Groundwater quality (subsurface groundwater) in the Lesser Himalaya is controlled by the interplay of geogenic and anthropogenic processes. This study assessed 32 spring-water samples from the Pithoragarh district during pre-monsoon and post-monsoon seasons, integrating major ions and trace metals (Cr, Pb, Cu, Fe, Mn, Zn, U) to elucidate hydrogeochemical processes and implications for drinking and agricultural use. The results indicate that groundwater ranges from mildly acidic to alkaline in nature and is primarily dominated by HCO3- and Cl- among anions and Mg2+ and Ca+ among cations. Elevated HCO3- concentrations and high HCO3-/(HCO3- + SO42-) ratios (>0.5) indicate that carbonic acid weathering is the primary driver of solute chemistry. Gibbs and Piper diagrams further confirm that rock-water interaction is the dominant hydrogeochemical process, with localized influence from anthropogenic activities. Quantitative assessment indicates that rock-water interaction accounts for around 71.9% of the governing processes, while Mg2+ and Ca2+ together contribute more than 75% of the total cation concentration. Similarly, HCO3- and Cl- collectively account for nearly 90% of the total anion concentration. Seasonal shifts in hydrochemical facies (Ca-Mg-HCO3, Ca-Mg-SO4, Na-K-Cl, and mixed ion types) reflect variable water-rock interaction intensities. Irrigation suitability is generally favorable, though site-specific salinity and magnesium hazards may impair long-term use. Multivariate analysis showed that 82.82% of pre-monsoon variance was controlled by Mg2+, HCO3-, TDS, EC, and Ca2+, underscoring their geochemical significance. Overall, the findings advance our understanding of Himalayan aquifer vulnerability under seasonal and environmental stressors, with implications for groundwater management, sustainability, and public health in complex mountain terrains.

Abstract Mayurbhanj district is predominantly inhabited by tribal communities. Among the various tribal groups in Odisha, Mayurbhanj alone accommodates 45 distinct categories. These tribal communities primarily rely on natural water sources such as rivers, streams, and tube wells for drinking purposes without undergoing additional purification processes. Hence, investigating the factors affecting groundwater quality is essential to ensure its safety for drinking purposes and mitigate the health risks associated with the consumption of contaminated water. In the present study, groundwater quality of 145 water samples from different sources of Mayurbhanj district was analysed. The geographical coordinates of sample locations and measurements of groundwater quality parameters were used in Geographic Information System software, ArcGIS pro, to construct the spatial distribution and spatial variation maps. Five significant principal components having eigen value greater than 1 with total variance of 73.43. Kaiser-Meyer-Olkin (KMO) test was above 0.5 which shows that data collected from the study area are accurate for analysis. Electrical conductivity, F−, pH and NO3− varies in the range of 42 to 1754 µS/cm, 0.01 to 1.97 mg/l, 5.5 to 7.9 and 0.1 to 21.2 mg/l respectively. The non-carcinogenic health risk assessment indicates that the hazard quotient (HQ) values attributed to fluoride ion and nitrate ion exposure range from 0.43 to 0.46 for children and 0.23 to 0.26 for adults, and from 0.002 to 0.6 for children and 0.001 to 0.3 for adults, respectively. The children are comparatively at slightly more prone to health risk in comparison to adults. Gibbs diagram shows that most of the water samples comes in the region of rock-water interaction dominance in Gibbs plot of TDS vs chloride ion concentration. In the loading biplot for the study area, the first principal component in the horizontal axes has positive coefficients for carbonate, chloride, bicarbonate, total alkalinity, calcium hardness, magnesium hardness, total dissolved solids, electrical conductivity, fluoride. TDS has positive correlation with EC (0.98), chloride (0.525), nitrate (0.445), sulphate (0.445), total hardness (0.438), total alkalinity (0.524), carbonate (0.528) and bicarbonate (0.535). The software used for statistical study are, Minitab, Origin and SPSS. The results of this study would be useful for the Government and policy makers to provide safe and quality drinking water to the tribal community.

