Elemental concentration in a potentially protected forest catchment in Singapore

A total of 24 soil samples, including 4 subsurface, 34 water samples and 17 sets of hydrological survey data were collected in a soil investigation and hydrological survey campaign from August 2017 to September 2018 at a small Dermawan forest catchment, Singapore. The study was to understand and evaluate the catchment's soil and stream status through the assessment of elemental concentrations and their possible sources. Dermawan catchment exhibited a distinct neutral environment in both soil and stream water, with remarkably high concentration of Ca, Mg and Ba in both matrices. Most elements in Dermawan forest have higher concentration than those from other forested catchments in Singapore though we believe that they occur naturally, mainly due to the close proximity between the catchment's soil and stream. These elements most likely derived from the underlying Gombak Norite geology (for soil) and indigenous soil (for stream water). Despite that the catchment is in natural status, localized anthropogenic disturbance to the catchment is obvious given the enrichment of various metals. Therefore, further investigations and management attention are needed given the sensitive nature of hill stream in the Dermawan forest, which is recognized as one of the rare and important habitats in Singapore for biodiversity conservation.