Water Quality and Heavy Metals Distribution in Surface Water of the Kelantan River basin of Malaysia

This paper explores the water quality status of the Kelantan River from the middle to lower reaches of the basin, during the dry and wet seasons, in order to provide a scientific reference for protecting local aquatic environments and managing river basin development in the future. Although studies shows that this river basin is fell in Class I under Malaysian National Water Quality Standard in term of heavy metals, the river was overall classified as slightly polluted, based on the Malaysian Department of Environment-Water Quality Index (DOE-WQI), with total suspended solids (up to 291 mg/L) reaching the allowable threshold limit established by DOE. Field data suggests that the decomposition of organic matter could have resulted in lowering the dissolved oxygen levels in the water column. With regards to heavy metals, it was found that they mainly originated from natural sources, but with an increasing level of contribution from anthropogenic activities.