Assessment of water quality for drinking/irrigation purpose from Mangla dam, Pakistan

Abstract

Mangla dam is one of the largest water reservoirs used for irrigation/drinking purposes and power production in Pakistan. The present study is the assessment of physicochemical parameters and selected metals in surface water samples collected from Mangla dam to evaluate water quality for irrigation and drinking purpose. The concentration of selected metals (Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) was determined by flame atomic absorption spectrophotometer. Average levels of the metals showed the decreasing concentration order: Ca > Mg > Na > K > Pb > Fe > Cr > Ni> Cd > Zn > Mn > Cu. Multivariate statistical methods evidenced significant anthropogenic contributions of Cd, Cr, Ni and Pb in water samples from the reservoir, which were above the permissible levels. The measured levels of pH, TA, EC, TDS, Cl – , PS, KR, Mg/Ca, MAR and PI were within the permissible limits. Based on the TH, the water samples were graded as moderately hard, while HCO 3 – and RSBC demonstrated that the water samples were categorized as unsuitable for irrigation use. However, the irrigation water quality (IWQ) index revealed medium level suitability of the water for agricultural use. The study revealed elevated concentration of Cd, Cr, Ni and Pb and suggested that future planning and management strategies should address the metal contamination for restoration of water quality of the reservoir.