Heavy Metals and Major Ionic Pollution Assessment in Waters of Midstream of the River Karatoa in Bangladesh

Abstract

In a quantitative assessment of water collected from the midstream of Karatoa river in Bangladesh, 31 water samples were analyzed to assess heavy metals, major ionic constituents and suitability parameters for irrigation usage. The electrical conductivity of all collected samples were within the range of 450 to 1653 ?S cm^-1 indicating medium to high salinity. Total dissolved solids ranged from 247 to 789 mg L^-1 and the samples were rated as fresh water (<1000 mg L^-1). The anion chemistry in the Karatoa river water was dominated by HCO₃^- and Cl^-, which contributed 66 and 31%, respectively of the total anionic mass balance. On the other hand, the cation chemistry indicated that 8 samples showed dominance sequence as Ca > Mg > Na > K, 8 samples as Ca > K > Na > Mg, 7 samples as Ca > Mg > K > Na, 6 samples as Ca > Na > K > Mg and only 2 samples as Ca > K > Mg > Na. Among the studied heavy metals (Fe, Mn, Cu, Zn, Pb, Cr and Ni), the most dominant metal was Fe and Mn. The concentration of Mn in 13 water samples exceeded the surface water quality standard (0.10 mg L^-1) indicating Mn toxicity. Considering hardness, 6 water samples were graded as moderately hard while the rest 25 samples were graded as hard. As regards to permeability index, 65% of the water samples collected from the midstream of Karatoa river belongs to the unsuitable category.

DOI: http://dx.doi.org/10.3329/jesnr.v5i2.14806

J. Environ. Sci. & Natural Resources, 5(2): 149-160 2012