Geochemical Survey and Estimation of Baseline Concentrations of Major and Trace Elements in Stream Water, Uttar Pradesh, India: Implication for Environmental Studies.

Stream water plays an important role in the development of habitats. It is one of the important sources of water used for drinking and irrigation in the region. Before using, it is necessary to test the quality of all types of surface water available for various use. A geochemical study of stream water has been conducted in parts of Pratapgarh, Raebareli, and Allahabad districts of Uttar Pradesh to assess its suitability for domestic purposes and establish the baseline concentration of major ions, trace and REEs. 20 samples of stream water from different locations of 1st or 2nd order streams were collected during post-monsoon period, from 18th to 31st October 2021. Different hydrochemical parameters such as pH, electrical conductivity (EC), temperature, dissolved oxygen (DO), salinity, total dissolved solids (TDS), major cations and anions were analysed. In order to obtain maximum quality and purity of water, the stream water samples were analyzed by ICP-MS analytical method in the chemical lab for 47 trace elements including REEs contents. The obtained values of each parameter have been compared with the standard values recommended by BIS and WHO. The value of each element except uranium has been found to be within the desirable and permissible limits prescribed by BIS (2012) and WHO (2006). Selenium and arsenic have been found to be marginally exceed the permissible limits. The pH values of all stream waters in the study area range from 7.14 to 8.86 with an average value of 7.86 indicating an alkaline nature of stream water. The concentration of uranium in stream water varied from 1.5 ppb to 48.67 ppb with a mean value of 7.9 ppb. It is observed that wherever concentration of uranium in the samples increased, the pH as well as the bicarbonate level increased accordingly. Correlation coefficient revealed that uranium is strongly correlated with bicarbonate (r=0.67), moderately with sodium (r=6.1), and low positively correlated with the concentration of pH (r=0.34), EC (r=0.52), and salinity (r=0.52), indicates the same origin. Water quality index (WQI) of water was determined for suitability of drinking purpose, revealed that 65% water samples fall in excellent category and 30% water samples fall in good category while only 5% water sample are in poor category. Trilinear plot of sample shows that most of the stream water samples are Ca-Mg-HCO3 type. [ABSTRACT FROM AUTHOR]