CONCENTRATIONS OF POLYCHLORINATED DIBENZO-P-DIOXINS, DIBENZOFURANS AND NON-ORTHO SUBSTITUTED BIPHENYLS IN POLAR BEAR MILK FROM SVALBARD (NORWAY)

Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and non -ortho substituted biphenyls (PCB, CB) were determined in 6 polar bear milk samples from Svalbard (Norway). For these compounds, no data for polar bears have been reported before fi om this region. Most of the PCDD/PCDF congeners were found at detectable levels. Concentrations ex pressed as 2,3,7,8-TCDD equivalents (Nordic model) were in the order o f 1-3 pg/g(-1) fat (0.2-1.6 pg ml(-1) milk) which is comparable with r inged and harp seal blubber from the same region. On whole milk basis, concentrations were similar to those found in human milk. An estimati on of the daily uptake via milk showed that the intake is lower for po lar bears compared to humans. As in human milk, relatively high levels of OCDD were found in some polar bear milk samples. The PCDD/PCDF con gener pattern in the milk was different to that found in polar bear fa t from the Canadian Arctic. Non-ortho substituted PCB levels in polar bear milk were similar to those found in polar bear fat from the Canad ian North. However, CB 77 or 169 dominated in the milk while CB 126 wa s the most abundant congener in fat. PCDD/PCDF levels expressed as 2,3 ,7,8-TE were highly correlated with the fat content of the milk. No co rrelation between CB and PCDD/PCDF concentrations was found Some data indicate that PCDD/PCDF concentrations in polar bear milk decrease wit h increasing time after delivery.