Pony Testing International Group, Beijing, 100095, China.
Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China.
Environ Sci Pollut Res Int. 2020 Apr;27(12):13205-13214. doi: 10.1007/s11356-020-07790-9. Epub 2020 Feb 3.
Arsenic (As) and mercury (Hg) are toxic elements that are often classified as heavy metals, much like cadmium (Cd) and lead (Pb) and others. In this study, we determined the As and Hg contents in rice samples obtained from commercially available rice in Beijing and the health risks associated with daily dietary exposure to As and Hg by the consumption of this rice. Furthermore, the pollution levels of the rice were evaluated based on the Nemerow index. For this purpose, we collected 353 rice samples from 16 municipal districts in Beijing and determined the As and Hg contents in these samples by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS). The results were as follows: (i) the average content of As in the collected rice samples was 154.91 μg/kg (95% confidence interval (CI) of 139.90-169.92 μg/kg), and the average content of Hg was 2.02 μg/kg (95% CI of 1.25-2.79 μg/kg), which did not exceed the limits established by China's National Standard; (ii) the Nemerow index indicated that the As and Hg contents in these rice samples were safe; (iii) the dietary exposure to As and Hg by rice consumption was, respectively, 15.35 μg/day and 0.20 μg/day, which accounted for 12.91% and 3.35% of the total dietary exposure, respectively; (iv) the hazard quotients (HQs) of As and Hg by the dietary consumption of rice were, respectively, 0.77 and 0.03, and both the HQ and hazard index (HI is 0.8) were less than one. These results indicate that dietary exposure to As and Hg would have no detrimental effect on the health of the residents in the study area; however, the possible carcinogenesis by As in these residents warrants serious attention.
砷（As）和汞（Hg）是有毒元素，通常被归类为重金属，与镉（Cd）和铅（Pb）等元素类似。在这项研究中，我们测定了从北京市市售大米中采集的大米样本中的 As 和 Hg 含量，并通过食用这些大米来评估每日膳食暴露于 As 和 Hg 所带来的健康风险。此外，我们还基于内梅罗指数（Nemerow index）评估了大米的污染水平。为此，我们从北京市 16 个市辖区采集了 353 份大米样本，通过微波消解和电感耦合等离子体质谱法（ICP-MS）测定了这些样本中的 As 和 Hg 含量。结果如下：（i）采集的大米样本中 As 的平均含量为 154.91μg/kg（95%置信区间（CI）为 139.90-169.92μg/kg），Hg 的平均含量为 2.02μg/kg（95%CI 为 1.25-2.79μg/kg），均未超过中国国家标准规定的限值；（ii）内梅罗指数表明这些大米样本中 As 和 Hg 的含量是安全的；（iii）通过食用大米摄入的 As 和 Hg 分别为 15.35μg/天和 0.20μg/天，分别占总膳食摄入量的 12.91%和 3.35%；（iv）通过食用大米摄入的 As 和 Hg 的危害商数（HQ）分别为 0.77 和 0.03，HQ 和危害指数（HI 为 0.8）均小于 1。这些结果表明，通过食用大米摄入的 As 和 Hg 不会对研究地区居民的健康造成不良影响；然而，这些居民体内 As 可能具有致癌性，需要引起高度关注。
