Abstract River and lake basins can be regarded as primary water sources, providing communities with a variety of services, including food supplies, flora and fauna habitats, and household uses. To evaluate the state of the water quality, particularly in the lake basin, sedimentation issues and water quality status are considered. The Kenyir Lake Basin's health was tracked in this study using the Water Quality Index (WQI), JPS River Index (JRI), and Sediment Load (SL) production. Determining and analysing the trends in water quantity and quality throughout the Kenyir Lake Basin was the goal of this study. For the purpose of this study, samples were taken at 21 different locations around the lake basin in the wet (November), dry (September), and normal (July) seasons. Six WQI parameters, four JRI parameters, and three SL production parameters have been chosen. In the linear connection to forecast WQI, JRI, and SL, several important variables serve as inputs. The key parameters were identified for each index, such as pH, Dissolved Oxygen (DO), and ammoniacal nitrogen (NH₃-N) which were critical for the WQI; specific flow was essential for the JRI; and Total Suspended Solids (TSS) were important for the sediment load (SL) production analysis. Furthermore, the Hazard Quotient (HQ) was subsequently calculated to conduct a preliminary assessment of the potential health risks associated with metal exposure. The elements' HQ ingestion values were discovered to be in the following order: Arsenic (As) > Cadmium (Cd) > Copper (Cu) > Cobalt (Co) > Chromium (Cr) > Nickel (Ni) > Zinc (Zn) > Plumbum (Pb); all averaged HQ values were less than 1, suggesting that there was little to no health risk from the metals in question. Overall, the WQI results indicate that the basin's water quality is generally Class I to Class II, with WQI values of at least 60% across all sampling points. Linear relationship analysis identified DO as the most critical parameter influencing the WQI across all seasons (contributing up to 64.40% in the dry season), followed by ammoniacal nitrate (AN) and Biochemical Oxygen Demand (BOD). The human health risk assessment revealed that the non-carcinogenic risk from metal exposure (As, Cd, Cu, Co, Cr, Ni, Zn, Pb) was negligible, as all averaged HQ values were less than 1. However, the carcinogenic risks associated with exposure to As and Cr were identified as high. Although the water quality has not reached a critical threshold, unregulated anthropogenic activities pose a substantial and intensifying threat to the ecosystem and local communities. These findings necessitate a more systematic environmental management approach to mitigate future degradation. Apart from the river, anthropogenic activities such as sand mining, tourism, agriculture, and municipal wastewater treatment were assessed using secondary data obtained from land use records, environmental monitoring reports, and official discharge statistics. Analysis of these data revealed that such activities play a substantial role in contributing to the concentration of polluting elements in the river water. Although the current level of water quality and quantity degradation in the Kenyir Lake Basin has not yet reached a critical threshold, the potential adverse impacts on the ecosystem and local communities are likely to intensify if these anthropogenic pressures remain unregulated.
Kamarudin et al. (Tue,) studied this question.