Groundwater contamination in industrially and agriculturally influenced regions poses serious risks to drinking water security and sustainability, requiring rapid and reliable quality assessment. In this study, Bayesian hyperparameter (HP) optimized artificial neural network (ANN), random forest (RF), and simple multiple linear regression (MLR) models were developed for groundwater quality index (WQI) based on a single post-monsoon sampling campaign of groundwater samples (12 hydrochemical parameters) from Jajpur district, Odisha. The fitness of the HP-optimized single hidden layer 6-neuron ANN (R2: 0.999, R2CV: 0.991) was superior to that of the RF model (R2: 0.945, R2CV:0.792). Following the assessment of model quality (resilience, validation, and predictor importance), different filter- and wrapper-based feature selection strategies were adopted to enhance model interpretability and robustness. Bayesian HP optimization integrated feature selection for the ANN (R2CV: 0.981) and the RF model (R2: 0.936, R2CV: 0.830), respectively, retained eight and five features, respectively. The study provides a transparent, data-efficient ML-based framework for WQI prediction, offering practical value for groundwater monitoring and evidence-based policy interventions.

The sustainability of groundwater in Mayurbhanja, Odisha, is in grave danger, despite its role as the primary water source for the localities. A systematic hydrogeochemical investigation of 92 groundwater sampling points found an average Water Quality Index (WQI) of 68.74, categorizing most sources as “poor” and unsuitable for direct consumption. Fluoride reaching 20.3mg/L, tenfold the WHO limit, alongside increased levels of nitrate. Significant risks of methemoglobinemia and fluorosis were suggested by health risk assessment, which showed hazard quotient (HQ) values of 1.15 for nitrate and 0.813 for fluoride, particularly for vulnerable groups such as children. Groundwater contamination in the study area caused by geogenic factors like weathering of metamorphic and sedimentary rocks and anthropogenic sources such as agricultural runoff and insufficient sanitation. Principal Component Analysis (PCA) successfully identified five geochemical components responsible for 76.73% of the variance. Significant correlation between hardness, bicarbonate, and chloride serve as clear indicator of the effect of mineral dissolution and carbonate equilibrium. With an LSI of −3.94 and AI of 9.90, the water exhibits a tendency towards corrosion, suggesting potential infrastructure deterioration and subsequent metal leaching. These findings act as a reminder that technical failures in water distribution come with consequences for community health. Untreated groundwater poses an alarming risk to tribal communities; ensuring long-term water security requires source protection, resilient infrastructure, and grassroots- level monitoring for public health.

The average total dose received by the global population is significantly influenced by naturally occurring terrestrial gamma radiation. Evaluating radiation levels are essential for establishing the baseline data. In this perspective, gamma radiation is monitored in the study region in two seasons, i.e., pre- and post-monsoon periods. In this study, outdoor gamma radiation in the Alwar district of Rajasthan (India) was systematically measured using the Geiger-Muller technique. The gamma radiation was found to range between 65 nSv/h and 160 nSv/h, with an average value of 112.11 nSv/h. The annual effective dose (AED) of outdoor gamma radiation was estimated to range between 0.114mSv/year to 0.280 mSv/year. The AED values at all locations in both pre-and post-monsoon seasons are found below the recommended level of AED of 1.0 mSv/year (International Commission on Radiological Protection, 1996).

This study evaluates uranium (U) concentrations in drinking water from Dhaulpur district, Rajasthan, using LED fluorimetry. Groundwater samples were collected during pre-monsoon (March 2019) and post-monsoon (October 2019) period to analyze seasonal variations in uranium contamination. Uranium concentrations ranged from BDL(below detection limit) to 23.3 µg/L with an average of 3.7 µg/L in the pre-monsoon (PRM) and from 0.2 to 43.5 µg/L with an average of 7.8 µg/L in the post-monsoon (POM) period. Approximately 3

The pioneer work on the measurement and distribution of natural radioactivity levels was carried out in the sediment samples of Asia's largest coastal lagoon, Chilika, India. The activity concentrations of radionuclides in the sediment samples measured by using a high-resolution HPGe semiconductor detector gamma-ray spectroscopy system, and the average activity concentration of 226Ra, 232Th, and 40K were found to be 28.25 ± 7.85, 84.27 ± 30.93 and 610.57 ± 89.74 Bq kg-1. The contour map, drawn using the Kriging method, illustrates the geospatial distribution of each radionuclide in Chilika. The results show the distribution of radionuclides and are compared with similar results from different locations in the worldwide. The activity concentrations are also compared with the average values of the world and India. The radiological indices for the lagoonal system were calculated, and the mean values are 195.77 Bq kg-1 for radium equivalent (Raeq), 167.53 nGy h-1 for absorbed gamma dose rate (DR), 0.21 mSv y-1 for annual effective dose equivalent (AEDE), 631.27 µSv y-1 for Annual gonadal dose equivalent (AGDE), 0.53 for external hazard index (Hex), 0.61 for internal hazard index (Hin), 0.72 for gamma representative level index (Iγr), and 0.14 for alpha index (Iα). The mean value of the Raeq obtained from the study area was less than the international value of 370 Bq kg-1. All the radiological assessment indices indicated that the observed values are below the threshold values.

