Bioaccumulation and Trophic Transfer of Short‑, Medium‑, and Long-Chain-Chlorinated Paraffins in Benthic Biotas of the Haima Cold Seep, South China Sea

The bioaccumulation and trophic transfer of chlorinated paraffins (CPs) in deep-sea environments are vital, but no information is currently available. In the present study, CPs were analyzed in seawater, sediments, and benthic biotas from the Haima cold seeps, South China Sea. Total CP concentrations in biota ranged from 264.7 to 12874.4 ng/g of lipid weight, and their average concentrations, ranked from the highest to lowest, are as follows: sea cucumber ≈ slim tubeworm > crab > brittle star ≈ snail ≈ shrimp ≈ mussel > clam ≈ giant tubeworm. Benthic biotas displayed high accumulation abilities for SCCPs, MCCPs, and LCCPs, exhibiting at least medium-level pollution in the Haima cold seeps. Seawater was considered to be the primary source of CPs for biotas. Higher bioaccumulation potentials occurred in nonchemosymbiotic biotas than in chemosymbiotic biotas. Biomagnification for SCCPs and MCCPs and biodilution for LCCPs were observed between snails and mussels. No trophic transfer patterns were found in the whole benthic biota of the Haima cold seeps. This is the first report of CP bioaccumulation in the deep-sea environment. The results will provide insights into further studying the biological trophodynamics and ecological risks of CPs in deep-sea environments.