Several studies have proved that th

Several studies have proved that there are high concentrations of Zn
in phosphate deposits in fertilizer (Adriano, 1986; Eriksson et al., 1995;
Nan et al., 2002). Correlations of Cd and total potassiumobtained in this
study might be expected on the basis of their common affinity for clay
minerals in sediment (Van der Graaf et al., 2007). Sulfur is a key element
in the biogeochemistry of estuarine soils and sediments (Nobrega et al.,
2013). Rich sulfideswerewidely believed to be themain factors responsible
for the retention of As in mangrove ecosystem with the form of
sulfur–arsenic mixtures (Esther et al., 1997; Liu et al., 2014). Furthermore,
several studies showed that soil organic matter played a fundamental
role in the control of Pb, Cu, Cr and other metals (Calvert et al.,
1985; Lee et al., 1998; McLaren et al., 1983). However, TOC is not a significant
factor contributing to metals in this study. The reason for this