晋江流域表层土壤中有机氯农药分布特征及污染评价

Distribution and pollution assessment of organochlorine pesticides in surface soils from the Jinjiang River Basin in Fujian,China

以网格法(12km×12km)采集晋江流域42个表层土壤代表性样品,并用GC-ECD内标法对土壤中的滴滴涕(DDTs)和六六六(HCHs)进行分析,揭示了研究区土壤中有机氯农药(OCPs)的残留水平、空间分布及来源.结果表明,晋江流域土壤中HCHs及DDTs的异构体或衍生物的检出率在81.0%～100%之间.OCPs、HCHs和DDTs含量范围(平均值)分别为3.98～114.69ng.g-1(平均值22.38ng.g-1)、1.16～30.13ng.g-1(平均值3.73ng.g-1)和1.42～111.93ng.g-1(平均值18.65ng.g-1).对不同土地种植类型的比较结果表明,土壤中HCHs平均含量排序为:蔬菜地>水稻田>茶树地,DDTs平均含量排序为:茶树地>蔬菜地>水稻田.同时,蔬菜地中HCHs的使用具有非均一性,而由于水稻与蔬菜的交替种植,二者的DDTs来源具有同一性.通过污染评价分析发现,晋江流域土壤整体处于我国一级标准范围内,但与荷兰标准相比,研究区土壤有机氯农药污染存在一定的生态风险,应引起重视.

Surface soil samples were collected and analyzed for HCHs and DDTs from the Jinjiang River Basin in Fujian,China.The concentrations of OCPs in the 42 samples were detected by GC-ECD using the internal standard method.The detectable ratios of HCHs and DDTs were in the range of 81.0%~100%.The OCPs concentrations in soils of the Jinjiang River Basin were in the ranges of 3.98~114.69 ng·g-1（mean：22.38 ng·g-1）,HCHs 1.16~30.13 ng·g-1（mean：3.73 ng·g-1） and DDTs 1.42~111.93 ng·g-1（mean：18.65 ng·g-1）.The order of HCHs in different land uses was：vegetable land paddy field tea land,and the order of DDTs was：tea land vegetable land paddy field.The results also indicated that the distribution of HCHs in the vegetable land was obviously varied,and DDTs in vegetable land and paddy field were attributed by the similar sources.According to the standard of GB15618—95,the pollution burden in soil of Jinjiang River Basin was ＂Grade I＂.However,comparing with the soil standard of the Netherlands,surface soils of Jinjiang River Basin posed a higher risk to humans.