College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Central South University, Changsha, 410083, China.
Biol Trace Elem Res. 2022 Mar;200(3):1408-1417. doi: 10.1007/s12011-021-02706-1. Epub 2021 Apr 13.
Rice and rice products are the main sources of Cd contamination in humans. The total and bioaccessible concentrations of Cd and three divalent nutrients, Mn, Cu, and Zn, in locally grown rice grains from Hunan and Guangdong Provinces in China were investigated. An in vitro physiologically based extraction test method was introduced to evaluate the bioaccessibility of the target metals in the rice grains. The mean concentrations of Cd in the rice grains were 0.245 mg/kg and 0.235 mg/kg from Hunan and Guangdong Provinces, respectively. Large variations were observed in the Cd concentrations, indicating a heterogeneous distribution of Cd contamination throughout the study areas. The bioaccessibility of Cd, Mn, and Zn in the gastrointestinal fractions was significantly lower than that in the gastric fractions. In contrast, the bioaccessibility of Cu at the intestinal phase was detected in the rice grains from both provinces. The correlation analysis showed significant relationships between total Cd concentrations and bioaccessible Cd fractions, indicating that higher total Cd in rice grains always resulted in higher bioaccessible Cd. Consistent correlations in the rice grains were observed between Zn and Mn. However, a lack of correlation was found between Cd and Zn in the current study. Risk assessment according to bioaccessible Cd would significantly reduce the exposure risk to Cd from rice consumption.
稻米及其制品是人类镉污染的主要来源。本研究调查了中国湖南和广东两省当地种植的稻米中镉和三种二价营养元素（锰、铜和锌）的总量和生物可利用浓度。采用体外生理基础提取试验方法评估了稻米中目标金属的生物可利用性。湖南和广东两省稻米中镉的平均浓度分别为 0.245mg/kg 和 0.235mg/kg。镉浓度存在较大差异，表明研究区域内镉污染呈不均匀分布。胃肠道部分镉、锰和锌的生物可利用性明显低于胃部分。相比之下，两省的稻米在肠道阶段都检测到了铜的生物可利用性。相关性分析表明，总镉浓度与生物可利用镉分数之间存在显著关系，表明稻米中总镉含量越高，生物可利用镉含量也越高。锌和锰在稻米中表现出一致的相关性。然而，本研究中未发现镉与锌之间存在相关性。根据生物可利用镉进行风险评估，将显著降低通过食用稻米摄入镉的暴露风险。
