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Long‐term fate and bioavailability of sediment‐associated polychlorinated dibenzo‐ p ‐dioxins in aquatic mesocosms
Author(s) -
Segstro Mark D.,
Muir Derek C.G.,
Servos Mark R.,
Webster G.R. Barrie
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620141021
Subject(s) - environmental chemistry , sediment , benthic zone , water column , environmental science , bioavailability , mussel , bioaccumulation , dreissena , chemistry , ecology , bivalvia , biology , mollusca , paleontology , bioinformatics
The long‐term fate of four polychlorinated dibenzo‐ p ‐dioxin (PCDD) congeners in sediments and their bioavailability to benthic invertebrates were studied in littoral enclosures located in a small lake at the Experimental Lakes Area in northwestern Ontario. The PCDDs sorbed on sediment particles were added to the 5‐m‐diameter enclosures on June 12, 1985, and concentrations in sediment cores (0 to 6 cm) were determined over 1,800‐d (˜ 5 years). Concentrations of 1,3,6,8‐TCDD, 1,3,7,9‐TCDD, HpCDD, and OCDD in the sediment declined, with half‐lives of 4.4±1.7, 4.6±1.9, 6.2±3.1, and 6.0±2.8 year, respectively. Evaluation of the data for 1,3,6,8‐TCDD and OCDD using a sediment‐water exchange model suggested that the decline in PCDD concentrations was due to losses to the water column via diffusion of DOC‐associated PCDDs in pore water and via particle resuspension. After 5 years the PCDDs remained bioavailable to freshwater mussel ( Anodonta grandis ) and crayfish ( Orconectes virilis ) exposed to sediments for up to 78 d. The crayfish had higher mean biota‐sediment accumulation factors (BSAFs) for 1,3,6,8‐TCDD and 1,3,7,9‐TCDD (0.31–0.53) than did mussels (0.07–0.13), whereas BSAFs for HpCDD and OCDD in the two species were similar (0.03–0.09).