Indication of geographic variaritions of organochlorine concentrations in the blubber of Antarctic Weddell seals (Leptonychotes weddelli).
A sample cleanup procedure using microwave-assisted extraction (MAE) with focus open vessel (FOV-MAE) technique was validated for the determination of organohalogen compounds in the blubber of a Weddell seal (Leptonychotes Weddelli) from the Antarctic (King George Island, 62 degrees 14' S, 58 degrees 40' W). Good reproducibility in replicate analysis of samples confirms the suitability of the method for samples with very low persistent organic pollutant (POP) concentrations. The method was used to analyze three additional blubber samples of Weddell seals from King George Island. This community of Weddell seals showed the lowest DDT (11-19 microg/kg) and PCB (1-2.5 microg/kg) concentrations so far detected in comparable marine mammals from all over the world. The concentrations determined in the four Weddell seals were also typical for the population at King George Island. However, the DDT and PCB concentrations on King George Island were one order of magnitude lower than in samples of the same species from other sites in the Antarctic (located between 69 degrees S and 78 degrees S). This suggests a wide variability of organohalogen levels in the Antarctic, depending on the geographic site. King George Island (62 degrees S) is found at the outskirts of the Antarctic Peninsula, i.e., the region with the mildest climate in the Antarctic. Low organohalogen levels at this site were attributed to a lower degree of condensation in comparison with locations further south. Most of the reference samples were taken in the Weddell and Ross Seas, i.e., from coastlines as close as possible to the pole. Consequently, other sites on the same latitude as the Weddell and Ross Seas are found on the Antarctic continent This raises the question whether high proportions of organohalogens are being deposited on the Antarctic continent where they are not available to marine organisms. Although this hypothesis has to be proven in follow-up studies, our study clearly demonstrates that it is complicated, if not impossible, to derive time trends in concentrations of POPs in biota from different reference sites in the Antarctic.
Vetter
Walter
W
Institute of Food Chemistry, University of Hohenheim, Garbenstrasse 28, D-70599 Stuttgart, Germany. w-vetter@uni-hohenheim.de
Weichbrodt
Marion
M
Stoll
Elke
E
D000273:Adipose Tissue; D000818:Animals; D000864:Antarctic Regions; D003634:DDT / Q000493:pharmacokinetics*; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000493:pharmacokinetics*; D005843:Geography; D007306:Insecticides / Q000493:pharmacokinetics*; D011078:Polychlorinated Biphenyls / Q000493:pharmacokinetics*; D046048:Seals, Earless; D014018:Tissue Distribution
D004785:Environmental Pollutants; D007306:Insecticides; D003634:DDT; D011078:Polychlorinated Biphenyls