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Hydrochemistry, sources of ions, identification of pollution hotspot, and potability of groundwater in shallow and deep aquifers of Palakkad and Chittur taluks (area = 1875 km2) of Bharathapuzha river basin, the largest river basin in Kerala, India, are discussed in this paper. The study area belongs to one of the rice bowls of the State. Geologica...
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Groundwater in river basins serves as a prime source of freshwater for human consumption and agricultural needs. Effluent discharge from municipal, industrial, and irrigation activities contains undesirable dissolved chemicals that percolate into groundwater, posing human health risks. The present study investigated the distribution of heavy metals (HMs) including Iron (Fe), cobalt (Co), zinc (Zn), nickel (Ni), copper (Cu), selenium (Se), manganese (Mn), chromium (Cr), silver (Ag), lead (Pb), barium (Ba), cadmium (Cd), and aluminum (Al) in groundwater and their health implications at the Basuhi river basin (BRB) in Jaunpur, India. The mean concentration of HMs in groundwater samples was found to be in the order of Sr (697.2) > Al (582.56) > Zn (295) > Ba (83.8) > (57.71) > Fe (53.35) > Cr (4.96) > Pb (3.27) > Ni (2.90) > Cu (1.11) > As (0.55) > Se (0.54) > Ag (0.25) > Cd (0.22) > Co (0.22) µg/l. Further, the Modified Heavy Metal Pollution Index (m-HPI) and Heavy Metal Evaluation Index (HEI), coupled with multivariate statistical analysis, were also applied to evaluate the health risks to humans because of HM contamination. The HEI range varied between 2.70 and 8.10, with an average of 4.13, which can be considered low risk. Whereas, the m-HPI range for positive index (PI) was found to be 0.76 to 2.91 and negative index (NI) -0.44 to -0.65. Influence of m-HPI and PI results to be given noticeably 82.4% of samples have more than 1, which is not suitable for drinking, whereas, 17.6% of groundwater samples were found to be < 1 and require proper treatment before drinking. Pearson correlation coefficient (PCC) and principal component analysis (PCA) showed the impact of agricultural and industrial activities on groundwater quality. Open solid waste dumping sites and improper discharge of untreated/partially treated effluents may be the primary sources of HM pollution in the groundwater. Implementation of standard waste disposal practices and regular monitoring are required to avoid adverse consequences.
Groundwater resources are vital to ecosystems and livelihoods. Excessive groundwater withdrawals can cause groundwater levels to decline1–10, resulting in seawater intrusion¹¹, land subsidence12,13, streamflow depletion14–16 and wells running dry¹⁷. However, the global pace and prevalence of local groundwater declines are poorly constrained, because in situ groundwater levels have not been synthesized at the global scale. Here we analyse in situ groundwater-level trends for 170,000 monitoring wells and 1,693 aquifer systems in countries that encompass approximately 75% of global groundwater withdrawals¹⁸. We show that rapid groundwater-level declines (>0.5 m year⁻¹) are widespread in the twenty-first century, especially in dry regions with extensive croplands. Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the world’s regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.
Water quality index (WQI) models are generally used in hydrochemical studies to simplify complex data into single values to reflect the overall quality. In this study, deep groundwater quality in the Chittur and Palakkad Taluks of the Bharathapuzha river basin of Kerala, India, was assessed by employing the WQI method developed by the Canadian Council of Ministers of the Environment (CCME). The assessment of overall water quality is indispensable due to the specific characteristics of the study area, such as geography, climate, over‐drafting, and prevalent agricultural practices. Forty representative samples were collected from the study area for monsoon (MON) and pre‐monsoon (PRM) seasons. The results showed a general increase of contents from MON to PRM. The major cations were spread in the order Ca2+>Na+>Mg2+>K+ and the anions HCO3−>Cl−>CO32− based on their relative abundance. Among various parameters analysed, alkalinity and bicarbonate levels during MON were comparatively high, which is indicative of carbonate weathering, and 90% of the samples failed to meet the World Health Organization (WHO, 2017)/Bureau of Indian Standards (BIS, 2012) drinking water guidelines. The CCME WQI analysis revealed that nearly 50% of the samples during each season represented good and excellent categories. The samples in the poor category comprised 10% in MON and 15% in PRM. The overall WQI exhibited 15% of poor category samples as well. The spatial depiction of CCME WQI classes helped to expose zones of degraded quality in the centre to eastward parts. The spatial and temporal variations of CCME WQI classes and different physicochemical attributes indicated the influence of common factors attributing to the deep groundwater quality. The study also revealed inland salinity at Kolluparamba and Peruvamba stations, where agricultural activities were rampant with poor surface water irrigation.
