Bioaccumulation of polychlorinated dibenzo-p-dioxins in sediment by oligochaetes: Influence of exposure pathway and contact time
- Univ. of Amsterdam (Netherlands). Dept. of Environmental and Toxicological Chemistry
- Dept. of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.
Oligochaetes (Lumbriculus variegatus) were exposed simultaneously to radiolabeled [{sup 3}H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and [{sup 14}C]octachlorodibenzo-p-dioxin (OCDD) in sediment for 28 d, in order to study accumulation processes of hydrophobic substances. Elimination was studied for a further 20 d. The uptake and elimination rate constants and the bioaccumulation factors (BAFs) were determined for TCDD and OCDD in the presence and absence of sediment (overlying water). Steady-state concentrations in oligochaetes were achieved for TCDD but not for OCDD over the 28-d exposure. Biota-sediment accumulation factors (BSAFs) after a 28-d exposure were 1.6 {+-} 0.27 for TCDD and 0.07 {+-} 0.02 for OCDD. Steady-state log BAF values (lipid based) for TCDD and OCDD in oligochaetes in the overlying water were 5.9 and 5.5 L/kg, respectively. The effect of incubation time between sediment and contaminants was investigated by repeating the accumulation study after a contact period of 21 months. BSAFs of sediment-sorbed TCDD and OCDD were 1.5 to 2-fold lower for the long contact time sediment. Based on comparison of predicted accumulation from pore water and observed accumulation by sediment-exposed oligochaetes, it was concluded that 1.4-fold greater accumulation occurred due to assimilation of TCDD and OCDD from ingested sediment. This additional accumulation in the presence of sediment, not accounted for by uptake only from pore waters, was consistent with literature data for other hydrophobic organochlorines.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 514585
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 16, Issue 7; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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