烟台市土壤有机氯农药分布及迁移规律

OCPs Distribution in Soil and Their Migration Rules in Yantai City,Shandong

通过对山东省烟台市生态地球化学资料的系统整理,研究土壤持久性有机污染现状与分布迁移规律。结果表明,小麦和水样中没有检出HCH、DDT及衍生物,相对1980年降幅最大,说明在小麦种植区较好地执行了禁用HCH、DDT的政策;土壤中仍检出有HCH、DDT及衍生物,DDT及其衍生物检出样品占样品总数的34.59%,HCH及其异构体检出占土壤样品总数的0.015%;表层土壤中HCH残留量由70年代的0.282μg/g降至0.151μg/g,相差近2倍;DDT由0.3872μg/g降至0.346μg/g。DDT残留物主要集中在表层土壤中,20～40cm的土层中残留量已明显降低,40～60cm的土层中残留量未检出,揭示了有机氯农药的水溶性很差,容易被土壤颗粒所吸附,在土壤环境中的移动性很弱,因而难以向深层土壤迁移的规律。同时表层土壤中约有612km2控制面积内(p,p′-DDE+p,p′-DDD)/p,p′-DDT的比值小于1,说明可能存在新的DDT污染源输入,土壤持久性有机污染成为烟台生态环境质量问题之一,为土地污染防治提供了科学依据。

Yantai City is one of the core cities of the Shandong Peninsula blue economic zone.We have studied soil persistent organic pollution status and distribution-migration rules,based on eco-geochemistry data.The results of the study showed that in wheat and water samples no HCH,DDT and derivatives were detected,and their contentions now have dropped more seriously than those in 1980,which gives an explanation that in the wheat growing areas the policy prohibition of use of HCHs and DDTs has been well implemented.HCHs and DDTs are still detected in 399 soil samples.DDTs account for 5% of the total soil sample,while HCHs account for 0.015%.From the 1970s to now,the contentions of HCHs in soil are 0.282 μg/g to 0.151 μg/g,and DDTs are 0.3872 μg/g,dropping to 0.346 μg/g,DDT residues are mainly concentrated in the surface soil,20 to 40 cm of residues in soil has been reduced significantly,and DDTs are not detected in 40 to 60 cm depth of soil,which reveals the organic chlorine pesticides are less water-soluble,so they are easy to be absorbed on soil particles in the environment of soil,and their adsorption mobility is very weak,so they are hard to move downwards to deep soils.There may be a new input of DDTs in Yantai City.So persistent OCP pollution has become one of the eco-environment quality problems threatening soils of Yantai City.Meanwhile,this study provides a scientific basis for land pollution prevention.