A comparison of organic contaminants in two high Arctic lake ecosystems, Bjornoya (Bear Island), Norway

Lake Ellasjoen and Lake Oyangen are two high Arctic lake ecosystem located on the island Bjornoya (74degrees30' N, 19degrees00' E) in the Barents Sea. High levels of persistent organic pollutants (POPs), especially PCB and p,p'-DDE, were found in sediment and biota from Lake Ellasjoen while levels were several times lower in Lake Oyangen. Stable isotope signatures (delta(15)N) in comparable organisms (e.g. zooplankton, Arctic char) collected from both the lakes were also significantly different. The values of delta(15)N were 6-10parts per thousand higher in the organisms from Ellasjoen than from Oyangen. In both Ellasjoen and Oyangen, a statistically significant correlation (P<0.05) was found between the levels of PCB and DDT, and delta(15)N values in organisms indicating enhanced bioaccumulation for higher trophical level lake organisms. As the lakes on Bjornoya are remote, more than 500 km from any known point source, the presence of POPs is most likely the result of long-range transport of contaminants to the area. The observed higher contaminant concentrations associated with the Ellasjoen ecosystem is attributed to two factors. Ellasjoen is located in the southern, mountainous part of Bjornoya and it is likely that this area receives more precipitation, and thereby more airborne contaminants, than the flatter areas further north on the island (i.e. the area around Oyangen). in addition, higher delta(15)N-levels in organisms from Ellasjoen as compared to Oyangen indicate the input of guano from seabirds using the lake as a resting area as an additional source of POPs to Ellasjoen. (C) 2003 Elsevier Science B.V. All rights reserved.