Water Quality Index (WQI) classification of rivers in agriculture and aquaculture catchments

Abstract

Abstract Water quality is always affected by a wide range of human and natural factors which is commonly a result of mismanagement of land, dumping of rubbish and unintentional introduction of chemical material into the river. The rivers in Kuala Selangor and Sabak Bernam districts which lie in active agriculture and aquaculture activities are also not spared from pollution. This study focused on water quality investigation and source of pollution identification in seven rivers in Kuala Selangor and Sabak Bernam. The water quality parameters investigated were Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended Solids (SS), pH and Ammoniacal Nitrogen (AN). Water Quality Index (WQI) was then calculated based on Department of Environmental guidelines. Based on the WQI results, Sungai Selangor and Sungai Tengi were classified as Class III showing slightly polluted, while Sungai Buloh, Sungai Nibong, Sungai Haji Dorani, Sungai Besar (Bagan Cina), Sungai Besar (Parit Timur) and Sungai Bernam were classified as Class IV or polluted. The industrial, residential, agricultural activities in the surrounding area of the rivers that were suspected of being sources of river pollution were also identified.