Organochlorine pesticides and enantiomers of chiral pesticides in Arctic Ocean water.
In the summers of 1993 and 1994, seawater samples from the surface layer (40-60 m) were collected to determine the spatial distribution of organochlorine pesticides on expeditions that crossed the Arctic Ocean from the Bering and Chukchi seas to the North Pole, to a station north of Spitsbergen, and then south into the Greenland Sea. Spatial differences in concentration were found that varied with the pesticide. Heptachlor exo-epoxide (a metabolite of heptachlor) and alpha-hexachlorocyclohexane (alpha-HCH) increased from the Chukchi Sea to the pole, and then decreased toward Spitsbergen and Greenland Sea. Chlorinated bornanes (toxaphene) followed a similar trend, but levels were also high near Spitsbergen and in the Greenland Sea. A reverse trend was found for endosulfan, with lower concentrations in the ice-covered regions. Little variation was seen in chlordane concentrations, although the ratio of trans-/cis-chlordane decreased at high latitudes. Several of these pesticides are chiral: alpha-HCH, cis- and trans-chlordane, and heptachlor exo-epoxide. Enantioselective degradation of (-)alpha-HCH was found in the Bering and Chukchi seas, whereas the (+)enantiomer was depleted in the Arctic Ocean and Greenland Sea. Enrichment of (+)heptachlor exo-epoxide was found in all regions. Trans- and cis-chlordane were nearly racemic.
Department of Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, Canada.
L M
LM
Jantunen
T F
TF
Bidleman
D001110:Arctic Regions; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000032:analysis* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis*
D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D014874:Water Pollutants, Chemical