Assessment of water quality and heavy metals in Semenyih River

Abstract

Semenyih River has been considered one of Malaysia’s most important rivers, particularly in the Selangor Region. This river has been the primary water supply for Putrajaya’s domestic and industrial activities in Sepang and Hulu Langat District. However, due to the rapid development near the Semenyih River, this stream’s quality has been heavily affected. Therefore, this research aimed to determine the Water Quality Index (WQI) and heavy metals concentration in the upstream, middle stream, and downstream of the Semenyih River. The upstream is located at Pening River Village, the middle stream situated at Semenyih Town, and downstream located at Buah River Village. The WQI set by the Department of Environmental Malaysia (DOE) has been used to classify Semenyih River. In-situ and laboratory tests were done in quantifying the WQI. Heavy metals concentration such as chromium, iron, manganese, zinc, and lead were tested for the river samples. From the results obtained, all intake points had fallen into Class III, in which extensive treatment is needed for water supply. Meanwhile, for heavy metals, the downstream sample had shown the highest concentration of heavy metals compared to the upstream and middle stream. Thus, the Semenyih River’s rehabilitation is urgently required to reduce the pollution in preserving the water supply in the Selangor region.