ASSESSMENT OF WATER QUALITY IN PUBLIC SCHOOLS OF RANGPUR CITY FOR DRINKING PURPOSE

Abstract

Groundwater is one of the most readily available natural resources for industrial and drinking purposes and it functions as a universal solvent. Water samples were collected from different locations of Sadar upazila of Rangpur district of Bangladesh and analyzed for quality assessment. Twenty samples were collected from groundwater sources of 20 schools around the upazila. Analyses included pH, Electrical conductivity (EC), Total Dissolved Solids (TDS), cations (Ca2+, Mg2+, Na+, K+) and anions (HCO3-, SO4 2-, PO4 3- and Cl-). Several computed variables such as Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), Hardness (HT), Potential salinity (PS), Gibbs ration (cation & anion), Kelly’s ratio and Permeability index (PI) were studied to evaluate the quality of water for drinking purpose. Almost all the water samples were acidic in nature (pH value varied from 5.92 to 7.08 with average 6.45). According to EC values almost all the collected water samples were categorized as “good” for drinking and all the samples were fresh on the basis of TDS (average was 176). Based on SAR values, all samples were classed as “excellent” in quality (average 1.25) and the best sample is found in Rangpur govt. college according to EC (1185) and TDS (440) value. For hardness all the samples were moderately hard (average was 37.21) and the best sample is found in Lalkhuthi Girls High School In respect of SSP, all the water samples were classed as “suitable” (average 23.39). The best sample is found in Rangpur Govt. College according to SAR (3.14) and SSP (48.59). On the basis of Ca, Mg content of all water samples can safely be used for drinking. The best sample is found in Lalkhuthi Girls High School and the range is Ca (9.80 mg L-1) and Mg (13.50) and on the basis of Na and K the best sample is found in Rangpur Govt. College range is (6.00 and 0.90), respectively. All the water samples may be consumed safely based on their levels of HCO3-, SO4 2-, PO4 3- and Cl-. Some correlations and compositional relations were also evaluated. According to Gibbs ratio (Cation and Anion) and Permeability Index (PI) the best sample is found in Rangpur Govt. College and the values of the sample is 0.69, 0.82 and 49.23 respectively. Seven of the twenty school samples were found to be the excellent sources for drinking water based on the observed results the sample of Rangpur Govt. College performed better in comparison to other tested samples. So, it can be concluded that the tested groundwater of Rangpur city can be used for drinking purpose.