Legacy and emergent persistent organic pollutants (POPs) in NW Mediterranean deep-sea organisms

The levels and profiles of organochlorine (OC) contaminants, including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and penta- (PeCB) and hexachlorobenzene (HCB), as well as polybrominated diphenyl ethers (PBDEs) were determined in muscle samples of the deep-sea fish Alepocephalus rostratus, Coelorinchus mediterraneus and Lepidion lepidion and the red-shrimp Aristeus antennatus from the NW Mediterranean Sea. Mean PCB and DDT levels ranged from the highest concentrations in the fish A. rostratus (Σ(7)PCBs 6.93±0.71 ng/g w.w. and ΣDDTs 8.43±1.10 ng/g w.w.) to the lowest concentrations in the crustacean A. antennatus (Σ(7)PCBs 1.17±0.24 ng/g w.w. and ΣDDTs 2.53±0.26 ng/g w.w.). The concentrations of ΣHCHs and HCB were more than one order of magnitude lower, ranging from 0.07-0.36 ng/g w.w. and 0.03-0.15 ng/g w.w., respectively, while PeCB was only detected in a few samples. PBDE levels were approximately ten times lower than PCB and DDT concentrations, ranging from 0.47±0.20 ng/g w.w. in A. antennatus to 0.92±0.13 ng/g w.w. in A. rostratus. The high-molecular-weight PCBs 153, 138 and 180 represented 69-79% of Σ(7)PCBs in fish and 60% in the red shrimp. Moreover, in fish, the main DDT compound detected was the metabolite p,p'-DDE (70-80% of ΣDDTs), indicative of old DDT residues. In contrast, o,p'-DDE was the main DDT metabolite (49% of ΣDDTs) in shrimp, while the parent compound p,p'-DDT and its metabolite p,p'-DDE exhibited similar proportions of 16% and 21%, respectively. For PBDEs, the most abundant congeners were BDEs 28, 47, 99, 100 and 154 in fish (>70% Σ(14)PBDEs), while BDEs 153 and 209 were also important in A. antennatus, suggesting different uptake and/or biotransformation rates of PBDEs between fish and crustacea. In this sense, the ratios BDE 99/100, BDE 153/154, and BDE 47/99 were determined as proxies for BDE metabolization capacities and contrasted among species.