Levels and trends of toxaphene and chlordane-related pesticides in peregrine falcon eggs from South Greenland

Peregrine falcon eggs were collected in South Greenland between 1986 and 2003 and analysed for 6 congeners of toxaphene and 5 chlordane-related pesticides (cis-chlordane, transchlordane, cis-nonachlor, trans-nonachlor and oxychlordane). Oxychlordane had the highest median concentration of 1448 ng/g lipid weight (lw) or 79 ng/g wet weight (ww) of all compounds. Of the toxaphene congeners, CHB-50 was the predominant congener, with a median concentration of 214 ng/g lw (15.5 ng/g ww). Chlordane-related concentrations were comparable with results from Alaska, but lower than those from the USA, Canada and Norway. Toxaphene did not follow this geographical trend, as concentrations were higher than in Norwegian peregrine falcon eggs. Toxaphene information in birds of prey is limited and comparisons with other species indicate differences in concentrations and organochlorine pattern. Temporal trends showed significant log-linear decreases for cis-chlordane and trans-chlordane, but no significant trends for other chlordanes or the toxaphene congeners, probably affected by the large variation between eggs, also of the same bird. Correlations between chlordanes and toxaphene might suggest similar sources of exposure.