Influence of Sediment on Anthracene Uptake, Depuration, and Biotransformation by the Amphipod Hyalella azteca

Abstract

Uptake, depuration, and biotransformation rates of anthracene were determined for Hyalella azteca (Amphipoda, Crustacea) in both the presence and the absence of sediment. The mean rate constant ± SE for uptake from water was the same for cases with or without sediment, 255 ± 76 mL∙(g animal wet weight)⁻¹∙h⁻¹. The rate constant for uptake of sediment-associated anthracene was 19 ± 5 g dry sediment∙(g animal wet weight)⁻¹∙h⁻¹ for an organic sediment. Depuration increased by a factor of three in the presence of sediment. Sediment-associated anthracene, compound sorbed to sediment and in pore water, was estimated to contribute 77% of the steady-state body burden. These animals, and presumably other benthic organisms exposed to toxicants in organic sediments, are at higher risk than animals not associated with sediments. Further, bioconcentration factors based on the ratio of body burden to water concentration are overestimates for H. azteca and other benthic organisms that obtain a large proportion of their body burden from sediment.Key words: anthracene, Hyalella azteca, sediment, PAH