ABSTRACT

A study was conducted to assess the surface water quality of Gournadi Upazila for using irrigation, drinking, and livestock consumption. Twenty samples were collected and prepared for analysis in the Department of Agricultural Chemistry, Patuakhali Science and Technology University (PSTU). The chemical analyses included pH, EC, TDS, Ca, Mg, K, Na, S, and P. The pH indicated that surface water samples were neutral to alkaline in nature and were suitable for irrigation, drinking, and livestock consumption (pH value 6.7-8.10 in surface water). On the basis of EC, all the samples were found to be non-saline (EC value 0.18-0.50mS/). The concentration of Ca, Mg, Na, P, S, and K for surface water ranged from 10.16-23.0, 4.87-45.42, 301.10-703.41, 0.52-1.96, 4.66-44.28 and 3.15-16.98 mg/L, respectively. The surface waters were rated suitable for irrigation, drinking, and livestock consumption on the basis of Ca, Mg, Na, and P, S, and K concentrations.

Key words: Drinking, irrigation, water quality, surface water

Introduction

Water is the most valuable and vital resource for the sustenance of life and also for any developmental activity (Kumar et al, 2010). About 80% of the earth’s surface is covered with water. Out of the estimated 1,011 million km3 of the total water present on the earth, only 33,400 m3 of water is available for drinking, agriculture, domestic and industrial consumption (Dara, 2007). Bangladesh is a low-lying flat country with big inland water bodies, including some of the biggest rivers in the world, and is extremely vulnerable because of its geographical characteristics (Matin and Kamal, 2010). Water quality is deteriorating day by day due to biological, physical, and chemical variables. The primary causes of the deterioration of surface water quality are the decomposition of municipal, domestic, industrial, and agricultural wastes (Todd, 1980). It is also contaminated by mixing with rains and floods which wash down some agrochemicals into rivers, canals, and ponds. If these elements exceed the acceptable limit, it becomes harmful to fish cultivation. However, the water toxicity varied from season to season. In most cases, macro and micronutrients were higher in the winter season than those during the monsoon season (Mitra and Gupta, 1999). The main soluble constituents of water are Ca, Mg, Na, and sometimes K as cations and Cl, SO4, HCO3, and sometimes CO3 as anions. However, ions of some other elements such as Li, Si, Br, I, Cu, Ni, Co, F,B, Zr, Ti, V, Ba, Ru, Ce, As, Bi, Sb, Be, Cr, Mn, Pb, Mo, Se and P and organic matter are present in minor quantities (Michael, 1997). Quality water is necessary for every type of use, but the quality of natural water is judged by its total salt concentration, a relevant proportion of cations and anions, the concentration of toxic substances like As, Cd, Cr, Pb, Hg, Co, Cu, Mn, Fe, Mo, B, etc. It can be said that any element present in water above the international limit for specific use may be treated as a pollutant. The chemical composition of water is a major factor in determining its quality (Gupta and Gupta, 1998). The stakeholders of Gournadi Upazila mainly use surface water for irrigating their crops, aquaculture, livestock farming, and other purposes

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