Uncovering Key Pollution Drivers in the Langat River Basin Using Factor Analysis on Water Quality Indicators

Water quality has become a growing concern due to increasing human activities that contribute to river pollution, particularly in rapidly developing regions such as the Langat River Basin. Despite the regular monitoring of individual parameters, a deeper understanding of the interrelationships between water quality indicators remains limited. This study aims to examine the characteristics of water quality indicators and the Water Quality Index (WQI) across the Langat River Basin and to determine the underlying factors influencing the WQI indicators. A total of 360 water quality samples collected between 2020 and 2022 were obtained from the Department of Environment (DOE) Malaysia. Six key indicators which are dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), pH, and ammonia nitrogen (NH3-N) were analysed in this study. Descriptive analysis was conducted to assess the variation of these parameters, while factor analysis was employed to identify pollutant underlying factors. The results revealed two distinct factors explaining over 60% of the total variance. The first factor is linked to organic pollution, while the second reflects physicochemical alterations such as sedimentation and pH disturbance. These findings highlight the potential sources of pollution and offer a simplified structure for interpreting water quality data. This study contributes to the understanding of major water quality drivers in the Langat River Basin and supports more effective environmental assessment, policymaking, and sustainable water resource management.