In Dehong prefecture of Yunnan province as example, we are analysis and evaluation the heavy metal index such as Pb, Cd, Hg, As, Cr and Cu in farming soil by the Hakanson potential ecological harm index method. The results shows that the pb between ND-249 mg/kg, the Cd between ND-0�68 mg/kg, the Hg between 0�01-0�55 mg/kg, the As between 0�04-52�18 mg/kg, the Cr between ND-195 mg/kg and the Cu between 0�79-64�3 mg/kg. These 6 element enrichment coefficient ( Cif ) are less than 1, the average of index is Cu>Cr>Pb>Cd>Hg>As, meaning the results belongs to slight pollution. The Potential ecological risk index of single factor ( Eir ) is less than 40, the average of index is Cd>Hg>Cu>As>Pb>Cr, belong to minor ecological risk. The Potential ecological risk index of 7 kinds of soil utilization way ( RI ) is less than 150, the average index is vegetable>rubber>sugarcane>corn>tea>paddy>fruit, the potential ecologic risk level in study area belongs to slight risk, heavy metal element enrichment exist differences due to the different soil utilization, some show moderate pollution phenomenon. Overall, the farmland soil in Dehong prefecture is clean and safety, potential ecological risk is given priority to with Cd and Hg but Pb and Cr has less damaging, the high ecologic risk of soil heavy metal is vegetable utilization.%利用Hakanson潜在生态危害指数法，对云南省德宏州耕作土壤表层重金属Pb、Cd、Hg、As、Cr和Cu进行分析评价。结果表明，德宏州耕地土壤中 Pb、Cd、Hg、As、Cr、Cu含量分别为 ND～249、ND～0�68、0�01～0�55、0�04～52�18、ND～195、0�79～64�3 mg/kg。6种重金属元素富集系数Cif 均小于1，平均值从大到小依次为Cu＞Cd＞Cr＞Pb＞Hg＞As，属于轻微污染；单因子潜在生态风险指数Eir均小于40，平均值从大到小依次为Cd＞Hg＞Cu＞As＞Pb＞Cr，属于轻微生态风险危害；7种土壤利用方式潜在生态危害指数RI均小于150，平均值从大到小依次为菜园＞胶园＞蔗园＞玉米地＞茶园＞稻田＞果园。研究区潜在生态危害水平为轻微危害，不同利用方式重金属元素富集存在差异，局部表现出中度污染现象。总体上，德宏州耕地土壤清洁安全，潜在生态危害以Cd、Hg为主，Pb、Cr危害较小，菜园土壤重金属生态危害风险最高。
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