Evaluation of groundwater quality for irrigation and drinking purposes in Barishal district of Bangladesh

Abstract

A study was conducted to evaluate the quality of groundwater in Barishal district of Bangladesh for both irrigation and drinking purposes. Sixty wa- ter samples were collected and analyzed in the Biochemistry laboratory of Bangladesh Agricultural University for the assessment of their quality based on a number of parameters, viz. total dissolved solids (TDS), electrical con- ductivity (EC), sodium adsorption ratio (SAR), Kelly’s ratio (KR), residual sodium carbonate (RSC), soluble sodium percentage (SSP), pH and mag- nesium absorption ratio (MAR), salinity and alkalinity hazard, total cation and anion. Most of the water samples were found as acceptable in terms of TDS, EC, SAR and TH values, but unacceptable based on pH. Though the water samples were demonstrated as ‘good’ and ‘satisfactory’ water class in terms of SSP and KR, respectively, they were categorized as ‘harmful’ water class in term of MAR. However, in terms of salinity and alkalinity hazard, most of the water samples were found as ‘good water’ class for irrigation. In case of drinking purpose, most of the samples were found as ‘permissi- ble’, ‘good’ and ‘safe’ based on EC, pH, and TDS, respectively. Though the samples were demonstrated as ‘suitable’ and ‘good’ water class in terms of TH and nitrate, respectively, they were classified as ‘unsatisfactory’ based on sulphate. Overall for the groundwater samples, SSP–KR and pH–TH had a very strong correlation with a correlation coefficient around 1, and EC, TH and pH showed a negative correlation with most of the parameters. The study revealed that the quality of groundwater for most of the locations in the area was permissible and good for irrigation and drinking purposes.