Repas lama dam water quality and heavy metal contamination using Qual2k

Repas Lama Dam in Bentong Pahang has been experiencing pollution by Non-Point Sources (NPS) that can be found upstream of the Sungai Repas, the pollution being so evident that discoloration of the water is observable at the location. The area is littered with mines active and inactive, with many of the inactive mines being improperly shut down. When there are mining activities, some major waste or tailings are produced as the by-products of the process which drastically increases the amount of pollution that a water body that runs through these areas will contain. The Water Quality Parameters at a location, whether biological, chemical, or physical, can give a lot of insight into the level of pollution found in a water body. Through collecting these parameters and running them through a water quality model, it can give a lot of information on the present state of a river and help in attaining predictions of the health of a river. QUAL2K is the water quality model that was used to analyse the water at Old Repas Dam and further make predictions on the state of the river after 10 years. After the modelling process, the water quality parameters and the heavy metals present were analyzed using the Malaysian National Water Quality Standard (NWQS), which also assisted in classifying the water at Old Repas Dam based off individual parameters and its overall Water Quality Index score. The major water quality parameters that were used for this study are Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Ammonia Nitrogen, pH and Total Suspended Solids (TSS). In terms of heavy metal analysis, the heavy metals that were looked at are Arsenic (As), Lead (Pb), Zinc (Zn), Copper (Cu), Tin (Sn) and Aluminium (Al). The data for these parameters being collected from studies that were conducted on the site in 2021 and information given by the Department of Statistics Malaysia.