Water quality index analysis in the upstream of Sook river, Sabah, Malaysia.

Rivers are indispensable water resources for human needs such as domestic consumption, agricultural, and industrial purposes. This study aimed to determine the water quality in the upstream of Sook River, district of Keningau, Sabah, Malaysia. The field study was conducted between October 2018 and March 2019, during the wet season due to the Northeast Monsoon. Five water quality sampling stations in the upstream of Sook River area were chosen. And, six quality parameters, namely DO, BOD, COD, pH, NH₃−N, and TSS, were collected to examine the water quality index of the Sook River. The results showed that only the DO parameter was in Class II, indicating that the Sook River was in good condition; COD, pH, and TSS parameters were in Class III (moderately polluted); and BOD and NH₃−N parameters were in Class IV (polluted). Based on the Malaysian WQI, the water quality during the study period was 59 (Class III), indicating a polluted condition. The field observations revealed that the primary sources of pollution in the upstream of Sook River were domestic waste discharge from settlement areas, agricultural activity (oil palm and rubber plantations), and logging near the upstream area. In conclusion, the water quality in the upstream of Sook River is classified as polluted (Class III). Thus, the upstream of Sook River's is unsafe for domestic consumption and must be treated further. Authorities must mitigate efforts to conserve the Sook River's water resources that supply raw water to the Lanas Village water treatment plant for domestic consumption. [ABSTRACT FROM AUTHOR]