耕地土壤重金属污染评价技术研究——以土壤中铅和镉污染为例

在提出将耕地土壤重金属污染评价分为累积性污染评价和农产品产地土壤环境质量适宜性评价两类的基础上,以土壤重金属全量测定值与土壤重金属背景的比值反映土壤累积性污染状况,而以土壤中重金属有效态测定值与土壤中重金属有效态临界值的比值作为评价农产品产地土壤环境质量适宜性的方法,制定了耕地土壤重金属污染监测与评价技术规程,给出了以盆栽试验为基础,小区试验进行验证,以国家食品卫生标准限量值为依据,确定土壤重金属有效态临界值的方法,并将其制定成为耕地土壤重金属临界值技术规范。与目前采用国家《土壤环境质量标准》的评价方法相比,该方法可以更好地反映土壤重金属污染与作物可食部分重金属含量的关系和农产品产地土壤环境质量对种植作物的适宜性。该方法的建立,将为《农产品质量安全法》的实施和我国目前推行的农业标准化生产奠定基础。

The Study of Assessment Technology for Farmland Soil Heavy Metal Pollutions

Two types of farmland soil pollution assessment method were presented in the paper,which were the soil heavy metal accumulation assessment and soil environmental suitability assessment for agricultural producing area.The ratio of detecting value of total soil heavy metal between the soil heavy metal backgrounds was used to reflect the soil accumulation pollution status.The method of suitability assessment technology utilized the ratio of availability of soil heavy metals between the limits of available soil heavy metals.Based on these studies Operational rules for monitoring and assessment of heavy metal pollution of the farmland was constituted.In addition,the standards of detecting methods were also constituted to provide basis for soil environmental suitability assessment.By contrast to the method used environmental quality standard for soils,this method can better reflect the relation between soil pollution and edible parts of crop and the suitability of soil environment to crop.In addition,the assessment results can affectedly on soil environment assessment of agricultural producing area and crop planting.The constitute of these methods provide important basis for "code of primary products quality security "and promotion the standard of agricultural producing.