A mass balance model describing multiyear fate of organochlorine compounds in a high Arctic lake.
Data collected over a 3-year study of a high arctic watershed and lake are used to understand the fate of organochlorine compounds (OCs) and form the basis of a mass balance contaminant fate model. The model uses the fugacity/aquivalence approach to describe OC dynamics between air, stream inflows and outflow, the water column, and surficial sediments. The steady-state model results indicate that stream inflows contributed from 96 to >99% of total chemical loadings, but 57-98% of total loadings were lost from the lake via the outlet, the percentage of which is controlled by the hydrologic regime of the high arctic lake. Conversely, only 0.4-3.4% of loadings were retained within the sediments due to the high export rate, minimal scavenging from the water column and low organic carbon fraction of the sediments. Using the unsteady-state model, which includes year-round processes, degradation was estimated to account for losses of 7-32% for the more persistent OCs and 42-50% for the less persistent OCs (alpha-HCH, gamma-HCH, and endosulfan I). If loadings were eliminated, water column concentrations would decline with half-lives <1 year for less persistent OCs and 1-2 years for the more persistent OCs, whereas the half-lives for OCs in sediment are 8-25 years.
Helm
Paul A
PA
Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, Canada.
Diamond
Miriam L
ML
Semkin
Ray
R
Strachan
William M J
WM
Teixeira
Camilla
C
Gregor
Dennis
D
D001110:Arctic Regions; D005544:Forecasting; D019015:Geologic Sediments / Q000737:chemistry; D006207:Half-Life; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000737:chemistry*; D008956:Models, Chemical; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D014874:Water Pollutants, Chemical