HYDROCHEMISTRY OF SURFACE AND GROUND WATER OF KHULNA DISTRICT, SOUTH WESTERN PART OF BANGLADESH

This study deals with hydro-chemical attributes of surface and groundwater from Khulna District in comparison with standard values for irrigation, industrial uses and drinking purposes. In ground water, pH ranged from 7.02 to 7.43, EC from 0.5 to 5.1 dS m^-1, available Nitrogen from 0 to 69.75 mg l^-1, PO43- from 0.34 to 1.26 ppm, K+ from 3.35 to 11.65 mg.l^-1, SO₄^2- from 0.31 to 3.41 ppm, Ca²⁺ from 142.67 to 208 mg.l^-1, Mg²⁺ from 16.93 to 48 mg.l^-1, TDS from 126 to 5108 mg l^-1, TSS from 166 to 1422 mg l^-1, Na+ from 156.97 to 1007.1 mg.l^-1, Cl- from 106.5 to 887.5 mg l^-1, Boron content from 0.41 to 0.466 ppm, Fe from 0 to 0.08 ppm, no Zinc was detected except Terokhada (0.02 ppm) and Mn content of ground water ranged from 0 to 2.11 ppm. In surface water, pH ranged from 7.17 to 7.75, EC from 0.4 to 2.9 dS m^-1, available Nitrogen from 0 to 31.16 mg l^-1, PO₄^3- from 0.001 to 0.97 ppm, K+ from 8.65 to 30.10 mg.l^-1, SO₄²- from 0.03 to 0.37 ppm, Ca₂+ from 57.33 to 110 mg.l^-1, Mg²⁺ from 8.67 to 47.2 mg.l^-1, TDS from 420 to 2338 mg l^-1, TSS from 106 to 538  mg l^-1, Na+ from 156.97 to 804.53 mg.l^-1, Cl- from 106.5 to 887.5 mg l^-1, Boron content from 0.424 to 0.61 ppm, Fe from 0 to 0.37 ppm, no Zn was detected except Dumuria (1.24 ppm) and Phultala (0.11 ppm) and no Mn was detected except Dhamalia (0.011) and Dumuria (0.02). The pH, Nitrogen, Mg²⁺, Zn, Mn, B, SO₄^2-, Fe concentration were within permissible limit and can be used for all purposes with reference to standards. K⁺, Cl^- toxicity was exhibited in most of the samples of surface and ground water. Salinity of surface water was within the standard concentration for irrigational and industrial uses whereas ground water would require treatment to reduce salinity. Total Dissolved Solids (TDS), PO₄^3-, Ca²⁺ and Na⁺ content of the water were within the permissible limit for irrigation and industrial uses but crossed the limit for use as drinking water. Thus, the water of Khulna District can be recommended for industrial and irrigational uses but having limitations for drinking purposes.