内蒙古某灌域表层土壤六氯环己烷空间分布特征及影响因素

Distribution Characteristics and Influencing Factors of Hexachlorocyclohexanes in Surface Soil in an Inner Mongolia Irrigation Area

为修复灌区内土壤有机氯农药污染,降低六氯环己烷对土壤环境的危害,对内蒙古某灌域表层土壤进行采样,利用气相色谱测定50个土壤样品中六氯环己烷及其异构体的含量,并利用ArcGIS空间分析技术确定表层土壤中六氯环己烷的分布状况。样本中六氯环己烷的检出率为96%,各样本中六氯环己烷的浓度范围为未检出~23.0 ng/g,平均浓度为4.4 ng/g。4种异构体含量平均值顺序为γ-六氯环己烷>δ-六氯环己烷>β-六氯环己烷>α-六氯环己烷。灌域东北部和西南部残留浓度较高,并由这2个方向向中部地区逐渐递减,表层土壤中的六氯环己烷分布受土壤黏粒量、不同种植种类和灌溉水源的影响较大。虽受人类耕作的影响,但表层土壤中的六氯环己烷污染水平相对较低。

To provide a basis for restoration of soil organochlorine pesticide pollution in the irrigation area and reduce the harm of Hexachlorocyclohexane to the soil environment.In this paper,the surface soil of an Inner Mongolia irrigation area was sample,the amount of Hexachlorocyclohexane and its isomers in 50 soil samples were determined by gas chromatography,and the distribution of Hexachlorocyclohexane in the surface soil was determined using ArcGIS spatial analysis technology.The detection rate of Hexachlorocyclohexane in the samples was 96%,and the concentration of Hexachlorocyclohexane in each sample was between undetected and 23.0 ng/g,with an average concentration of 4.4 ng/g.The order of the average content of the four isomers wasγ-Hexachlorocyclohexane>δ-Hexachlorocyclohexane>β-Hexachlorocyclohexane>α-Hexachlorocyclohexane.The concentration of residues in the northeast and southwest of the irrigated area was relatively high,and gradually decreased from these two directions to the central area.The concentration of Hexachlorocyclohexane in the surface soil was affected by the amount of soil clay,different crop types and irrigation water sources.The impact was relatively large.Although affected by human farming,the pollution level of Hexachlorocyclohexane in the top soil was relatively low.