包头工业区周边耕地砷和镉环境地球化学特征研究

耕地中重金属含量超标直接影响农作物和灌溉水的质量，而且严重影响人体健康.通过调查内蒙古包头工业区周边灌溉水、化肥、农作物及根系土中砷和镉含量及形态特征，研究其转化和富集规律，结果表明，区内土壤和灌溉水呈偏碱性，灌溉水和化肥中砷、镉含量符合国家标准;玉米、向日葵、甘蓝、葱的根系土和可食部分砷含量均未超标，砷主要以残渣态形式存在;4种农作物根系土中镉有不同程度超标现象，向日葵籽粒镉含量超标50%，其余作物可食部分镉含量均未超标.通过分析发现，向日葵籽粒镉超标的原因是与镉赋存形态主要为碳酸盐态和腐殖酸态及向日葵籽粒对镉的富集高于其他植物有关.

ENVIRONMENTAL GEOCHEMISTRY OF ARSENIC AND CADMIUM IN CULTIVATED LAND AROUND BAOTOU INDUSTRIAL ZONE

Excessive heavy metals in cultivated land directly affects the quality of crops and irrigation water, and therefore human health. By investigating the contents and phase states of arsenic and cadmium in irrigation water, chemical fertilizers, crops and root soil around Baotou industrial zone in Inner Mongolia, the paper studies the transformation and enrichment rules of As and Cd. The results show that the soil and irrigation water are weakly alkaline, and the contents of As and Cd in irrigation water and fertilizer are in accordance with national standards. The As contents in root soil and edible parts of corn, sunflower, cabbage and green onion are all below the limit by official standards, mainly existed in the form of residual state. The Cd contents in the root soil of the four crops above exceed the standard in different degrees. Except for 50% exceeding of Cd in sunflower seeds, the edible parts of other crops are below limit. It is found that the excessive Cd in sunflower seeds is because Cd is mainly occurred in carbonate and humic acid forms and the enrichment of Cd in sunflower seeds is higher than that in other plants.