Bioconcentration and Toxicity of Dodecylbenzene Sulfonate (C₁₂LAS) to Aquatic Organisms Exposed in Experimental Streams

Abstract

Fish, mollusks, and crustaceans were caged in the tail pool of streams during a C₁₂LAS (dodecyl benzene sulfonate) model ecosystem experimental program. Bioconcentration of total C₁₂LAS and individual isomers and acute and chronic toxicity were investigated during this study. Toxicity endpoints were based on water and tissue (i.e., body burden) concentrations at which adverse effects were observed. At 32 days, total C₁₂LAS bioconcentration factors (BCFs) for the fathead minnow and three invertebrate species ranged from 9 to 116. In general, bioconcentration was affected by isomer position, exposure concentration, and species. BCF values tended to decrease as isomer position moved from external (e.g., 2-phenyl) to internal (e.g., 5,6-phenyl). BCFs also decreased as exposure concentration increased. Mean acute 4-d LC₅₀ values ranged from 1.5 to >3.0 mg/L for the six species tested. Lethal body burdens associated with 50% mortality (LBB₅₀) varied from 0.21 to 0.60 mmole/kg (wet weight). During the 32-day chronic exposures, the EC₂₀ values were 0.27 (0.204–0.352), 0.95 (0.597–1.29), and approximately 1.0 mg/L for Corbicula (length), Hyalella (survival), and fathead minnow (survival), respectively. At these EC₂₀ values, C₁₂LAS body burdens were 0.035, 0.23, and 0.19 mmoles/kg wet weight in Corbicula, Hyalella, and fathead minnow, respectively. Fish exposed to wastewater treatment plant effluent had total C₁₂LAS tissue concentrations ranging from 0.0005 to 0.0039 mmoles/kg wet weight. These concentrations are approximately 45–360 times below the tissue concentration associated with subtle effects in the model ecosystem stream exposures. Total C₁₂LAS body burdens in feral and caged Corbicula exposed to WWTP effluents were approximately 0.0013 mmoles/kg; approximately 25-fold below concentrations associated with effects in stream exposures.