甘肃省白银市土壤重金属污染地球化学特征及其表生地球化学成因  

Geochemical Characteristics of Heavy Metal's Contamination and Its Surface Geochemical Mechanism in Baiyin City,Gansu Province

作　　者：张祥年[1] 辛存林[2,3] 李春亮[1] 

机构地区：[1]甘肃省地质矿产勘查开发局甘肃省地质调查院,兰州730000 [2]西北师范大学地理与环境科学学院,兰州730070 [3]兰州大学资源环境学院,兰州730000

出　　处：《地质科技情报》2010年第4期124-131,共8页Geological Science and Technology Information

基　　金：中国地质调查局项目"甘肃省兰州-白银地区多目标区域地球化学调查"(GZTR20060112);甘肃省自然科学基金项目(096RJZA116)

摘　　要：基于以土壤为主的多介质地球化学测量,对生态环境问题严重的白银市进行土壤环境质量评价,得出研究区重金属元素在全区呈综合表生富集性污染、中度以上农田生态化学污染及潜在生态风险,重金属元素的表生富集是农田生态化学污染及潜在生态风险的主要原因。污染性重金属元素输入源及污染方式为:白银市区工矿企业、机动车辆产生的废气和烟雾形成的干湿沉降;矿渣及岩矿石水岩反应产生重金属物质的水化学迁移分散;工矿企业污水在渠系径流中的重金属元素沉淀。重金属元素经历氧化还原、水解、络合(螯合)、吸附-解吸、溶胶聚沉等土壤和水化学反应,主要经水化学迁移和大气飘移等空间分散过程,并经沉淀、吸附等表生作用而在区内土壤局部集中形成污染。Based on geochemical survey on soil and other materials, this article undertakes the geochemical assessment of soil environmental quality in Baiyin City suffering from heavy ecological environmental problems. It reveals that the heavy metal elements indicate the whole area is contaminated with compound supergene enrichment of heavy metals against over middle grade of agricultural eco-chemical contamination and potential compound ecological risk. The supergene enrichment of heavy metal elements mainly accounts for the agriculture eco-chemical contamination and potential compound ecological risk. The heavy metal contamination can be mainly attributed to the dry and wet deposition by the vehicle emission and smog from the factories or enterprises of the city, the hydrochemical migration and dissociation by the heavy metal elements produced by the ware-rock reactions of rocks and minerals and heavy metal elements from the sewage. The heavy metal elements in soil and water experience chemical reactions such as oxidization-restoration, hydrolyzing, coordination, absorption-dissociation, precipitation of colloid, and accumulate in partial areas, thus causing serious contamination.

关 键 词：重金属污染 土壤环境质量 潜在生态风险 表生地球化学 白银市 

分 类 号：X142[环境科学与工程—环境科学]