Trace metals, grain size and organic matter in sediment from a coastal area of Thailand and Malaysia

The sediment of Pattani Bay in Thailand and the Setiu Wetlands in Malaysia was investigated in the dry and wet seasons of 2014 to evaluate levels of trace metal concentrations (As, Cd, Cu, Pb, and Zn), sediment grain size, and organic matter. The mean concentrations of all the elements in both seasons (dry and wet) at Pattani Bay were higher than those in the Seitu Wetlands. High levels of As were detected in both seasons, but they were classified as moderately polluted in the dry season. The Enrichment Factor in relation to aluminum showed significant (Enrichment Factor >5 in the wet season) anthropogenic activity as related input for As in both areas and for Pb at Pattani Bay. Surprisingly, the metal concentrations (As, Cu, Pb, and Zn) were only significantly (p < 0.01, p < 0.05) correlated with clay content in the dry season at Pattani Bay. Silt-clay content and the amount of organic matter at Pattani Bay were higher than those of the Setiu Wetlands.