BIOACCUMULATION OF LINDANE AND HEXACHLOROBENZENE BY TUBIFICID SLUDGEWORMS (OLIGOCHAETA) UNDER STANDARDIZED LABORATORY CONDITIONS

Lipophilic chemicals released into the aquatic environment tend to ads orb to suspended material and sediments. These compounds are therefore not bioavailable to many pelagic organisms, and their overall bioaccu mulation is often not adequately covered by the currently prescribed m easuring of bioconcentration in fish. The assessment of bioaccumulatio n in sediment-dwelling organisms shall give more detailed information on the hazard of chemicals for aquatic ecosystems. Therefore a standar dised test design is required. The freshwater tubificids Tubifex tubif ex and Limnodrilus hoffmeisteri were chosen as test organisms, while C -14-Lindane (gamma-Hexachlorocyclohexane, gamma-HCH), and C-14-Hexachl orobenzene served as test substances. The bioaccumulation studies were carried out in a static system consisting of artificial sediment and reconstituted water. Uptake as well as depuration phases were examined . Bioaccumulation factors (BAF) were determined from the ratio of conc entration in worm tissue to concentration in sediment, and from the ra tio of uptake rate constant (k(s)) to elimination rate constant (k(e)) , respectively. Lindane concentrations were found to be about 4 times higher in the worms compared to the sediment, HCB was accumulated by a factor of approximately 7. The tubiticid bioaccumulation factors of L indane and HCB are discussed in comparison to corresponding fish bioco ncentration data from literature. The presented data show that the ass essment of bioaccumulation based exclusively on the extrapolation of f ish-BCF to other organisms and environmental compartments is not appro priate. (C) 1997 Elsevier Science Ltd.