摘要
对天门市稻田土壤和稻米中Cd、Hg、Pb等3种重金属元素进行采样监测,参照湖北省水稻土背景值、国家土壤环境质量Ⅱ级标准和国家食品卫生标准进行评价,分析土壤-水稻系统重金属迁移积累特征,并应用US EAP推荐的健康风险评价模型评估当地居民通过土壤-水稻-食物途径重金属暴露所致的健康风险。结果表明,土壤中重金属Cd、Hg、Pb的平均含量低于国家土壤环境质量Ⅱ级标准,但Cd与Hg呈现出明显的累积现象,分别是湖北水稻土对应背景值的1.64和2.17倍。稻米中重金属的平均富集量符合国家食品卫生标准,其富集能力Cd>Hg>Pb;土壤pH值与稻米Cd的富集系数呈负相关、与Hg和Pb呈正相关。健康风险评估结果显示,化学致癌物Cd和非致癌物Hg、Pb的个人年风险值以及个人年总风险值均低于US EAP推荐的可接受风险水平(10-4a-1),对人体所致的健康风险是可接受的。在Cd、Hg、Pb 3种重金属污染物中,化学致癌物Cd的个人年均风险占个人年均总风险的99.94%,是产生健康风险的主要污染物。
Refer to paddy soil background value of Hubei, national soil environmental quality level 1I and standard of food hygiene, the migration and accumulation characteristics of heavy metals in soil - rice system were analyzed through monitoring samples of Cd, Hg, Pb in soil and rice in Tianmen. Meanwhile health risks of heavy metal exposure through soil - rice - food way of local people were assessed with application of health risk evaluation model recommended by US EAP. The results showed that the average contents of Cd, Hg and Pb in soil were lower than the environmental quality standard II of national soil, respectively. While Cd and Hg presented obviously accumulative phenomenon, respectively, they were 1.64 and 2.17 times to background value of paddy soil of Hubei, respectively. The average enrichment quantity of heavy metals in rice accorded with national food hygiene standards with their enrichment capacities as Cd 〉 Hg 〉 Pb, and pH value of soil was negatively correlated with enrichment factor of Cd and positively correlated to that of Hg and Pb. The results of health risk assessment showed that the individual risk value and individual total risk value of chemical carcinogens Cd and non-carcinogens Hg and Pb were lower than that of acceptable risk level （10-4 a-i） recommended by US EAP, respectively. The health risk of human body caused by them were acceptable. In the three heavy metals, individual annual average risk of chemical carcinogens Cd accounted for 99.94% of the individual total annual average risk, which was the major pollutant of health risk. Therefore, it should be the major supervision object of risks.
出处
《土壤通报》
CAS
CSCD
北大核心
2014年第1期221-226,共6页
Chinese Journal of Soil Science
关键词
土壤
大米
重金属
富集系数
健康风险
Soil
Rice
Heavy metal
Enrichment factor
Health risk
