南方花生产区镉污染综合治理策略

Development strategies for integrated management of cadmium contamination in peanut in South China

近年来,土壤和农产品重金属污染问题已经引起了全社会广泛关注。我国建立了农用地分类管理制度,按照土壤污染程度,将农用地划分为优先保护类、安全利用类和严格管控类,鼓励对严格管控类农用地采取调整种植结构等风险管控措施,但目前尚缺乏科学有效、可大面积推广应用的种植结构调整模式。花生是我国重要的食用植物油来源和休闲食品,对土壤中镉等重金属的富集能力较强,同时由于镉在花生仁中大部分与蛋白质结合,花生油中的镉含量非常低,花生油食用安全风险极低。在我国南方重金属污染耕地定向发展油用型花生生产,既能缓解食用油缺口,提升油料有效供给,又能解决目前严格管控类耕地轮作休耕模式和种植结构调整的可持续性问题。鉴于南方产区油用和食用花生差异化的需求,提出了在未污染的旱坡地大力发展食用花生、在轻中度和重度镉污染区分别发展花生-水稻、花生-油菜轮作模式等南方花生生产布局建议,以及加强花生多元化育种和加快产地土壤污染风险管控技术研发、分别制定食用花生与油用花生的重金属限量标准、加强市场监管和花生重金属含量监测、培植区域花生油加工企业等保障质量安全的产业发展政策建议。

In recent years,heavy metal contamination in soil and agricultural products has aroused widespread concerns.China has established a classified management system for agricultural land.According to the soil contami⁃nation degree,agricultural land is divided into 3 categories,priority protected,safe use and strict control.The adop⁃tion of risk control measures is encouraged,such as adjusting the planting structure of strictly controlled agricultural lands.But scientific and effective mode of planting structure adjustment is still needed for wide application.Peanut is an important source of edible vegetable oil and leisure food in China,with strong ability to accumulate cadmium(Cd)and other heavy metals in soil.Since Cd is mostly bound to protein in peanut kernel,Cd content in peanut oil is low enough for food,thus the directional development of oil peanut in heavy metal contaminated land in southern China might not only alleviate edible oil shortage and improve oil supply,but also solve the sustainability problem of crop rotation and planting structure of the limited cultivated land at present.For the differentiated demand of oil and edible peanut,suggestions were put forward on peanut distribution in South China including developing edible peanut in unpolluted upland sloping field,developing peanut-rice and peanut-rape rotation patterns in the areas with mild,moderate and severe Cd pollutions,respectively.Policy suggestions included diversifing peanut breeding and accelerating research and development of soil pollution risk control technology,establishing limit standards of heavy metals for edible peanut and oil peanut respectively,strengthening market supervision and monitoring of heavy metal content in peanut,and cultivating regional peanut oil processing enterprises.