大米重金属污染的健康风险评价

目的：评价某地区大米中重金属对人体健康产生的潜在危害。方法根据是否存在明确污染源，2012年在某市辖区范围内抽取A县、B县和C县产大米34份，对大米中的总砷（As）、镉（Cd）、铬（Cr）、汞（Hg）和铅（Pb）5种重金属进行检测，按照美国国家环境保护署（USEPA）推荐方法，建立大米中重金属污染健康风险评价模型，对重金属通过饮食途径引起的健康风险作出评价。结果34份大米总超标率为52.94％，其中As、Cd、Cr、Hg和Pb污染平均值为0.183、0.115、0.049、0.014和0.247 mg/kg。5种重金属对人体健康危害的年总风险分别为：A污染区7.01×215;10-4 a-1，B污染区5.19×215;10-4 a-1，C污染区6.20×215;10-4 a-1，合计6.12×215;10-4 a-1。结论3地区大米中重金属污染物对人体健康潜在危害的个人年总风险均大于USEPA推荐最大可接受水平（1×215;10-4 a-1）。

A Health Risk Assessment of Heavy Metals in Rice

Objective To assess the health risk of heavy metals in rice from key areas in a city.Methods Based on the distribution of pollution sources,34 rice samples were collected in 2012 from key areas of A county,B county and C county.Five kinds of heavy metals were detected.Health risk associated with the five kinds of heavy metals were assessed using USEPA health risk assessment model.Results The total rate of over standard was 52.9% and the mean concentrations of As,Cd,Cr,Hg and Pb were 0.183 mg/kg,0.115 mg/kg,0.049 mg/kg,0.014 mg/kg and 0.247 mg/kg respectively.The total health risk level was 6.12 ＆#215;10 -4/a and the health risk levels in A,B and C county were 7.01＆#215; 10 -4/a,5.19 ＆#215;10 -4/a and 6.20 ＆#215;10 -4/a respectively.Conclusion The total health risks of three counties are higher than USEPA recommended level （1＆#215;10 -4/a）.