Post-monsoon Samples Research Articles

A comprehensive analysis of groundwater quality: Geospatial and multivariate approaches in Dindigul District, Tamil Nadu, India

This study focuses on a comprehensive analysis of groundwater quality by integrating hydrogeochemical, geospatial, Multivariate Statistical Approaches (MSA), and water quality indices (WQI), along with visualization techniques, in the Dindigul district of Tamil Nadu, India. A total of 69 water samples, collected during pre-monsoon (PRM) and post-monsoon (POM) periods by the Public Works Department, Tharamani, were analyzed for major cations (Na+, Ca+, Mg+, K+), anions (Cl-, SO4-, HCO3-, NO3-), and various physical and chemical parameters such as pH, Total Dissolved Solids (TDS), and Electrical Conductivity (EC). The Water Quality Index (WQI) for Bureau of Indian Standard was calculated to assess water quality for drinking purposes. PRM samples showed poorer water quality due to ion dilution and agricultural influence compared to POM samples. The WQI revealed that 3.4 % of the PRM area had excellent water quality, 40.72 % good, 35.54 % poor, 18.41 % very poor, and 1.91 % unsuitable for drinking. In the POM period, 6.34 % of the area was classified as excellent, 51.03 % good, 40.09 % poor, 2.45 % very poor, and 0.08 % unsuitable. Irrigation water quality indices, including Sodium Percentage (Na%), Sodium Adsorption Ratio (SAR), Kelly's Ratio (KR), Magnesium Hazard (MH), Residual Sodium Carbonate (RSC), and Permeability Index (PI), were also computed to identify suitable zones for sustainable agriculture. Correlation analysis indicated significant positive relationships between TDS and other parameters, like Bicarbonate, Total Hardness, Chloride, and EC during PRM, and Sulphate, Total Hardness, Calcium, Chloride, Sodium, and EC during POM, suggesting that TDS is a key indicator of water quality variations in both periods.

Insights into the seasonal variation, distribution, composition and dynamics of microplastics in the Ganga River ecosystem of Varanasi City, Uttar Pradesh, India.

The current study explores the seasonal dynamics of microplastic (MP) pollution in the Ganga River of Varanasi City, Uttar Pradesh, India, focusing on water and sediment samples collected during pre-monsoon and post-monsoon periods. The analysis shows significant variations in MP occurrence, shape dynamics, color distribution, and size composition across diverse sampling sites. During the pre-monsoon season, MP concentrations ranged from 17 to 36 particles/L in water samples and 160 to 312 particles/kg in sediment, indicating a moderate to high level of contamination. Post-monsoon sampling showed higher MP concentrations at most sites, indicating the influence of seasonal hydrological changes on MP distribution. Shifts in MP shape dynamics were observed between seasons, with films, foams, fragments, and filaments showing variable distributions. Similarly, color variations in MPs exhibited site-specific patterns, with white, brown, blue, and other colors being predominant. These findings highlight the diverse sources and compositions of MPs in the river ecosystem, highlighting the complexity of MP pollution dynamics. Polymer-type distributions further elucidated the composition of MPs, with notable contributions from polyethylene terephthalate, rayon, polyester, and polyvinyl chloride. PCA analysis revealed significant shifts in particle size and shape distribution between pre-monsoon and post-monsoon periods in both water and sediment samples, with post-monsoon samples showing an increase in larger particles and filaments. These changes highlighted key factors driving the variance in microplastic contamination across different sites. The prevalence of these polymers features diverse sources of MP pollution, including textiles, packaging materials, and industrial waste. Ongoing monitoring and research are crucial to understanding its sources, distribution, and impact on river ecosystems, essential for protecting aquatic biodiversity and human health.

