| Perfluoroalkyl substances?PFASs?is a new type of persistent organic synthetic pollutants,because of its good chemical stability,hydrophobic and oleophobic properties,and heat resistance,it is widely used in industrial production and daily necessities.Because these compounds are difficult to degrade under natural conditions,PFASs are widely detected in various environmental media?such as the atmosphere,soil,water bodies and even glaciers in the Arctic?,animal tissues and human blood.Toxicological studies have shown that PFASs have biological toxicity and adverse human health effects,such as immunotoxicity,teratogenicity and endocrine disruption toxicity.Therefore,the contamination status,migration and transformation rules of PFASs in the environment have gained researchers'attention.Lakes?including reservoirs?are important freshwater resources and drinking water sources in China.However,with the rapid economical development,the contamination status of Toxic Chemistry Substances in lake basin is very serious.This problem is particularly prominent in the Northeast and North China regions,which account for a large proportion of China's national economy.Most of the lakes in this region have important drinking water sources and irrigation functions,which are currently subject to different degrees of pollution.However,at present,the data on the pollution of PFASs in lakes in China are still limited,especially the lack of large-scale and systematic survey data.Therefore,in this study,Songhua Lake,Xiaoxingkai Lake,Dahuofang Reservoir in Northeast of China and Yuqiao Reservoir,Guanting Reservoir,Baiyangdian Lake,Hengshui Lake,and Nansi Lake in North China were selected as study areas.The pollution characteristics of PFASs in surface water and sediments of different lakes were analyzed,and the regional differences of distribution characteristics of PFASs in different lakes were discussed.By analyzing the distribution coefficient of PFASs in water-sediment,the distribution behavior of PFASs in water and sediment was explored and discussed to predict the migration and transformation of target compounds in the lake environment.Finally,the risk assessment of PFASs in the surface water and sediments of the lakes was performed.The main research results are as follows:?1?Compared the pollution characteristics of PFASs in surface water samples from three lakes in Northeast China in July 2017 and May 2019,I found that there were fewer types?10types?of PFASs detected in water samples collected in May 2019 than in July 2017?11-12species?,and the overall pollution level of PFASs was slightly higher than that in July2017.But the major pollutants had not changed much,and short-chain PFASs?perfluorobutanoic acid?PFBA?,perfluoropentanoic acid?PFPeA??and Perfluorooctanoic acid?PFOA?were still the predominant compounds.?2?The pollution characteristics of PFASs in the surface water and sediment samples of 8typical lakes in Northeast and North China were analyzed,and the distribution characteristics of PFASs in surface water and sediment were different.The types of PFASs detected in surface water?9-12 species?was more than sediments?5-7 species?.Short-chain PFASs?PFBA,PFPeA,Sodium perfluorohexanesulfonate?PFHxS??and PFOA were the predominant compounds in surface water,while in the sediments,Sodium perfluorooctanesulfonate?PFOS?and PFOA were the predominant PFASs and the detection rate of short-chain PFASs were low.In surface water,the total concentration of PFASs decreased in the order of Baiyangdian Lake(140.47-1828.54?881.88?ng.L-1)>Guanting Reservoir(179.37-415.47?264.82?ng.L-1)>Nansi Lake(17.82-29.17?23.14?ng.L-1)>Xiaoxingkai Lake(9.20-16.54?11.29?ng.L-1)>Hengshui Lake(6.63-17.93?10.33?ng.L-1)>Songhua Lake(3.24-15.86?6.00?ng.L-1)>Dahuofang Reservoir(3.75-5.98?4.76?ng.L-1)>Yuqiao Reservoir(1.42-5.78?2.60?ng.L-1).While in sediment,?PFASs decreased in the order of Baiyangdian Lake(0.48-29.88?9.92?ng.g-1)>Guanting Reservoir(0.67-3.50?1.82?ng.g-1)>Xiaoxingkai Lake(0.58-1.69?1.17?ng.g-1)>Hengshui Lake(0.59-1.29?0.99?ng.g-1)>Yuqiao Reservoir(0.43-1.01?0.65?ng.g-1)?Songhua Lake(0.36-1.07?0.63?ng.g-1)>Nansi Lake(0.22-1.12?0.53?ng.g-1)>Dahuofang Reservoir(0.22-0.65?0.33?ng.g-1).?3?Compared the pollution levels of PFASs in the surface water and sediments of 8typical lakes in Northeast and North China with other domestic lakes,it was found that the pollution levels of PFASs in Baiyangdian and Guanting Reservoir were higher,while the other six lakes were lower.?4?The distribution behavior of PFASs in water-sediment was studied,and it was found that the sediment-water partition coefficient(Koc)of the same compound in different lakes showed a large difference.For PFOA,the order of logKoc in different lakes decreased in the order of Songhua Lake?5.95±1.24?>Yuqiao Reservoir?5.15±0.49?>Xiaoxingkai Lake?4.73±0.69?>Dahuofang Reservoir?4.34±0.41?>Hengshui Lake?3.87±0.56?>Baiyangdian Lake?3.15±1.48??Nansi Lake?3.15±0.70?>Guanting Reservoir?1.24±0.51?.On average,each-CF2 group contributed 0.72 log units to Koc.The logKoc of perfluoroalkane sulfonic acids?PFSAs?with the same carbon chain length was higher than that of perfluoroalkyl carboxylic acids?PFCAs?.?5?Health risks of PFOA and PFOS in the lakes were assessed.The results showed that the RQ of PFOA and PFOS in the surface water and sediments of 8 typical lakes in Northeast and North China were less than 1,which suggested that the PFOA and PFOS contents in the study area may not have adverse effect on the aquatic ecosystem. |
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