西安市农业产地环境土壤重金属污染评价

目的]掌握和了解西安市农业产地环境土壤重金属污染状况。方法]对西安市9个涉农区县无公害农产品产地土壤重金属安全现状进行摸底调查,共对609个土壤样品的主要重金属Cd、Hg、As、Pb、Cr进行测定及内梅罗综合指数法评价。结果]灞桥、长安、高陵、蓝田、临潼、阎良污染等级为1级,属于清洁水平;户县、未央和周至污染等级为2级,污染程度为警戒限,污染水平为尚清洁,整体未受到大面积污染,可以作为无公害农产品生产基地甚至可以作为更优质农产品生产基地。但是有极少部分地区重金属含量超过了土壤环境质量标准,在生产区域规划和产地选择时应予以回避或禁止。结论]西安市农业产地环境土壤重金属污染状况整体良好。针对西安市未来的发展规划,提出了可行、科学的建议。

Pollution Evaluation of Soil Heavy Metal Pollution of Agricultural Habitat Environment in Xi’ an City

Objective] To comprehensively grasp the soil heavy metal pollution status of agricultural habitat environment in Xi’an City.Meth-od] Investigation on the safety status of soil heavy metal was carried out in pollution-free agricultural products producing area in 9 districts and counties of Xi’an City.The 5 major heavy metals (Cd, Pb, Cr, As, Hg) in 609 soil samples were detected.And evaluation was carried out by Nemerow index method.Result] Pollution degrees of Baqiao, Chang’ an, Gaoling, Lantian, Lintong and Yanliang belonged to grade one, which were clean level.Pollution degrees of Huxian, Weiyang and Zhouzhi belonged to grade two, which were at warning line.They were gener-ally not at large-area pollution and could be used as the production base of pollution-free agricultural products or high-quality agricultural prod-ucts.However, heavy metal content in very few parts exceeded the environmental quality standard of soil due to the historical reasons of power plant, sewage irrigation and so on.Therefore, these areas should be avoided or prohibited during regional planning and selection of production ar-ea.According to the future development planning of Xi’an City, feasible and scientific suggestions were put forward.Conclusion] Soil heavy metal pollution of agricultural habitat environment in Xi’ an City is generally at good status.