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(P321) Bioavailability and desorption of sediment spiked flame retardant and PAH.
Sormunen, Arto*,1, Leppänen, Matti1, Kukkonen, Jussi1, 1 University of Joensuu, Joensuu, Finland
ABSTRACT- The effects of temperature and aging on the bioaccumulation and desorption of sediment spiked 14C-labelled 2,2′,4,4′-tetrabrominated diphenylether (TBDE) and benzo[a]pyrene (BaP) was examined. Lumbriculus variegatus (Oligochaeta) was exposed to recently spiked (2 weeks) and aged (2 years) sediment in a kinetic study for 10 d at 10°C and 20°C. Desorption was measured in sediment–water suspension using Tenax® extraction. Higher temperature and shorter contact time increased worm uptake rates and correspondingly rapidly desorption fractions and rates. Biota-sediment-accumulation-factors (BSAFs) ranged between 2.3 and 4.1 for TBDE and 0.5 and 1.0 for BaP when total OC based sediment chemical concentrations were used. Correcting sediment concentrations with rapidly desorbing fraction (actual suggested bioavailable fraction) resulted much higher BSAFs: 8.9-18.9 for TBDE and 4.4-17.5 for BaP and hence failed to explain observed differences. This variation could not be explained by temperature or aging effect either. Processes governing bioaccumulation in sediment may be more complicated than expected. For example, uptake can be very local and kinetically limited microscale process in which case animal activity (burrowing and feeding) may result different bioavailable pool that cannot be explained only by rapidly desorbing fraction and chemical concentration in pore water.
Key words: TBDE, BaP, Bioaccumulation, Desorption
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