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 i n May 1998, in the Northwater Polynya (NOW) to examine persistent organic p ollutants (POPs) in a high Arctic marine zooplankton. Lipid content (dry we ight) doubled, water content (r(2) = 0.88) and delta N-15 (r(2) = 0.54) sig nificantly 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 zooplank ton. The rank and concentrations of POP groups in C hyperboreus over the en tire 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 C IBz (2.42 +/-0.18), although these rankings varied considerably over the su mmer. The alpha- and gamma -HCH and lower chlorinated PCB congeners were th e most common POPs in C. hyperboreus. The relationship between bioconcentra tion factor (BCF) and octanol-water partition coefficient (K-OW) observed f or 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 DD T was observed. After removing the effects of time, the variables lipid con tent, water content, delta N-15 and delta C-13 did not describe POP Concent rations in C. hyperboreus. These results suggest that hydrophobic POP (log K-Ow =3.86.0) concentrations in zooplankton are likely to reflect water con centrations and that POPs do not biomagnify in C. hyperboreus or likely in other small, herbivorous zooplankton. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.