Water quality assesment of Pengambang River, Pekanbaru City, Riau Province, Indonesia using pollution index (PI)

Abstract

River water quality monitoring must be carried out because rivers are a source of fresh water for the community. Tributaries in the city of Pekanbaru receive waste from domestic activities, industry, livestock, and agricultural runoff, reducing river water quality. The pollution index is one of the most effective tools for informing river water quality conditions. This research was conducted in one of the tributaries in Pekanbaru City, Indonesia, with a quantitative approach to assess the water quality status of a river using a pollution index. For this research, water samples were collected from three locations upstream, an outlet dam site, and downstream from May to July 2023. The collected samples were analyzed for eight water quality indicators: TSS, pH, DO, BOD, COD, Nitrate, Total Phosphate and Total Coliform. The Pollution Index (PI) method is used to assess the water quality of Pengambang Rivers according to the Indonesian Minister of Environment Decree number 27 of 2021. Guidelines for water quality indicators use class III water quality standards (PPRI 22/2021) for cultivating freshwater fish, livestock, Water for irrigated plants. The water quality of the Pengambang River still meets quality standards (Class III) for the parameters TSS, DO, COD, pH, nitrate, and phosphate, except BOD and total coliform.The PI results show that Pengambang Rivers are categorized as lightly polluted to moderately Polluted with a value of 1.61 to 8.17. The contamination of the Pengambang River was caused by the BOD and Total Coliform values exceeding the water quality standards (BOD = 8.78-17.5 mg/l and T.Coliform ranging from 2600-24,000 MPN/100 ml). The findings indicated that these water bodies were subjected to anthropogenic activities and untreated sewage inflow. Due to the poor quality of the water, these water bodies must be appropriately managed and conservation efforts made.