Concentration trends and bioavailability of chlorinated dioxins to crabs from B.C. pulp mills and harbours
Since 1990 approximately 100 synchronous samples of sediment and Dungeness crab (Cancer magister) hepatopancreas have been collected from B.C. harbours and pulp mill sites and analyzed for chlorinated dibenzo-p-dioxin and dibenzofuran congeners. Mean sediment/crab bioconcentration factors (BSAFs) for both dioxins and furans decrease uniformly from approximately log 0.5 for the tetrachloro congeners to log {minus}2 for the octachloro congeners. Individual pairs of samples vary, but no systematic trends are apparent either over time or between mill sites or depositional environments. Differences in dioxin and furan sources that are apparent as principal components analysis (PCA) class separations in both the sediment and crab data sets also are not reflected in differences in BSAFS. Partial least squares (PLS) path modeling reveals little correspondence in congener patterns between sediments and crabs and rules out a direct pathway for contaminant transfer. Results suggest some food chain bioaccumulation for the tetra and pentachloro congeners, but bioavailability to the crabs decreases from the penta to octachloro congeners, Concentration trends over time for both sediment and crabs from the mill sites suggest that the mill-related dioxin and furans are preferentially associated with a suspended particulate or near-bottom nepheloid fraction that is easily buried over time in quiescent areas (e.g., fjords), but has remained available for accumulation in locations that are well flushed by tidal action.
- OSTI ID:
- 218419
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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