Effects of benthic organism Tubifex tubifex on hexachlorocyclohexane isomers transfer and distribution into freshwater sediment.

Shanshan Di, Cheng Cheng, Li Chen, Zhiqiang Zhou, Jinling Diao

Index: Ecotoxicol. Environ. Saf. 126 , 163-9, (2016)

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Abstract

In this study, bioaccumulation and elimination of HCHs in tubifex, and the distribution of HCHs in overlying water and sediment, were studied during a 10-d experiment. A sensitive method was developed for the determination of HCHs in samples based on gas chromatograph (GC) equipped with a nickel-63 electron capture detector (μECD). The limit of detection (LOD) was 0.35 µg/kg for α-HCH and 0.82 µg/kg for β-HCH. Tubifex accumulated HCHs rapidly, and the curves were approximately M-type. The highest level was reached on the 7th day, with 0.34 mg/kg(wwt) for α-HCH and 0.87 mg/kg(wwt) for β-HCH in worms. The AFs of β-HCH in tubifex were higher than those of α-HCH. Moreover, the existence of tubifex significantly reduced β-HCH fluxes from the overlying water to sediment by uptake or degradation and decreased the concentrations of β-HCH in the sediment, but it had little influence on α-HCH fluxes. Moreover, enantioselectivity of α-HCH enantiomers was not observed in tubifex, whether in the bioaccumulation or elimination experiments. At the end of the elimination experiment, approximately 80% and 70% of α-HCH and β-HCH were eliminated, and the depuration half-lives were 4.43 and 5.39 days, respectively.Copyright © 2015 Elsevier Inc. All rights reserved.