Spatial Characteristics And Ecological Risk Assessment Of PFASs In Water Around The Coastal Area Of Bohai And Yellow Seas

Perfluoroalkyl substances(PFASs)are a type of persistent organic pollutants with hydrophobic and oleophobic properties,high surface activity,heat resistance,acid resistance and other characteristics,and are widely used in industrial and commercial fields.PFASs have the characteristics of long-distance transmission,environmental durability,and bioaccumulation,and have potential risks to the environment and organisms.As developed countries began to gradually strengthen the control of PFASs,the fluorine chemical industry began to shift from developed countries such as Europe and the United States to developing countries including China.PFASs has been detected in various environmental media,organisms and humans in China,which poses a threat to ecological and environmental safety and human health and safety.In this study,the area around the Bohai and Yellow Seas was selected as the study area,covering 23 cities and 85 rivers in China and South Korea.A total of 126 water samples and 125 sediment samples were collected.The spatial distribution,pollution characteristics,change trends and ecological risk assessment of PFASs were studied.The total concentration of PFASs in the waters around the Bohai and Yellow Seas ranges from 6.75 to 20981.6 ng/L,with a median value of 42.4 ng/L and an average concentration of 413 ng/L.PFOA has the highest contribution rate of 72% in all samples,followed by PFBA,accounting for 9%.The distribution of PFASs is quite different in space in the water body.The highest concentration site is on the Xiaoqing River in Dongying City,followed by several rivers in Laizhou Bay in Weifang City.The concentration of PFASs in the water of China is higher than that of South Korea.The concentrations of PFASs in waters are relatively high in China and PFOA is the predominant pollutant.In contrast,short chain compounds such as PFBA and PFPeA play a major role in water in South Korea.The spatial distribution of PFASs in sediments is similar to that in water samples.The pollution of PFASs in sediments in Dongying,Weifang and Yantai is relatively high,with average values of 11.1 ng/g,3.40 ng/g and 2.33 ng/g,respectively.PFOA is the main compound.The PFASs in the sediments of various cities range from 0.325-11.1 ng/g,with average value of 1.45 ng/g,all at low levels.The largest source of PFASs in the area around the Bohai and Yellow Seas is the discharge of fluorine chemical enterprises,which is the cause of the high concentration of PFASs in the river.The PFASs at the mouth of the Daling River is as high as 469.0 ng/L,and its main sources are the two fluorine chemical plants upstream of it.The PFASs in the Xiaoqing River is 20981.6 ng/L,and the pollution source is also the fluorine chemical enterprises located in the upstream.The concentration of PFASs in Liaodong Bay rivers has shown a stable trend in recent years.The PFASs in the waters of the west coast of South Korea have generally shown a downward trend,while the concentration of PFASs in rivers along the coast of Laizhou Bay has increased significantly.The concentration of PFOA in the Mi river,Jiaolai river,Sha river and Jie river has increased significantly.The concentration of PFASs in the sediments of this area is low,and the exposure of PFOA and PFOS in the sediments has a low risk.The exposure concentration of PFASs in the water body did not reach the values of CMC and CCC,indicating that PFASs in the study area are less harmful to aquatic ecosystems.The concentration of PFOA in some rivers on the south bank of Laizhou Bay exceeds the drinking water standard values set by Europe and the United States,posing a potential health risk to the human body.