Fate of organochlorine contaminants in arctic and subarctic lakes estimated by mass balance modelling.
Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and subarctic lakes have been hypothesized to be due to processes within food webs and fish physiology. We investigated limnological processes and contaminant chemistry as explanations of these elevated concentrations by developing and applying fugacity-based mass balance models to a relatively small lake in the high arctic and a series of larger lakes in the southern Yukon River basin. The results indicate that high arctic lakes are transient and inefficient sinks for POPs. The mobility of POPs in high arctic lakes is conferred by their hydrologic regime (i.e. partial through flow of melt water loadings) and minimal scavenging and retention in sediments due to extremely low organic carbon in settling and sediment particles. Contaminant dynamics in lakes of the south Yukon River basin are governed by hydrology (i.e., water residence time), because, similarly to high arctic lakes, most of the contaminant inventory resides in the water column due to inefficient scavenging by settling particles. For the less persistent compounds, long water residence time shifts the major loss process from export to degradation. Model results also suggest relatively short degradative half-lives of the hexachlorocyclohexanes (sum of HCHs) and endosulfan, particularly in high arctic Amituk Lake.
Diamond
Miriam L
ML
Environmental Chemistry Research Group, Department of Geography, University of Toronto, 100 St. George St., Toronto, Ontario, Canada M5S 3G3. miriam.diamond@utoronto.ca
Bhavsar
Satyendra P
SP
Helm
Paul A
PA
Stern
Gary A
GA
Alaee
Mehran
M
D000818:Animals; D001110:Arctic Regions; D004785:Environmental Pollutants / Q000032:analysis* / Q000493:pharmacokinetics; D005399:Fishes / Q000502:physiology*; D020387:Food Chain; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000032:analysis / Q000493:pharmacokinetics; D014018:Tissue Distribution
D004785:Environmental Pollutants; D009930:Organic Chemicals