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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 2174

Guilherme R. Lotufo and John W. Fleeger; Toxicity of sediment-associated pyrene and phenanthrene to Limnodrilus hoffmeisteri (Oligochaeta: Tubificidae). Environmental Toxicology & Chemistry 15(9):1508-1516, 1996

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Acute and sublethal toxicities of sediment-spiked pyrene and phenanthrene to Limnodrilus hoffmeisteri Cleparede were investigated. Phenanthrene was acutely toxic at high sediment concentrations (10-day median lethal concentrations of 297.5 µg g-1; 252.2-348.3, 95% confidence interval [CI]). Pyrene was not acutely toxic, even at concentrations as high as 841 µg g-1. A significant impact of pyrene and phenanthrene on the feeding activity of L. hoffmeisteri was demonstrated through daily collection of egested fecal material during 5- and 10-day experiments. A short (5-day) exposure detected toxic effects more efficiently than a 10-day exposure, yielding IC25 values (estimated concentration causing a 25% reduction of measured endpoint in relation to the control[s]) of 58.9 µg g-1 (32.1-89.4, 95% CI) for pyrene and 28.4 µg g-1 (10.0-41.3, 95% CI) for phenanthrene. Effects on burrowing behavior and reproduction were assessed in a 28-day sediment exposure. Low burrowing avoidance (<25%) was detected in high phenanthrene concentrations (143-612 µg g-1) but was not detected with pyrene. Offspring production was significantly reduced in dosed sediments yielding IC25 values of 59.1 µg g-1 (38.3-112.5, 95% CI) for pyrene and 40.5 µg g-1 (12.1-165.5, 95% CI) for phenanthrene. Decreases in egestion rates in the presence of nonpolar contaminants should be quantified when investigating the effects of bioturbation by deposit feeders on the flux of contaminants from sediments into the water column.