title: Desorption and bioavailability of spiked pentabromo diphenyl ether and tetrachlorodibenzo(p)dioxin in contaminated sediments.
abstract: The relationship between desorption kinetics and bioavailability of sediment-associated 2,2',4,4,5' pentabromo diphenyl ether [(14)C] (BDE-99) and 2,3,7,8 tetrachlorodibenzo(p)dioxin [(3)H] (TCDD) was examined in the contaminated sediments. The desorption kinetics were measured in a sediment-water suspension using Tenax extraction, and bioaccumulation was examined by exposing Lumbriculus variegatus (Oligochaeta) to BDE-99 and TCDD spiked sediment in a 14-day kinetic study. Both chemicals had a high affinity to the finest particle size fraction (<20 microm) and the large, very slowly desorbing fraction (58-75%). The biota-sediment accumulation factors ranged between 1.9 and 4.4 for BDE-99 and between 1.4 and 2.8 for TCDD. The chemical outflux from the rapidly desorbing fraction and influx into organisms shows the connection between desorption and bioavailability. Despite this, normalization to the rapidly desorbing fraction was unable to reduce differences in bioavailability estimates between the chemicals. Thus, it is evident that chemical extraction in the mixed system (Tenax tubes) does not fully describe the bioavailable fraction that worms face in stagnant sediments in a similar way for all chemicals. However, when all desorbing domains were included in the calculation, the difference between the chemicals disappears. Desorbing fractions were also able to reduce variability in the biota-sediment accumulation factors between the tested sediments when organic carbon-based sediment chemical concentrations were modified by the desorbing fractions.
authors.affiliation: Faculty of Biosciences, University of Joensuu, Joensuu, Finland. arto.sormunen@joensuu.fi
authors.forename: Arto J
authors.initials: AJ
authors.lastname: Sormunen
authors.forename: Matti T
authors.initials: MT
authors.lastname: Leppänen
authors.forename: Jussi V K
authors.initials: JV
authors.lastname: Kukkonen
mesh_terms: D000327:Adsorption; D000818:Animals; D001682:Biological Availability; D004784:Environmental Monitoring / Q000379:methods; D005387:Finland; D005411:Flame Retardants / Q000032:analysis / Q000493:pharmacokinetics*; D019015:Geologic Sediments / Q000737:chemistry*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis / Q000493:pharmacokinetics*; D009835:Oligochaeta / Q000502:physiology; D000072317:Polychlorinated Dibenzodioxins / Q000032:analysis / Q000493:pharmacokinetics*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics*; D018508:Water Purification
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical; C086401:pentabromodiphenyl ether