地球科学与气候变化杂志

抽象的

Groundwater Quality and its Suitability for Irrigation and Domestic Purposes: A Study in Rajnagar Block, Birbhum District, West Bengal, India

Nag SK* and Suchetana B

Groundwater is indispensible for continuity of life and sustainability of ecosystem. It is needed in almost every sphere of human activity. Hence, this study is aimed at assessing the ground water quality in Rajnagar block, Birbhum district, West Bengal, India, with respect to drinking and irrigation uses. A total of 17 groundwater samples each for both post- and pre-monsoon periods have been collected. The physical parameters pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS) have been determined in the field itself. The samples were analysed for cations like Ca, Mg, Na, K and anions like Cl, HCO3 and SO4. Overall, the groundwater in the study area is found to be slightly acidic to basic (pH ranging from 6.32 and 7.26 in pre-monsoon and 6.3 to 7.33 in post-monsoon) and moderately hard to very hard (Total Hardness ranging from 109.39 mg/L and 2328.43 mg/L in premonsoon and 60.6 mg/L and 969.79 mg/L in post-monsoon) in nature. Concentration of sulphate is above the maximum permissible limit in seven of the post-monsoon samples. Piper’s diagram indicates groundwater is mostly of bicarbonate type. Groundwater of the study area is moderately suitable for drinking. Water Quality Indices (WQI) indicates 75% of pre-monsoon samples are excellent to good for drinking purposes whereas the value reduces to 56% during postmonsoon. The calculated values of Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC) and Soluble Sodium Percentage (SSP) indicate well to permissible range of water for use in irrigation. Magnesium Adsorption Ratio (MAR) and RSC values at some sites limit use for agricultural purposes. Ground water chemistry is controlled by rockwater interaction as expressed by Gibb’s diagram.