LR50 values of 0.43 mol g-1 at 2 d and 0.17 mol g-1 at 10 d and least toxic to Diporeia spp. having values of 9.97 mol g-1 at 10 d and 3.67 mol g-1 at 28 d. The LR50 values for H. azteca were intermediate with residues ranging from 3.19 mol g-1 at 5 d and 0.86 mol g-1 at 28 d. Pentachlorobenzene LR50 values ranged from 1.20 mol g-1 at 4 d to 0.81 mol g-1 at 10 d for C. tentans, 9.05 mol g-1 at 20 d and 1.81 mol g-1 at 28 d for Diporeia spp., and 1.51 mol g-1 at 4 d and 0.71 mol g-1 at 28 d for H. azteca. When LR50 values for fluoranthene and pentachlorobenzene were compared at steady state, there were no statistical differences between the amphipod species for either chemical, however; C. tentans was more sensitive to fluoranthene than pentachlorobenzene. The influence of lipid content and biotransformation on the LR50 values also will be discussed. The information collected from this study will permit a greater understanding of residue-response relationships in addition to relative species sensitivity.

Key words: time-dependent toxicity, lethal body residue, fluoranthene, pentachlorobenzene

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