Accumulation and transfer of heavy metals in the mangroves from Quanzhou Bay Wetland, SE Coast of China

Abstract

Levels of eight heavy metals in surface sediments and different tissues of Aegiceras corniculatum and Kandelia candel situated in Quanzhou Bay wetland were determined to assess the accumulation and transferability of heavy metals in the mangroves. Acid-extractable concentrations decrease in the sediments as Fe > Mn > Pb > Zn > Cu > Cr > Ni > Co. In both mangrove species, the distribution of metals occurs in the order of root > branch > leaf for Cu, leaf > root > branch for Ni, and root > leaf > branch for the other six metals. Bio-concentration factors of Ni, Cr, Cu, Zn, Fe and Mn are higher than those of Co and Pb in both species. Kandelia candel has a higher ability than Aegiceras corniculatum to accumulate Cu, Ni, Mn, Fe and Co, but weaker for Zn, Cr and Pb. Most of the metals are retained in the roots.