Persistent organic pollutants (POPs) in a small, herbivorous, Arctic marine zooplankton (Calanus hyperboreus):: Trends from April to July and the influence of lipids and trophic transfer

Samples of Calanus hyperboreus, a herbivorous copepod, were collected (n = 20) between April and July 1998, and water samples (n = 6) were collected in May 1998, in the Northwater Polynya (NOW) to examine persistent organic pollutants (POPs) in a high Arctic marine zooplankton. Lipid content (dry weight) doubled, water content (r(2) = 0.88) and delta N-15 (r(2) = 0.54) significantly decreased, and delta C-13 significantly increased (r(2) = 0.30) in the C. hyperboreus over the collection period allowing an examination of the role of these variables in POP dynamics in this small pelagic zooplankton. The rank and concentrations of POP groups in C hyperboreus over the entire sampling was Sigma PCB (30.1 +/-4.03 ng/g, dry weight) > Sigma HCH (11.8 +/-3.23) > Sigma DDT (4.74 +/-0.74), Sigma CHLOR (4.44 +/-1.0) > Sigma CIBz (2.42 +/-0.18), although these rankings varied considerably over the summer. The alpha- and gamma -HCH and lower chlorinated PCB congeners were the most common POPs in C. hyperboreus. The relationship between bioconcentration factor (BCF) and octanol-water partition coefficient (K-OW) observed for the C. hyperboreus was linear and near 1:1 (slope = 0.72) for POPs with a log K-OW between 3 and 6 but curvilinear when hydrophobic POPs (log K-OW > 6) were included. Concentrations of Sigma HCH, Sigma CHLOR and Sigma CIBz increased over the sampling period, but no change in Sigma PCB or Sigma DDT was observed. After removing the effects of time, the variables lipid content, water content, delta N-15 and delta C-13 did not describe POP Concentrations in C. hyperboreus. These results suggest that hydrophobic POP (log K-Ow =3.86.0) concentrations in zooplankton are likely to reflect water concentrations and that POPs do not biomagnify in C. hyperboreus or likely in other small, herbivorous zooplankton. (C) 2001 Elsevier Science Ltd. All rights reserved.