不同水稻品种籽粒Cd、Cu和Se的含量差异及其人类膳食摄取风险

采用田间试验法,研究了江苏省57个水稻品种籽粒对太湖地区乌栅土中Cd、Cu、Se的吸收积累.结果表明水稻籽粒的Cd、Cu、Se含量的变化范围分别为0.099±0.039、4.86±2.595、0.035±0.007mg/kg,指示不同水稻品种对同一土壤中Cd、Cu、Se的吸收及其在籽粒中的积累存在有显著的差异.不同品种籽粒对Cu和Cd的吸收积累有同步的趋势,而高Se品种显示出抑制重金属Cu和Cd积累的倾向.不同品种籽粒中重金属含量的差异可能影响到人类重金属食物摄取的健康风险,57个品种中92%的样品的Cd含量超出USEPA推荐的人类摄取的籽粒临界含量.因此,在土壤重金属污染地区,必须密切注意高Cd、Cu吸收积累品种的大规模栽培.而筛选高Se低Cu、Cd的水稻品种进行品质育种是可能的.

Grain Contents of Cd, Cu and Se by 57 Rice Cultivars and the Risk Significance for Human Dietary Uptake

Field experiment on uptake and accumulation of Cd, Cu and Se in grains by 57 rice cultivars grown on a single Wuzhatu (a black heavy soil) in Jiangsu Province were conducted. The grain concentrations of Cd, Cu and Se varied in the range of 0.099±0.039,4.86±2.595,0.035±0.007mg/kg respectively, demonstrating remarkable inter species difference in heavy metal accumulation in rice grains. Cd uptake and accumulation in grains followed that of Cu by the studied cultivars. However, high Se uptake and accumulation tended to suppress Cu and Cd uptake and accumulation in grains. By calculation using the R_fD values recommended by USEPA and WHO respectively, human health risk was shown to be possible from consuming the rice grains from these varieties by a Chinese diet. The Cd concentration of 92% of the varieties was found over the permissible limit recommended by USEPA. Thus, attention must be paid to extensive cultivation of high Cd accumulation cultivars of rice in polluted rice soils. For grain accumulation of Se was usually associated with low Cu and Cd accumulation, rice breeding with improvement of rice Se level would be possible for production of high quality of rice.