Distribution Characteristics,Source Analysis And Risk Assessment Of PAHs And OCPs In Polar Regions

Polycyclic aromatic hydrocarbons（PAHs）and organochlorine pesticides（OCPs）,which are typical representatives of persistent organic pollutants（POPs）,are semi-volatile and difficult to degrade.At present,PAHs and OCPs have been detected in the Antarctic and Arctic regions.The Antarctic and Arctic regions play an important role in the process of global climate change and the exchange of materials and energy between the atmosphere and the ocean.The ecosystems in the polar regions are relatively fragile,and pollutants may affect the ecological environment of the polar regions.Cause a serious threat.Therefore,the monitoring and analysis of pollutants in the polar multi-media environment is particularly important.This paper takes soil and biological samples obtained from the thirty-fifth（2019）,thirty-sixth（2020）Antarctic Scientific Research and the tenth（2019）Arctic Scientific Research as the research objects,and 16 kinds of well-controlled PAHs and 10 OCPs pesticides were selected as the research targets,and the distribution characteristics of PAHs and OCPs pollutants in the Antarctic and Arctic research areas were explored.,Sources and ecological risks.The main research results are as follows:（1）In 2019,the average concentration of PAHs in the surface soil of the Antarctic survey region was 9.82 ng·g^-1（dry weight,the same below）,and 15.58 ng·g^-1in 2020;the average concentration of OCPs in the surface soil of the Antarctic survey region in2019 was 2.01 ng·g^-1,0.81 ng·g^-1in 2020,showing a downward trend.During the two years,PAHs were dominated by LMW-PAHs,and showed the spatial distribution characteristics of Adlay Island>Eastern Fields Peninsula>Western Fields Peninsula;OCPs showed the distribution characteristics of Adlay Island>Fields Peninsula.PAHs in the Antarctic survey region are mainly derived from petroleum sources and petroleum combustion sources,and are at low ecological risk;OCPs are mainly derived from atmospheric transmission and historical settlement residues,and will not cause ecological risks.（2）The PAHs in the biological samples of the Antarctic survey region showed a relationship of fish>limpets>krill>dung soil>brown algae>moss,which showed a trend of gradually increasing with the nutritional level.As the trophic level increases,the proportion of HMW-PAHs increases.PAHs in fish head and fish muscle have the rule of big fish>medium fish>small fish.The size of PAHs in different tissues of big fish is:internal organs>fish head>muscle>fish bone.The composition of PAHs in different parts of big fish is slightly different,and the proportion of HMW-PAHs in the viscera is higher than that in other parts.It can be seen that PAHs are more likely to be enriched and amplified in high-trophic organisms.（3）The average concentration of PAHs in the soil in the Arctic survey region was47.38 ng·g^-1,which was higher than that in the Antarctic survey region in the same year;the average OCPs concentration was 2.22 ng·g^-1,which was basically the same as the Antarctic survey region in the same year.The Arctic research area is dominated by LMW-PAHs,the residual level of DDTs is slightly higher than that of HCHs,and the anaerobic environment is dominated.PAHs are mainly derived from petroleum sources and petroleum combustion sources,while OCPs are derived from long-distance atmospheric transmission and historical residues.PAHs are at a low ecological risk,and OCPs will not generate potential ecological risks.