Abstract

The pioneer study evaluates water quality status in Nangarparkar area of Thar Desert of Pakistan. Water samples obtained from wells, ponds and storage tanks greatly varied in their chemical composition and nutrient contents. Percentage of hazardous well water samples for irrigation purpose were: pH: 30%; electrical conductivity (EC): 27%; total soluble salts (TSS): 100%; CO₃^–: 70%; HCO₃^–: 27%; Cl^–: 53%; Na⁺: 23%; K⁺: 40%; Ca⁺²: 13%; Mg⁺²: 17%; PO₄^–: 7%; NO₃^–: 100% and for drinking: pH: 30%; EC: 50%; TSS: 100%; CO₃^–: 67%; HCO₃^–: 97%; Cl^–: 100%; Na⁺: 100%; K⁺: 83%; Ca⁺²: 100%; Mg⁺²: 83%; NO₃^–: 0%. Percentages of hazardous pond water samples for drinking purpose are as follows: pH: 20%; EC: 0%; TSS: 100%; CO₃^–: 73%; HCO₃^–: 93%; Cl^–: 100%; Na⁺: 100%; K⁺: 0%; Ca⁺²: 60%; Mg⁺²: 67%; NO₃^–: 40%. Percentages of hazardous storage tank water samples for drinking are expressed as follows: pH: 0%; EC: 0%; TSS: 100%; CO₃^–: 100%;HCO₃^–: 80%; Cl^–: 100%; Na⁺: 100%; K⁺: 0%; Ca⁺²: 100%; Mg⁺²: 80% and NO₃^–: 60%. Storage tanks were more benign than wells and ponds. Nitrates were the dominant contaminant in irrigation water.

Key words:    Water quality, irrigation, drinking, Thar Desert, Nangarparkar, Pakistan.