A preliminary study of element bioconcentration factors within milled rice and wheatmeal in some typical areas of Jiangsu Province

Abstract：On the basis of studying related geochemical data of element distribution in 500 sets of rice seed samples and the cultivated soil and 300 sets of wheat seed samples and the root soil from some typical areas of Jiangsu Province, this paper has reported the bioconcentration factors (BCF) of Cd, Hg, Cu, Pb, Zn, Cr, As, Se, Mo, Mn, Fe, K, Ca and Mg which are distributed in milled rice and wheatmeal. Statistical results show that there exist obvious differences in BCF of different elements：usually BCF of Pb, Cr, Fe etc. is lower than 1%, BCF of Hg, As, Mn, Ca etc. is equal to 1% - 10%, the average BCF of Mo is the largest and the average BCF of Fe is the smallest. It is found that element content exceeds limited-standard in the studied milled rice or wheatmeal samples; for example , Pb content is 15% higher than the limited-standard proportion, and the Cd content is 6% higher than the limited-standard proportion. According to statistical data, there is not direct relationship between BCF distribution differences of related elements and element content exceeding the limited-standard within the above-stated milled rice or wheatmeal samples. Furthermore, it is pointed out that the controlling indicators of BCF distribution include probably soil pH, total organic carbon (TOC), cation exchange capacity (CEC), boron (B) concentration, and so on. There exists obvious negative correlation between the BCF of such elements as Ca and Mg and soil pH, and the correlated coefficient of the BCF of Cd versus soil pH is -0.94 related to the milled rice. The same environmental indicator in soil probably has different effects on BCF of different elements, their correlation can be positive or negative, but all correlations have to be set up with certain condition limits.