| Organochlorine pesticides(OCPs)are a synthetic,broad-spectrum,long-lived chemical insecticide that is a persistent organic pollutant.Although its "primary" emissions are attenuated,the release of OCPs accumulated in the environmental media in permafrost areas,new migration and transformation and environmental distribution will lead to "secondary" emission enhancement.The research shows that the Northeast China is the main pool of environmental OCPs in China,but the OCPs environment in permafrost regions at high latitudes in the North Forest has not been studied in depth.In this paper,the OCPs in soils of permafrost regions in the Daxinganling Mountains in China were studied to study the main OCPs pollutants in the soil.The results were p,p'-DDT,Endosulfan,?-HCH,?-HCH,?-HCH.Endosulfan-II and Endosulfan-I,while the content of other pollutants are all low;the content,composition and distribution of OCPs in soils of permafrost regions in Daxing'an Mountains in China were studied.The contents of soil organic matter and OCPs were also studied.The correlation analysis also analyzed the source of OCPs in the soil of permafrost regions in the high latitudes of Greater Khingan Mountains in China.According to the principal component analysis and the isomer ratios of the detected materials,the sources of pollutants were determined.The total concentration of HCHs in the soil in the study area ranged from 0 to 15703.09 ng.g-1 dw,and the mean value was 572.39 ng.g-1dw.The difference of residual concentration is between0 and 4 orders of magnitude,indicating that there is point source pollution in the study area,while ?-HCH/?-HCH is 0.61,and its ratio is less than 3,indicating that lindane still exists after the HCHs are stopped in use in permafrost regions.For short-term use,?-HCH/?-HCH is 0.56,so the residues of HCHs in the study area are mainly due to historically lower amounts of industrial HCHs and lindane,and the content of ?-HCHin the study area is 37.26.%,the content of ?-HCH is 22.62%,and the ?-HCH is obviously higher,which infers that there is a new lindane input in the area around the study area.The most detected in the study area was p,p'-DDT.Other metabolites of DDTs were not detected,so it was impossible to analyze the DDTs and the detected p,p'-DDT.The Endosulfans concentration range in the soil of the study area has never been detected to 6628.00 ng.g-1 dw with an average of 762.53 ng.g-1dw.Its total concentration is significantly higher than other reported areas in China.The proportion of Endosulfan-I accounts for the proportion.The total amount of 58.6% was higher than that of Endosulfan-II.The ratio of Endosulfan sulfate to 14.68 was lower than that of Endosulfan-I and Endosulfan-II,indicating that a small amount of Endosulfan-II has been degraded into Endosulfan sulfate in the study area.The endosulfan-I/(Endosulfan-I+Endosulfan-II)ratio was compared with the technical composition of endosulfan to determine the endosulfan source region.In this study,the ratio of F?-endo was between 0.61 and 0.78 and the endosulfan was obtained.Comparing the technical components,we can see that the source of endosulfan in the soil in the study area is not due to local use,and there is a new source of endosulfan.The HCB concentration in the study area ranged from 0.01-10.09 ng.g-1 dw,with an average of 1.40 ng.g-1 dw,which was higher than that in other reported areas.The difference between the highest concentration and the lowest concentration was 2orders of magnitude,indicating the existence of point sources.Pollution.The highest content of HCB was in D(forest)followed by grassland G.The residual content of HCB was higher than that of forest sampling point D.Most of the other reported high concentrations of HCB were in cities,indicating that the HCB in the study area existed in its neighboring cities.Sources of pollution are speculated to be related to emissions from the industrial production process around the study area or emissions from the combustion process. |
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