Burden and depth distribution of organochlorine pesticides in the soil profiles of Yangtze River Delta Region, China: Implication for sources and vertical transportation
Burden and depth distribution of organochlorine pesticides in the soil profiles of Yangtze River Delta Region, China: Implication for sources and vertical transportation
复制标题
DOI：
10.1016/j.geoderma.2009.07.016
复制
发表时间：
2009-10
期刊：
影响因子：
6.1
通讯作者：
Haibo Zhang;Yongming Luo;Qingbo Li
中科院分区：
文献类型：
--
作者：
Haibo Zhang;Yongming Luo;Qingbo Li
土壤是其他环境介质和生物有机氯农药的重要来源。六氯环己烷（HCH）、二氯二苯三氯乙烷（DDT）等有机磷农药在长三角地区的农田中大量使用，直到20世纪80年代才被正式禁止用于农业。选取了长三角地区7种主要土壤类型的44个土壤剖面，共收集了169个水平样，对六氯环己烷和滴滴涕进行了分析。棉田滴滴涕残留量最高，为484.24μg/kg d.w.；水田六氯环己烷残留量最高，为17.93μg/kg d.w.。据估计，目前在100cm的土壤深度中，DDT的储存量约为580吨，是六氯环己烷的两倍左右。出乎意料的是，DDT和六氯环己烷的残留量平均分别约有60%和80%埋在15-100cm深度的下伏地层中，对浅层地下水和地下生态系统构成潜在风险。滴滴涕和六氯环己烷组成在水稻土耕层以上的深度分布基本保持不变，表明其向下迁移主要是由生物扰动引起的。而在犁盘下的土层中，更多水溶性化合物的优势表明滴滴涕和六氯环己烷是通过灌溉和降雨淋滤出来的。在旱地和旱地，滴滴涕和六氯环己烷的向下运移机制根据其深度分布表现出站点特异性。
Soil is an important source of organochlorine pesticides (OCPs) to other environmental media and organisms. Large amounts of OCPs, such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), have been intensively applied in the croplands of Yangtze River Delta (YRD) Region before being officially banned from use for agriculture in 1980s, China. Forty-four soil profiles which represent seven major soil types in YRD region were chosen and a total of 169 horizon samples were collected for analysis of HCH and DDT. The highest residual level of DDT (484.24μg/kg d.w.) and HCH (17.93μg/kg d.w.) was detected in cotton field and paddy field, respectively. It is estimated that approximately 580tons of DDT is reserved in the soil depth of 100cm at present, which is around two times higher than that of HCH. Unexpectedly, about 60% and 80% of the residual DDT and HCH on average are buried underlying layers within a depth of 15–100cm respectively, imposing potential risks to shallow groundwater and underground ecosystem. Depth distribution of DDT and HCH compositions is presented fairly constant in the layers above the plough pan of paddy soil, implying that their downward migration is induced by bioturbation principally. While in the layers beneath the plough pan, dominance of more water-soluble compounds infer leaching of DDT and HCH by irrigation and rainfall. In dry land and upland, downward transportation mechanisms of DDT and HCH are shown as site-specific according to their depth distribution.