河北省平原地区无公害蔬菜产地土壤镉环境安全性预警

Security Early Warning of Cadmium in Non-Environmental Pollution Vegetable Soil in Hebei Plain

通过野外调查采样、室内分析与GIS制图相结合的综合研究方法,对河北省平原地区无公害蔬菜基地未来20年土壤镉的安全性进行预测预警。结果表明:河北省平原地区无公害蔬菜产地土壤中的镉,以大气干湿沉降为最主要的外源输入方式,其贡献率达66.36%。镉元素输出通量中以根菜类蔬菜为最高,叶菜类次之,果菜类蔬菜输出通量最低。通过对区内土壤镉累积量的预测,未来20年河北省平原地区无公害蔬菜基地土壤镉累积含量预测值仍符合现行国标(GB/T 18407.1—2001)要求,但20年后研究区内表层土壤中镉元素含量升幅明显,以每10年高于30%的速度累积,20年后是目前含量的1.6倍,累积量明显增加的区域集中在河北中东部地区,且露地蔬菜种植区土壤镉的净增量是设施蔬菜种植区3.7倍。说明河北省露地蔬菜土壤中由大气干湿沉降输入的镉元素对无公害蔬菜产地构成潜在威胁,需对现行生产加以严格的动态监测管理及污染源头控制,并针对预测含量高的区域进行不同蔬菜种植模式(露地或设施)的区域优化布局。

Security early warning of heavy metal in non-environmental pollution vegetable soil in Hebei Plainfor the coming 20 years was carried out by synthetic research methods of field survey, chemical examination inlab and GIS. The results showed that atmospheric wet and dry deposition were the most important exogenesisinput way of Cd in vegetable soil in Hebei Plain, and its contribution accounted for 66.36%. The sequence ofoutput fluxes of Cd was root vegetables〉 leaf vegetables 〉fruit vegetables. The forecasting data of Cdaccumulation in the non-environmental pollution vegetable soil in Hebei Plain 20 years later would conform tothe national standard（the People＇s Republic of China Safety qualification for agricultural productenvironmental requirements for origin of non- environmental pollution vegetable GB/T 18407.1—2001）, thecontent of Cd in the surface soil 20 years later would be 1.6 times as much as that of present, accumulated by the speed of 30% every decade. Areas with obviously cumulative quantity increase would concentrate in thecentral and eastern regions in Hebei. Moreover, the content of Cd in soil without greenhouse would be 3.7 timesas much as that in greenhouse. To sum up, Cd in soil from atmospheric wet and dry deposition in Hebei Plainwould potentially threaten the non-environmental pollution vegetable areas, therefore we should carry out strictand dynamic monitoring and pollution source control. Furthermore, the regional layout of different vegetableplanting patterns（open field vegetables or greenhouse vegetables） should be optimized according to thecumulative quantity increase.