Study of water quality and water quality status using pollutant index in Sebenaq River, Mahakam Ulu Regency, East Kalimantan

Mahakam Ulu Regency is a regency located in the upper reaches of the Mahakam River. The Mahakam River in Mahakam Ulu Regency consists of several tributaries, one of which is the Sebenaq River, located in the capital city of Mahakam Ulu Regency. The Sebenaq River is used by the local community to meet the need for clean water because PDAM is not yet available and is also used as a means of transportation. The Sebenaq River flows through the central office area of the Mahakam Ulu Regency Government, main roads, and residential areas. Along with the development of Ujoh Bilang Village as the center of the capital city of Mahakam Ulu Regency and the use of Sebenaq River water by the surrounding community, it is deemed necessary to conduct research related to the water quality and quality status of the Sebenaq River. This study aims to provide data on water quality and quality status of the Sebenaq River to be used by related parties in the management and utilization of the Sebenaq River in the future. The locations for water sampling, river cross-section profile data collection, and in-situ parameter testing are Station I (Upstream of Sebenaq River), Station II (Tributary of Sebenaq River), Station III (Sebenaq River Crossing Road 1), Station IV (Sebenaq River Crossing Road 2), and Station V (Downstream of Sebenaq River). Based on the results of the calculation of the determination of water quality status using the Pollutant Index method with class I quality standards according to Government Regulation No. 22 of 2021, the water quality status of the Sebenaq River is classified as lightly polluted, with details of Station I (Upstream of the Sebenaq River) having a score of 3.795 indicating lightly polluted conditions, Station II (Sebenaq River Tributary) with a score of 2.781 indicating lightly polluted conditions, Station III (Sebenaq River Crossing Road 1) with a score of 2.361 indicating lightly polluted conditions, Station IV (Sebenaq River Crossing Road 2) with a score of 2.878 indicating lightly polluted conditions, and Station V (Downstream of the Sebenaq River) with a score of 2.327 indicating lightly polluted conditions.