Correlation between Selenium and Heavy Metal Content in Camellia oleifera in Hainan, China

Abstract

Eighteen forests of Camellia oleifera in Hainan province, China were selected to measure the contents of selenium (Se), zinc (Zn), mercury (Hg), cadmium (Cd), chromium (Cr), lead (Pd) and arsenic (As) in soils, roots, leaves, and kernels, and analyze the correlation between the soil content and the corresponding content in the plant. It was found that the content of Se in soils ranged between 0.489 and 2.110 mg/kg, and was higher than 1.0 mg/kg in 10 out of 18 forests. The average content of six heavy metals was low and fulfilled the requirements of soil environment for green-food production, except that the contents of Cr, Pb, and Cd exceeded standards in few regions. The content of Se in Camellia oleifera was relatively low. Only five regions showed detectable levels of Se in kernels, with the highest in Fuwen Town of Dingan county of 0.085 mg/kg. The contents of Zn, Cr, Pb, Cd, As, and Hg in roots of Camellia oleifera were higher than in the leaves and kernels. The contents of Zn, Cr, and Pb were higher than that of Cd, As, and Hg. The As content in soil was in significant correlation with that in the roots of Camellia oleifera. The Pd content in the soil was positively correlated with that of the roots of Camellia oleifera. The Cr, Pd and Cd contents in roots were in positive correlation with that in the leaves significantly. However, the Hg content of the roots was positively correlated with that of the kernels. Furthermore, the Se content in roots of Camellia oleifera was negatively associated with that of the other six heavy metals, having a significantly negative correlation between Se and As.