果园土壤有机氯农药残留的时间趋势研究

以天然荒地和蔬菜基地作为对照 ,于 1993年和 2 0 0 3年对北京市某果园中具有不同树龄的老果园和新果园的土壤有机氯农药 (HCH ,DDT)残留情况进行了定位监测 .结果表明 ,在禁用 2 0年后 ,土壤中的有机氯农药残留水平大幅度降低 ,其中老果园的有机氯农药残留浓度显著高于新果园 (P <0 0 5 ) .果园土壤有机氯残留浓度显著高于荒地和蔬菜基地对照 (P <0 0 5 ) .DDT是当地主要的有机氯污染物 ,利用绿色食品生产基地环境质量标准作为评价标准对该果园土壤的污染程度进行了评估 .评估结果表明 ,新果园的土壤质量能够满足绿色食品生产的要求 ,老果园由于土壤中DDT和HCH残留超标严重不适合作为绿色食品生产基地

Temporal trend of organic chlorinated pesticides residues in soils of orchard, Beijing

With barren and vegetable soils as control, in 1993 and 2003, the concentrations of Organic Chlorinated Pesticides (OCPs) were measured in topsoils of a selected orchard in Beijing, which was divided into old and new orchard groups, according to the different cultivation history. The results indicated that OCPs (HCHs and DDTs) degraded greatly in the 20 years after the prohibition of their usage. And the levels of total DDTs and HCHs in the old orchard were significantly higher (P<0.05) than those in the new. Moreover, the residual levels of HCHs and DDTs in the orchard were higher than those in barren and vegetable soils (P<0.05). The pollution potential was assessed on the basis of environmental limits of the greenfood production area in China. New orchard was suitable for the production of greenfood, while old orchard was not suitable, due to relatively higher DDT and HCH pollution.