Study on Water Quality at Manjung River and its Tributaries

A study on the water quality has been carried out at selected sites within the river of Manjung and its tributaries. The research is to determine the quality level and classification of 6 sampling station at the Manjung River based on Water Quality Index (WQI), National Water Quality Standards (NWQS) and Environmental Quality Act (EQA). Six (6) point sources were selected for water sampling along the rivers for analysis to identify concentration of pollutant from diffused sources. Water samples taken were subjected to physical, chemical and biological water quality analyses. The physical, chemical and biological water quality analysis had been carried out in accordance to the American Public Health Association (APHA) testing procedures. The study focuses on the analysis of twelve (12) parameters including Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Ammoniacal Nitrogen (NH3-N), Fecal Coliform, Oil & Grease, Turbidity, Conductivity, Salinity, Temperature and pH. The results shows that the river has low level DO (range 3.20-4.03 mg/L) and high level of COD (range 170.83-420.83 mg/L). Oil and grease shows the concentration in range 2-5 ppm which is in limits Standard B (<10ppm) by following EQA. Feacal coliform presented in class III (<5000MPN) according to NWQS. Based on WQI, water quality at Manjung River fall under class III and indicated as moderate at upstream and downstream. While, classified class IV as slightly polluted at middle of stream. Comparison with previous study by Department of Environment (DOE), in Annual Report 2010 shows that at least 23.9% was decreased water quality at Manjung River. Rapid expansion and increasing important of industrial and aquaculture activities along Manjung River, due attention should be paid to mitigate or remedy the impact of excessive effluent in order to safeguard our future environment.