Qualitative analysis and classification of surface water in Bukit Merah Reservoir in Malaysia

An attempt was made to analyze and classify water quality at the Bukit Merah Reservoir (BMR) in Malaysia to determine the degree of pollution and ascertain the required treatment level before usage. Parameters determined included; pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), suspended solids (SS), total nitrogen (TN) and total phosphorus (TP) using both in-situ and standard laboratory procedures. Heavy metal contents such as nickel (Ni), cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), calcium (Ca), iron (Fe) and magnesium (Mg) were also determined using an Inductively Coupled Plasma Mass Spectrometer (ICP MS). Using the water quality index (WQI) tool, all the parameters indicated considerable degrees of pollution with an average classification number of 75.63 in Class III which indicated that the BMR water was slightly polluted. DO ranged between 2.06 and 12.5 mg/L with a mean value of 5.96 mg/L while BOD ranged between 3.08 and 6.32 mg/L with a mean value of 4.6 mg/L, among many other parameters analyzed. Also, the presence of heavy metals was recorded, but did not appear to be much of a threat with the exception of Fe. Most of the pollutants identified were mainly from infrastructural development and agricultural activities. For domestic uses, cleaner water would be required and this would need substantial investment in treatment, while for recreational, livestock and crop irrigation purposes, the water quality would be acceptable at the present level.