a The Key Laboratory of Food Safety Risk Assessment , Ministry of Health, China National Center of Food Safety and Risk Assessment , Beijing , China.
Food Addit Contam Part B Surveill. 2014;7(2):141-6. doi: 10.1080/19393210.2013.860485. Epub 2014 Jan 10.
Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg(-1). The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg(-1) and 1.5 to 25.4 μg kg(-1), respectively, with a mean level of 3.4 μg kg(-1) and 4.9 μg kg(-1), respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg(-1) Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg(-1) bw week(-1)), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09-0.19 μg kg(-1) bw week(-1) and 0.14-0.27 μg kg(-1) bw week(-1), respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2-4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.
对中国 15 个主要稻米产区的 440 对精米和糙米样品中的总汞（THg）水平进行了测量，并评估了不同年龄段中国人群通过食用大米摄入 THg 的相关健康风险。采用直接测汞仪测量 THg 含量，检出限（LOD）为 1.5μg/kg。精米和糙米样品的 THg 含量范围分别为未检出到 17.8μg/kg和 1.5 到 25.4μg/kg，平均值分别为 3.4μg/kg 和 4.9μg/kg。除了三个糙米样品的浓度高于谷物规定的限量值（20μg/kg Hg）外，所有精米和糙米样品的 THg 水平均较低。根据 THg 含量和相应的大米摄入量估算了不同年龄段人群的 THg 摄入量，并通过食品添加剂联合专家委员会（JECFA）制定的暂定每周耐受摄入量（PTWI）（5.0μg/kg bw 周(-1)）评估了相关健康风险。不同年龄段人群通过食用精米和糙米摄入 THg 的第 50 个百分位数分别为 0.09-0.19μg/kg bw 周(-1)和 0.14-0.27μg/kg bw 周(-1)，均远低于 PTWI，表明相关健康风险较低。然而，2-4 岁儿童的 THg 摄入量第 99.9 个百分位数达到了 PTWI（精米）的 20.6%和 PTWI（糙米）的 29.5%，值得关注。