Groundwater quality in Deogarh district, Odisha, was assessed with a focus on fluoride contamination and its potential impact on human health. While most samples showed fluoride levels within safe limits, about 5.3% exceeded the permissible standards set by WHO, BIS, and USEPA, raising health concerns. Interestingly, 76% of the samples had fluoride levels below the recommended minimum, which could lead to issues such as dental caries and weakened bones. Based on the water quality index (WQI), the groundwater in the area was classified as moderately polluted. A clear link was observed between higher fluoride levels and factors like increased pH and bicarbonate concentration, suggesting that natural rock weathering plays a major role in fluoride release. Human activities, including the use of chemical fertilizers, pesticides, and industrial waste discharge, further contribute to the contamination. Health risk analysis showed that children are more vulnerable to fluoride exposure than adults. These findings highlight the urgent need for better water management practices, regular monitoring, and awareness to ensure safe drinking water for communities in the region.

Analysis of U, Cr, Ni, As, Mo, Cd and Pb was performed in Ganga water in Uttarakhand state of India using Inductively Coupled Plasma Mass Spectrometry (ICPMS). Seasonal and spatial variability in the analyzed Potentially Toxic Elements (PTEs) concentrations were observed in Ganga water in this study. The health risks of PTEs in Ganga water were estimated as pollution indices, hazard quotients and cancer risk. The estimated risk assessment parameters show that Ganga water is not contaminated by the analyzed PTEs in the investigated region. A multivariate statistical analysis of the obtained dataset was performed to identify the pollution sources.

The presence of fluoride and nitrate is a serious groundwater quality issue in India impacting human health. In the present study, 14 different hydrochemical parameters for 76 groundwater samples collected from the Jajpur district of Odisha, India, were evaluated. Entropy-weighted water quality index (EWQI), fixed-weight groundwater quality index (GWQI), principal component analysis (PCA), and rotated factor loading-based water quality index (PCWQI) were employed to assess groundwater quality. About 65.79 ± 4.68

This study was undertaken to evaluate concentration of Uranium (U) in the drinking water of the Tonk district of Rajasthan (India). The main objective of the study is to determine the distribution of Uranium concentration and the geochemical behavior of Uranium in pre -monsoon (PRM) and post-monsoon (POM) drinking water samples. Uranium was measured by LED fluorimeter. Total 318 drinking water samples were collected for both seasons. It is observed that the water quality of all the samples is within the limits prescribed by WHO (30 mu g/L) except a few, and can be used for domestic purposes. The Uranium concentration was found to be in the range 0.21 to 173.72 mu g/L with a mean value of 8.58 mu g/L in pre-monsoon and 0.21 to 162.34 mu g/L with a mean value of 11.22 mu g/L in post-monsoon samples. The geochemistry of the study area shows rock-water interaction. The order of average anionic concentration is found to be HCO3 (-) > Cl- > SO4 (2- )> NO3 (-). Although no definite trend of seasonal variation in the concentration of U was observed, large samples have higher Uranium concentrations in post-monsoon than pre-monsoon.

Large quantity of the feed forms part of the solid waste (tailings) slurry in the low grade uranium ore processing plant at Turamdih in Singhbhum region of Jharkhand, India. Coarser size fraction of this waste is used for backfilling of the underground uranium mines and fine fraction is discharged into an engineered impoundment system or tailings pond. Since inception of the discharges, field expeditions have been performed as part of the comprehensive radiological monitoring program for the facility. The monitoring program broadly consists of ambient gamma dose rate, atmospheric 222Rn and long lived alpha activity measurement around the facility and the estimation of radionuclide in diverse environmental matrices collected from the adjoining sites. Findings reflect that the radiological conditions are comparable to the pre-existing background level adjoining the tailings pond impoundment. Further, measurements for more than a decade confirm that the atmospheric radon concentration profile just a few meters beyond the embankment is indistinguishable from the background.

