Long-term fate and bioavailability of sediment-associated polychlorinated dibenzo-p-dioxins in aquatic mesocosms
- Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Soil Science
- Freshwater Institute, Manitoba (Canada). Dept. of Fisheries and Oceans
- Great Lakes Lab. for Fisheries and Aquatic Sciences, Burlington, Ontario (Canada). Dept. of Fisheries and Oceans
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 north-western 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 ({approximately}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).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 118648
- Journal Information:
- Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 10 Vol. 14; ISSN 0730-7268; ISSN ETOCDK
- Country of Publication:
- United States
- Language:
- English
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