Asterias rubens (Linnaeus, 1758), a common sea star in North Sea waters, was selected to study the bioaccumulation of an important polychlorinated biphenyl congener, 14 C-labelled PCB#153, from 2 contrasting sources: seawater and sediments. After 4 wk acclimation to laboratory conditions, sea stars were exposed for 34 d to realistic concentrations (30 ng l -1 in seawater and 9.5 ng g -1 dry wt in sediments) of the contaminant during which time bioaccumulation of PCB#153 was followed in 6 body compartments. The results showed that (1) for each body compartment, PCB uptake kinetics were generally asymptotic and bioaccumulation was far greater when A. rubens was exposed via seawater than via sediments; (2) body wall and podia were the body compartments showing the greatest affinity for the PCB congener, making them ideal tissues for biomonitoring purposes; (3) the concentrations reached in body compartments were within the range of values reported in several field studies. Because radioisotopic techniques are extremely sensitive, they allow key organs that are sometimes too small for standard analysis of PCBs to be taken into account.
KEY WORDS: Polychlorinated biphenyls · PCB#153 · Bioaccumulation · Kinetics · Asterias rubens · EchinodermResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 253: 155-163, 2003, Everaarts et al. 1998. However, to the best of our knowledge, no study has investigated PCB bioaccumulation processes in A. rubens. The only 2 experimental studies investigating PCB bioaccumulation in echinoderms concern sea urchins exposed to contaminated sediments (Weisberg et al. 1996, Schweitzer et al. 2000, and only Weisberg et al. (1996) examined the kinetic aspects of PCB uptake.Such data are however needed to further assess the value of Asterias rubens as a bioindicator of PCB contamination. Therefore, in the present study, we have investigated the kinetics of PCB uptake in A. rubens exposed either to the contaminant in seawater or associated with sediments, i.e. the 2 extreme pathways of contamination from the viewpoint of absolute PCB concentrations. Indeed, the high hydrophobicity of PCBs result in a characteristic partitioning, with concentrations in natural seawater typically in the range of pg to ng l -1 while sediment concentrations are in the range of µg to mg kg -1 (see Table 1). The PCB congener IUPAC #153 (2, 2', 4, 4', 5, 5' hexachlorobiphenyl) was selected because it is the most abundant in marine biota (Stebbing et al. 1992) and has been shown to be an excellent indicator of total PCB contamination (Atuma et al. 1996). (Linnaeus, 1758) were collected in April 1999 from the intertidal zone at Audresselles (Pas-de-Calais, France). Prior to experimentation, specimens were acclimated to laboratory conditions for 1 mo in constantly aerated closed-circuit aquaria (salinity 36 ‰, T 16 ± 0.5 °C, 12/12 h dark/light cycle).
MATERIALS AND METHODS
Sampling. Sea stars Asterias rubensIn order to follow PCB#153 bioaccumulation under realistically ...