From soil to rice - a typical study of transfer and bioaccumulation of heavy metals in China

For the purpose of studying the contamination, bioaccumulation and transfer of heavy metals and understanding the effects of soil properties on these, the work was carried out on a regional scale. A total of 30 sets of soil and pairing rice tissues samples (root, straw and grain) were collected in Xiangzhou of Guangxi, China; soil properties and Cd, Cu, Pb and Zn of different rice tissues were analyzed. The mobility and bioaccumulation of Cd, Cu, Pb and Zn were assessed by transfer coefficients and bioaccumulation factors of them. The results indicated that the excess proportions of Cd and Pb were 50%, 3.33% and 30%, 6.67% in soil and rice grain, respectively, according to Chinese maximum permitted concentrations of heavy metals. Cd and Zn showed stronger bioaccumulation and mobility capability; the bioaccumulation and transfer of Cu were slightly lower than Cd and Zn; Pb had the weakest mobility. The bioaccumulation and mobility of heavy metals from soil to rice were restrained by soil pH, CaO, SOC, Fe oxides and Mn.