[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 +/- 0.007 mg/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 RfD 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.