Spatial Distribution,Bioaccumulation And Trophic Transfer Of Legacy And Alternative Per-and Polyfluoroalkyl Substances In The Beibu Gulf

Legacy per-and polyfluoroalkyl acids(PFASs)have been received global concern over the scientific and public community from this century.The usage of alternative PFASs has been increased due to the restriction and elimination of legacy PFASs.However,the knowledge on pollution,bioaccumulation and trophic magnification of alternative PFASs is poorly understood,especially in subtropical ecosystems.This study investigated the concentrations,partitioning,bioaccumulation,trophic magnification,potential sources and risks of PFAS,including legacy PFASs and alternative PFASs,in surface water and sediments from the subtropical Beibu Gulf,South China.Results are listed below:(1)Concentrations of?PFASs ranged from 0.98 to 2.64 ng/L,0.19 to 0.66ng/g(dry weight dw)and 0.2 to 3.4 ng/g(wet weight ww)in water,sediment and marine organisms from the Beibu Gulf,respectively.Perfluorooctanoic acid(PFOA)was the predominant PFAS(0.16-1.46 ng/L)in water samples,while PFAS in sediment were dominated by perfluorooctanesulfonic acid(PFOS)and PFOA(0.04-0.20 ng/g and 0.04-0.25 ng/g dw,respectively).PFOS was the predominant PFAS(<LOD-1.53 ng/g ww)in the marine organisms,while the concentrations of F-53B(altervative to PFOS,<LOD-0.10 ng/g ww)was about an order of magnitude lower than that of PFOS.(2)Among surveyed environmental parameters(total organic carbon(TOC),grain size,water p H,sediment p H and salinity),TOC and salinity were the dominant factors influencing the sediment-water distribution coefficient(K_d)of PFOA,perfluorodecanoic acid(PFDA),and perfluorononanoic acid(PFNA).Port activities,consumer products and industrial wastewater were recognized as three potential sources of PFASs in the Beibu Gulf.Preliminary environmental risk assessment showed that PFOA and PFOS would not pose risks to the marine aquatic environment.(3)The log BAF values of PFASs detected ranged from 2.02 to 4.21.The greatest log BAF values for PFOS(4.21)and F-53B(3.43)were both found in Johnius fasciatus indicating that PFOS and F-53B were bioaccumulative.There was a significantly positive correlation between log BSAF and the carbon chain length of perfluoroalkyl carboxylic acids(PFCAs).Trophic magnification(TMF)was observed for PFOS and F-53B(TMF>1),while the remaining PFASs were biodiluted through the present food web.The TMF values for most PFASs in the subtropical food webs were lower than those reported in temperate and Arctic food webs.The hazard ratios HR values of PFOS and PFOA in all groups(i.e.fish,shrimps,crabs,and cephalopods)were far less than unity,suggesting overall low PFAS risks for humans through consumption of marine organisms from the Beibu Gulf.This is the first comprehensive survey of legacy and alternative PFASs in a subtropical area of the Beibu Gulf,which provides significant data and theoretical basis to comprehensive understand the transport and fate of PFASs in subtropical marine environment.