Soil elemental analysis in a high conservation tropical forest in Singapore.

To understand the distribution of soil elemental concentrations and their potential sources of trace metal contamination in the high-conservation Nee Soon freshwater swamp forest in Singapore, we analyzed samples from 227 surface and 35 subsurface (auger profiles) locations. Our assessment involved distribution maps, principle component analysis, cluster analysis, and correlation analysis of element concentrations determined from a mixed acid digestion and measurement on an ICP-MS. We found a distinct zonation in the distribution of several elements (Ba, Cr, Cu, Fe, Mn, Pb, Sr, Ti, V, and Zn) between the upper and lower catchment that gives an erroneous notion of widespread contamination in the lower catchment.