Cyclic organochlorines in the hermit crabs Pagurus bernhardus and P. pubescens from the North Sea. A comparison between winter and early summer situation

The body burdens of 5 cyclic organochlorine compounds were determined in abdomens of Pagurus bernhardus and P. pubescens from the North Sea during two seasons. The seasonal bioaccumulation of ΣPCB (as the sum of concentrations of 24 individual components) is influenced by the substances associated with food originated from the spring plankton bloom and the resuspended sediments during the winter.The patterns of individual PCB congeners depended on the weight of the abdomens, and the geographical position of sampling. In offshore samples, the findings indicated a relationship between the weight of the abdomen (roughly the age) and the bioconcentration of higher chlorinated biphenyls. The results from the coastal areas demonstrated that the uptake by food determines the steady state concentration of the higher chlorinated congeners in the hermit crab. Pagurus pubescens probably possesses a mixed-function oxygenase (MFO)-system different from that of Pagurus bernhardus because the congeners 2,2′, 3,3′, 4,5,6′-heptachlorobiphenyl (174) and 2,2′, 3,3′, 4′, 5,6-heptachlorobiphenyl (177) were absent in all samples of the former species but were always present in the latter.The geographical differences between concentrations of ΣPCB reflect the general mean-routes of water and suspended particular matter transport through the North Sea: the Southern Bight and the continental coasts were more polluted with PCBs than the central North Sea. Maximum concentrations of p-p′-DDE were found in the southern parts and parts of the central North Sea. Samples from the German Bight showed the highest concentrations of Lindane. The results indicate that the atmospheric transport of lower chlorinated biphenyls, HCB, α-HCH and Lindane may be important in the distribution of these components, because they only showed slight gradients or even none at all in the area investigated.