Delineation of PCB uptake pathways in a benthic sea star using a radiolabelled congener

Abstract

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 ...

Bioaccumulation of essential metals (Co, Mn and Zn) in the king scallop Pecten maximus: seawater, food and sediment exposures

“…Sediment grain size distribution was determined using a Mastersizer Micro v2.12 (Malvern) and the dry/wet weight ratio was calculated after freeze drying using a LABCONCO Freezone18. Aerated sediments (9 kg) were divided between two 5-l plastic bottles, spiked with 292 kBq 57 Co, 297 kBq 54 Mn and 306 kBq 65 Zn (half in each bottle) and then constantly agitated for 6 d according to Danis et al (2003Danis et al ( , 2005 and adapted by Metian et al (2007). Part of the radiolabelled sediments were then used to form a homogeneous 4-cm sediment layer in a 20-l glass aquarium.…”

“…Part of the radiolabelled sediments were then used to form a homogeneous 4-cm sediment layer in a 20-l glass aquarium. Weakly-bound radiotracers were allowed to leach from the sediment overnight under flowing seawater (50 l h -1 ) (Danis et al 2003(Danis et al , 2005.…”

PCBs contamination does not alter aerobic metabolism and tolerance to hypoxia of juvenile sole (Solea solea L. 1758)

“…Amongst the POP released in the marine environment, polychlorinated biphenyls (PCBs) are considered as the most toxic and widely distributed class (Abarnou, 2010). In invertebrates seawater constitutes an important exposure pathway (Danis et al, 2003(Danis et al, , 2005) whereas vertebrates accumulate PCBs mainly by the trophic pathways (Boon, 1984;Kelly et al, 2007). Because of their high liposolubility, PCBs easily bioaccumulate in marine organisms and biomagnify along the food chain (Borga et al, 2001;Hoekstra et al, 2003;Nfon et al, 2008).…”

Bioaccumulation and detoxification processes of Hg in the king scallop Pecten maximus: Field and laboratory investigations

“…Hg for 6 d according to the method described in Danis et al (2003Danis et al ( , 2005. They were then used to form a continuous layer of 4-cm height in a 20-l glass aquarium.…”