Taking into account the random and uncertain nature of risk assessment for soil heavy metal contamination, the Monte Carlo technique was introduced for simulating the Hakanson potential ecological risk index. Thus, a stochastic assessment model and an identification method were proposed for the ecological risk assessment of soil heavy metal contamination. As a case study, established models were applied in the evaluation of the degree of contamination and ecological risk of heavy metals(i. e. Cr, Cu, Pb, Zn and As) in crop fields of Zhuangmu town, Hefei City, China. The results showed that the heavy metal Cr ranked as slightly contaminated, while the other four metals, Cu, Pb, Zn and As, ranked as moderate. The corresponding synthetic contamination index, Cd, ranked at a moderate degree with probability of 98. 58% . As for the ecological risk, arsenic was at a moderate risk level, while the other four metals were at a slight risk level. The potential ecological risk index, RI, ranked at a moderate degree with probability of 91. 18%.%基于农田土壤重金属污染风险评估系统的随机性和不确定性,将Monte Carlo模拟技术引入H(a)kanson潜在生态危害指数法中,构建了潜在生态危害指数随机不确定模型,提出了风险等级判别方法,并将其应用于合肥市庄墓镇农田土壤重金属(Cr、Cu、Pb、Zn和As)污染风险的评估.结果表明:除Cr属轻微污染外,农田土壤中Cu、Pb、Zn和As均为中等污染水平,综合污染指数(Cd)属中等污染水平,相应概率为98.58％；除As为中等潜在生态风险外,其他4种重金属均属轻微风险等级,潜在生态危害指数(RI)属中等风险水平,概率为91.18％.
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