Population surveys in Greenland 1993-2009: temporal trend of PCBs and pesticides in the general Inuit population by age and urbanisation

The purpose of the study was to analyse temporal trends (1993-2009) of the concentrations of organochlorine contaminants (14 congeners of polychlorinated biphenyls (PCB) and 11 pesticides) in the blood of Greenland Inuit according to age and urbanisation. Statistical determinants for the contaminant concentrations included (for PCB congener 153) age (Δr(2)=0.35), marine diet (Δr(2)=0.10), smoking (Δr(2)=0.02), and sex (Δr(2)=0.01) with comparable results for other organochlorine contaminants. After adjustment for age, diet, smoking, and sex a significant decreasing trend was present for all contaminants ranging from 41% for mirex to 56% for hexachlorobenzene. The temporal trend was most pronounced among participants below the age of 65 years. The decrease started later in villages than in towns. The decrease was present in all age groups and in the capital, other towns, and villages. The decrease is probably due to a combination of reduced concentrations of the contaminants in the wildlife and a slight temporal reduction in the consumption of marine mammals. The significant downwards trend of legacy POPs shows that the legislation works but it must be kept in mind that according to the cumulated scientific evidence there are a multitude of non-regulated persistent organic contaminants in the diet as well as high levels of methylmercury.