Analysis And Risk Assessment Of Polychlorinated Biphenyls And Heavy Metals In Fish In Baiyangdian Lake

Polychlorinated biphenyls（PCBs）and heavy metals are common environmental pollutants,which are likely to cause harm to the body through the action of the food chain,so they have attracted widespread attention.Dietary intake is one of the main ways for human exposure to PCBs and heavy metals,especially fish food.Therefore,the detection,analysis and risk assessment of PCBs and heavy metals in fish in Baiyangdian Lake are helpful to understand the status of PCBs and heavy metals pollution in sampling sites,and to provide scientific professional guidance and recommendations for ensuring the health of local residents’diet.A total of 86 samples of 5 fish species were collected in this study.GC-MS/MS and ICP-AES were used to determine the content of PCBs（PCB28,PCB52,PCB101,PCB118,PCB138,PCB153,PCB180）and heavy metals（iron,nickel,zinc,copper,chromium,cadmium and arsenic）in fish.Non-parametric test methods were used to analyze the distribution characteristics of PCBs and heavy metals,the Spearman analyzed correlation factors,principal components and factor were used to judge the source of pollution,and the risk assessment was conducted with reference to the USEPA model.PCBs pollution is widespread in Baiyangdian Lake,with a concentration range of45.48²863.03 pg/g ww,which is far below the maximum limit of aquatic products in China.Compared with fish PCBs studies in other regions,PCBs pollution is a relatively low level.There are differences in the PCBs of the Bao River and Fu River and the pollution sources are different.The content of PCBs in different fish also shows obvious differences,with possible factors including food source,lipid weight,body weight and trophic levels of fish.The composition of PCBs congeners is mainly hexachlorobiphenyl.Low-chlorinated PCBs and high-chlorinated PCBs have similar bioaccumulation patterns in catfish and yellow catfish,but there are different enrichment mechanisms between them.The estimated daily intake(EDI₉₀)based on the population’s highest exposure level ranges from0.134 to 1.238 ng/kg bw/d and the estimated daily uptake(EDU₉₀)is 0.064⁰.429 ng/kg bw/d,which is lower than the tolerable daily intake（TDI）set by World Health Organization.The hazard quotient（THQ）is far less than 1,the maximum allowable intake results(CR_lim)are all greater than 31.23 g/d,and the maximum number of edible times per month(CR_mm)is more than 16 times,which means that PCBs in fish detected by Baiyangdian Lake will not cause potential human carcinogenic risks,and can be eaten with confidence.Cd is not detected at the two sampling sites,and the detection rates of As in the Bao River and Fu River samples are 70.21%and 7.69%,respectively.The distribution trend of heavy metals in the two sites is similar,with the highest Fe concentration and the lowest As concentration.Compared with other regions,the contents of Zn,Cu,and Cd is low,the content of Fe in Baiyangdian Lake is at a general level,the elements of Cr and As are at intermediate levels,and the content of Ni is higher than the domestic levels,lower than the level of foreign researches.The content of heavy metals between different species is closely related and significantly different.The influencing factors of different heavy metal elements are different.Elements such as Fe,Ni,Zn,Cu,and Cr have similar pollution sources,among them,elements such as Fe,Ni,Cr,and Cu may be derived from food.According to location analysis,the sources of heavy metals pollution in Bao River and Fu River are different.There are significant differences in the pollution levels of As in the Bao River and Fu River,and the As in the crucian,catfish and loach samples are heavily polluted.The harm index（HI）is far less than 1,and long-term consumption of these fish will not cause significant non-carcinogenic health risks to humans.The CR_mm of catfish and loach is less than16 times,which indicates that consumption of these two fishes may have a potential risk of As carcinogenesis.Therefore,residents are advised to control the consumption of catfish and loach,and the relevant departments should strengthen the monitoring and management of As element.