| 南方典型产地大米Cd、Zn、Se含量变异及其健康风险探讨 |
| 摘要点击 3011 全文点击 1923 投稿时间：2008-10-13 修订日期：2009-01-17 |
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| 中文关键词 大米 重金属 暴露风险 产地 水稻土 |
| 英文关键词 polished rice heavy metals exposure risk production area paddy soil |
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| 中文摘要 |
| 在我国南方江西、湖南、安徽和广东等典型水稻产区部分市场和污染地区农户随机采取大米样品共70份，分别测定样品中Cd、Zn、Se的含量，并分析不同产地大米的含量差异及其与产地土壤因素的关系，探讨了农民就地消费的食物安全性.结果表明, 70%以上的供试样品Cd含量超出国家食品卫生标准值(0.2 mg·kg-1)，且Cd/Zn（质量比）超出美国学者建议的0.015临界值.所分析的3个元素的样本间变异以Cd为最大，Zn最小.不同产地大米样本间所分析元素的含量及Cd/Zn均呈重金属污染水稻土产地>酸性水稻土产地>中性水稻土产地,且以Cd、Se含量的差异幅度较大，Zn较小.说明土壤Cd化学有效性是影响供试大米Cd含量的主要因素，土壤-水稻系统中Cd迁移与籽粒积累取决于人为污染和土壤的化学性质.分别参照WHO和USEPA 推荐的成人RfD(Cd)值和我国居民平均食物消费结构，分析表明所有供试产地的大米样本对于农民就地消费来说均存在不同程度的潜在Cd暴露风险，以污染土壤产地和酸性红壤性水稻土产地为严重.另外，供试大米样品的 Zn、Se含量普遍偏低, 尚不能满足正常的膳食摄取需要. 因此，南方水稻生产中必须考虑稻米Cd污染对就地消费农民的食物安全风险，控制水稻Cd吸收及高产低Cd育种对于南方水稻生产的可持续发展十分迫切. |
| 英文摘要 |
| In this study, a total of 70 polished rice samples were randomly collected at agro-product markets from some typical regions of South China. Their contents of Cd, Zn and Se were determined by atomic adsorption spectrophotometers (AAS) and atomic fluorescence spectrometry (AFS) respectively. The variation of the contents with rice areas was described in terms of soil conditions and the potential health risk by food exposure to these rice grains for subsistence-diet farmers is discussed. Over 70% of the total samples have Cd contents exceeding the State Food Security Standards (0.2 mg·kg-1) with Cd/Zn ratios exceeding the suggested critical threshold of 0.015. Widest variation was found for Cd and smallest for Zn, showing rice Cd prone to environmental stress. The extent to which the contents of the analyzed elements varied with rice areas was greater for Cd and Se than for Zn, though the contents followed in the same order: polluted area>acid paddy area and neutral paddy area. This further evidenced a determinacy of chemical availability in rice Cd uptake. Taking the reference dose values by WHO and USEPA, the health risk by Cd exposure to the rice diet from different areas was estimated. The consumption of rice from polluted area and acid paddy area may impose serious health risks for subsistence diet farmers though those from neutral paddy area may be still safe under the WHO guideline. It is demanded that the problem of the rice grains high in Cd and low in Zn and Se, and serious potential risk should be taken into account while developing high-yielding rice in acid and polluted rice area of South China. Technology for depressing Cd uptake and low-Cd cultivar breeding should be pursued in rice production sector in the future. |
