0016-7622/2014-83-3-329/$ 1.00 © GEOL. SOC. INDIA JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol.83, March 2014, pp.329-343 Hydrogeochemical Investigation and Groundwater Quality Assessment of Pratapgarh District, Uttar Pradesh ASHWANI KUMAR TIWARI and ABHAY KUMAR SINGH CSIR - Central Institute of Mining and Fuel Research, Barwa Road, Dhanbad - 826 015 Email: singhak.cimfr@gmail.com Abstract: Hydogrochemical investigation of groundwater resources of Paragraph district has been carried out to assess the solute acquisition processes and water quality for domestic and irrigation uses. Fifty-five groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids, hardness, major anions (F - , Cl - , NO 3 , HCO 3 - , SO 4 2- ) and cations (Ca 2+ , Mg 2+ , Na + , K + ). Study results reveal that groundwater of the area is alkaline in nature and HCO 3 - , Cl - , Mg 2+ , Na + and Ca 2+ are the major contributing ions to the dissolved solids. The hydrogeochemical data suggest that weathering of rock forming minerals along with secondary contributions from agricultural and anthropogenic sources are mainly controlling the groundwater composition of Pratapgarh district. Alkaline earth metals (Ca 2+ +Mg 2+ ) exceed alkalis (Na + +K + ) and weak acid (HCO 3 - ) dominate over strong acids (Cl - +SO 4 2- ) in majority of the groundwater samples. Ca-Mg-HCO 3 and Ca-Mg-Cl-HCO 3 are the dominant hydrogeochemical facies in the groundwater of the area. The computed saturation indices demonstrate oversaturated condition with respect to dolomite and calcite and undersaturated with gypsum and fluorite. A comparison of groundwater quality parameters in relation to specified limits for drinking water shows that concentrations of TDS, F - , NO 3 - and total hardness exceed the desirable limits in many water samples. Quality assessment for irrigation uses reveal that the groundwater is good for irrigation. However, values of salinity, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), %Na and Kelley index are exceeding the prescribed limit at some sites, demanding adequate drainage and water management plan for the area. Keywords: Pratapgarh district, Groundwater quality, Hydrogeochemical processes, Sodium percent, Sodium adsorption ratio, Residual sodium carbonate, Kelley index, Uttar Pradesh. INTRODUCTION Water resource has played a critical and vital role throughout the history in the growth and development of human civilization. In modern times, water resources have critical importance in the economic growth of all contemporary societies. Therefore, water resource assessment and sustainability consideration are of utmost importance, especially, in the developing countries like India where water is commonly of economical and social significance. Access to safe drinking water remains an urgent necessity, as 30% of urban and 90% of rural Indian population still depend completely on untreated surface or groundwater resources (Kumar et al. 2005). Water quality plays an important role in promoting agricultural production and standard of human health. While access to drinking water in India has increased over the past decades but the tremendous adverse impact of unsafe water on health continues. Scarcity of clean and potable drinking water has emerged in recent years as one of the most serious developmental issues in many parts of West Bengal, Jharkahnd, Orissa, Western Uttar Pradesh, Andhra Pradesh, Rajasthan and Punjab. Public ignorance to environmental considerations, indiscriminate disposal of anthropogenic, agricultural and mining wastes, unplanned application of agrochemicals and fertilizers and overexploitation of groundwater resources caused excess accumulation of pollutants on the land and contamination of available surface and groundwater resources (Subramanian 2000; Singh 2000; CPCB 2008). The overdependecy on groundwater has led to 66 million people in 22 states at risk due to excessive fluoride and around 10 million at risk due to arsenic in six states (Ghosh 2007). This indicates endemic fluorosis has emerged as one of the most alarming public health problems in the country (Choubisa 2001; Susheela et al. 1993; Susheela 1999; Teotia and Teotia 1984). In addition, there are problems due to excessive salinity and hardness of groundwater in the coastal areas of Andhra Pradesh, Tamil Nadu, Gujrat, NCR (National Capital Region of Delhi) and Western Uttar Pradesh and higher concentration of iron and nitrate in the Andhra Pradesh,