Influence of season, location, and feeding strategy on bioaccumulation of halogenated organic contaminants in Arctic marine zooplankton

The influence of season, location, feeding strategy, and trophic position on concentration, compositional pattern, and bioaccumulation factors (BAFs) of halogenated organic contaminants (HOCs; polychlorinated biphenyls, chlorinated pesticides, and brominated flame retardants) was investigated within an Arctic zooplankton food web. Water (dissolved fraction) and seven Arctic marine pelagic zooplankton species (including herbivores, omnivores, and predators) were sampled in May, July, and October 2007 at two stations in Kongsfjorden, Svalbard, Norway. The HOC concentrations in both water and zooplankton generally decreased from May to October. The HOC concentrations and patterns among zooplankton species were explained by their feeding strategies, roughly categorized as herbivores, omnivores, and predators, and not stable isotope‐derived trophic position. Field‐derived BAFs varied greatly, with higher BAFs in May compared with July and October. Furthermore, BAFs differed among the species according to their feeding strategies. The relationship between BAFs from the different seasons and KOW (octanol:water partitioning coefficient) showed comparable intercepts and different slopes between May and October, with all relationships diverging from the assumed 1:1 relationship between BAF and KOW. Differences in HOC concentrations and BAFs from herbivores to predators showed that biomagnification occurred in zooplankton. The results suggest that concentrations and patterns of HOCs in zooplankton species are influenced not only by equilibrium partitioning with water but also by feeding strategy. Environ. Toxicol. Chem. 2011;30:77–87. © 2010 SETAC