Impact of Surrounding Soils on Surface Water Quality in Sembrong River

Abstract

Peatlands enclosed around 2.7 million ha in Peninsular Malaysia, 1.66 million ha in Sarawak, 0.8 million ha in Sabah, and are commonly found in Johor. Previous studies showed that waters in the peat soils area are acidic (pH 5.7 and pH 6.6). Anthropogenic activities such as mining and agriculture, will in turn impact water quality. Agriculture activities, through the usage of fertilizers, produces cadmium and zinc. Furthermore, soils in acidic conditions could liberate aluminum into the river. This study aims to characterize acidified peat soils based on geochemical properties (pH and heavy metals concentrations), identify the impact of the geochemical variability on surface water quality, and determine the effects of hydrologic cycle on the geochemical variability. Sembrong River was chosen as the study site; soils and water samples were collected nearby and from the river. Testing methods for soils and water covered both in-situ measurements and laboratory analyses. All parameters were taken thrice in each of the sampling point (labelled as S1, S2 and S3). The data of precipitation a week before sampling was recorded for early prediction of the water level. Real water level (depth of the river) was measured on the day of sampling. Based on the relation between month and geochemical properties according to water depth, results showed that the properties were affected by the rainfall intensities. Results also revealed the increased the water depth, the decreased the pH value for soil and water. The most acidic for pH value is peat soils with pH 2.52. Besides, the concentration of heavy metals in the surface water for Sembrong River followed the sequence: aluminum > iron > zinc. Overall results of this study have indicated that properties of peat soils, anthropogenic activities and hydrologic cycles have a major impacts on surface water quality of Sembrong River.