Seasonal impact on water quality and model development of a tropical urban river / Siti Asiah Muhammad

Seasonal climatic variations in Malaysia may contribute to inadequate water supply, unexpected flooding, and river pollution issues.The Penchala River Basin located in Petaling Jaya, Selangor, Malaysia, is noted as being under environmental stress due to several pollution sources, which has amplified the intention to assess the water quality. Therefore, this research aims to study the seasonal impact on water quality and to develop a river model. Four stations from upstream toward downstream were selected along the Penchala River and was monitored from November 2013 until October 2014 on monthly basis. The chemical parameters were analyzed in laboratory guided by the Standard Method. The water quality index (WQI) was calculated using the 6 parameters, namely the Biochemical Oxygen Demand, Chemical Oxygen Demand, Ammoniacal Nitrogen, Total Suspended Solid, Dissolved Oxygen and pH. The result showed physico-chemical parameters have a significant difference between sampling stations (ANOVA, P<0.05) except for pH, turbidity and velocity. WQI classifies Penchala River in Class II (clean) for upstream, Class III (slightly polluted) for middle stream and class IV (polluted) for downstream. The WQI shows better values during wet season compared to dry season by increasing the WQI class from Class IV to Class III at Station 4 during wet season and dragged the WQI class from Class III to Class IV at Station 3 during the dry season. Heavy metals which elements exceeded the limits are Arsenic, Iron and Aluminium. The three elements that have a significant difference between the stations are Manganese, Magnesium and Iron (ANOVA, P