为探索有机氯农药在扩散迁移、水-土界面作用等表生地球化学过程中的组成变化规律,对经济作物基地有机氯农药研究发现:土壤和水介质中17种有机氯农药均有检出,主要污染物为HCHs、DDTs和硫丹硫酸盐。土壤中有机氯农药含量(3.47~544.22ng/g)远高于水体中有机氯农药含量(2.55~4.06ng/L),水体中有机氯农药有随深度而降低的趋势。通过等值线图描述HCHs和DDTs在土壤表层(0~5cm)和土壤下层(5~20cm)中的空间分布,反映了人类使用农药的历史。统计分析显示有机氯农药组分间的相关性较强(相关系数R为0.63~0.84(P〈0.01,N=23)),这与农药来源相对稳定(即主要是早期使用残留)有关。
To study the law of composition and change of organic chlorine pesticides (OCPs) during geochemistry process of transfer between water and soil surface action, concentrations of 17 OCPs were determined in soil-water medium from the base area for economic vegetation in Xiangfan City, Hubei Province, with dominant pollutants as HCHs, DDTs and Endosulfan sulfate. OCPs residues in soil ranged from 3.47 to 544.22ng/g surpassed approximately an order magnitude than those ranged from 2.55 to 4.06ng/L in water, with concentration of OCPs in shallow subsurface (0-5cm depth) higher than those in deep soil layers (5-20cm depth). Spatial distribution of HCHs and DDTs from soil reflected the known historical usage of these pesticides. Strong positive correlation among components of OCPs from soil can be found, and factors affecting residue levels and compositions of DDT and HCH from soil and water were also discussed.