This paper presents a novel transition to a low-index core dielectric waveguide (LICDW) from a lightweight, low-profile, and compact probe-fed substrate integrated waveguide (SIW) for Ku-band applications. The proposed transition design employs a tapered SIW section that efficiently excites the dominant E-11(y) mode in the LICDW section using the dominant TE10 mode of the SIW section. Comprehensive simulation results of a Ku-band back-to-back prototype, along with extensive field analysis, confirm the effective excitation of the dominant mode within the LICDW. The transition has been fabricated and experimentally validated, with results matching the simulations. It demonstrates excellent performance, achieving a transmission coefficient better than 3.2 dB and a reflection coefficient better than 14 dB across the entire Ku-band, underscoring its suitability for Ku-band applications.

A comprehensive investigation was engaged to determine the spatial distribution of Uranium (U) and the consequential chemical and radiological health risk associated due to the consumption of groundwater containing U, in Panchkula district. A well -ac-cepted technique of fluorescence of U estimation in an aqueous medium was employed having a detection limit of 0.50 mu gL-1. The chemo-radiological health risk and water quality index was computed using a standard equation of concerned agencies to deter-mine the suitability for human health. The concentration of U was observed to vary from 1.70 - 12.28 mu gL-1 with the mean value of 5.89 mu gL-1 The concentration of U was far below the standard prescribed limits as per World Health Organisation, Atomic Energy Regulatory Board, and United Nation Environmental Protection Agency. Ex-cept nitrate and total alkalinity in few samples, all water quality paramters were within the recommended limit of BIS. The annual effective dose (AED), excess cancer risk (ECR), and lifetime average daily dose (LADD) indicated no potential health issue due to the consumption of groundwater of studied locations. The correlation was computed between U and various macro-anions and cations present in water samples. U was ob-served to have a significant weak positive correlation with total dissolved solids (TDS), electrical conductivity (EC), and salinity.

A pilot survey in the Central Garhwal Himalayan region, India, assessed radon and thoron inhalation doses using RADUET, CR39 detectors during January to October 2013. Detectors were deployed for 95, 101, and 92 days in winter, summer, and in the rainy season respectively. Highest 222Rn concentration (260 ± 13 Bqm−3) was in cemented categories, followed by 170 ± 8 and 190 ± 10 Bqm−3 in wood-stone dwellings. Wood-mud categories had lower levels (116 ± 6 to 128 ± 8 Bqm−3). Despite significant 222Rn concentration, analysis of seasonal radiation exposures (EECTn and Feq) with short-lived decay products showed reduced doses in winter months ranging from 2.97 (± 0.31) to 6.91 (± 0.32) Bqm−3.

Abstract The groundwater chemistry is significant before it is utilized. It is influenced by the region's geology, hydrogeology, geochemistry, and climatic conditions. The groundwater hydrogeochemistry of Aurangabad city was examined in this investigation, which was backed by geographical distribution mapping. Standard procedures were employed to assess the water quality parameters as well as the uranium concentration. Several water classification techniques, including the Piper trilinear diagram, the Durov diagram, and the Chadha classification, are used to assess groundwater type and the sorts of geochemical processes that occur in the studied area. Groundwater was also evaluated for its suitability for drinking and irrigation purposes using a set of metrics. Stage-by-stage quality control and assurance were used to ensure data quality. The correlation analysis test is employed to assess the associations between parameters. According to assessed indices, the groundwater in the study area is acceptable for drinking and irrigation.

Singrauli coal fields are air polluted in an industrial town in India. The contribution of anthropogenic activities to increased particulate matter (PM) in the study area has been calculated. The size-segregated PM was collected in 2016 and 2017 and carried out for morphological and composition analysis. PCA (principal component analysis) and PMF (positive matrix factorization) were applied to quantify for identification and apportionment of sources. Based on the study, biomass burning and vehicular emission were the primary source of particulate matter; and PCA and PMF identify the contribution of biomass burning, vehicular emission, mining activity, resuspended dust, secondary inorganic aerosols, and traffic-related emission as the major sources of particulate matter in Singrauli coalfield.