Health hazards from perchlorate enriched groundwater of a semi-arid river basin of south India and suggesting in-situ remediation through Managed Aquifer Recharge

The present study was conducted to assess the groundwater quality and perchlorate contents in the pre- and post-monsoon groundwater samples along with its associated health concerns with suggesting in-situ remediation in semi-arid Arjunanadi River basin of south India. Most of the samples (86 in pre-monsoon and 84 in post-monsoon out of total 94) showed secondary salinity and secondary alkalinity, and the perchlorate showed positive relations with Na+, K+, SO42-, Cl-, and NO3- contents. The main source of perchlorate could be fireworks manufacturing industries with 23 % of pre-monsoon (246.5 km2) and 33 % of post-monsoon samples (360 km2) showing perchlorate above the World Health Organization (WHO) standard (>0.07 mg/l). Perchlorate health risk assessment (PHRA) and total hazard index (THI) indicated more effect from oral pathway compared to the dermal pathway with about 80 %, 79 %, 65 %, and 60 % of samples causing health complications for infants, children, women, and men during the pre-monsoon. The post-monsoon groundwater showed increased health risks with 90 %, 82 %, 74 %, and 69 % of samples remaining hazardous for infants, children, women, and men. Artificial recharge through Managed Aquifer Recharge (MAR) techniques in the high-risk area could be useful to minimize the perchlorate contamination in groundwater and associated health risks under the United Nations Development Programme (UNDP) Sustainable Development Goals 3 and 6 (SDGs) for a healthy society.

Identifying seawater interaction with coastal aquifers using hydrochemical and GIS for Nagapattinam district, southeast coast of India

Groundwater chemistry of the two different seasons collected between 2020–2021 from the coastal areas of Nagapattinam, Mayiladuthurai and Karaikal in Tamil Nadu state of southeast India were evaluated for seawater intrusion into coastal aquifers. Groundwater types, its classification was evaluated to know the extension of seawater intrusions into coastal aquifers using the Groundwater Quality Indices (GQI) such as GQIPiper(mix), GQIPiper(dom), fsea, GQIfsea and GQISWI. Piper diagram grouped most samples (GQIPiper(mix) and GQIPiper(dom)) in domain-II, representing Na-Cl water type, followed by domain-IV, indicating mixed Ca-Mg-Cl water for both the seasons. As measured by the saltwater Intrusion as Groundwater Quality Index (GQISWI), about 62.5 % and 37.5 % of the pre-monsoon samples showed low saltwater intrusion and moderate seawater intrusion, respectively. In the post-monsoon samples, the low saltwater intrusion increased to around 82.5 % and the moderate seawater intrusion decreased to 17.5 % of the groundwater samples. The GIS framework was used to display the geographical distribution of groundwater types as well as the delineation of vulnerable zones from seawater intrusion.

Hydrogeochemical and GIS Analysis of Groundwater Quality for Drinking and Irrigation Purposes in Kuzhithuraiyar Sub-Basin, Kanniyakumari District, Tamil Nadu, India

A hydrogeochemical analysis was conducted to find the suitability of the groundwater for drinking and irrigation purposes in the Kuzhithuraiyar sub-basin, Kanniyakumari district, Tamil Nadu, India. 48 groundwater samples were collected from the different locations of the study area during both the pre- and postmonsoon periods. This study assesses the groundwater quality for drinking and irrigation purposes based on the analytical results, water quality index, Wilcox plot, and irrigation parameters such as electrical conductance, Kelly’s ratio, sodium absorption ratio values, magnesium hazards, bicarbonate, and the residual sodium carbonate index. The pH values ranged from 8.5 to 6.5, suggesting generally acceptable conditions. TDS concentrations range from 24 to 1277 mg/L, whereas EC values range from 37.50 to 1996 μS/cm. It is observed from the collected samples that the pre-monsoon water samples TDS’ values were exceeded the recommended TDS limits than postmonsoon samples. Water quality indices indicate that 50% of premonsoon samples and 48% of postmonsoon samples are suitable for drinking. In total, 10% of samples are admissible to a doubtful category before and after the monsoon, 6% are good to permissible during the monsoon, and 84% are good to permissible. Kelly’s ratio shows that 56% and 48% of samples collected during the post- and premonsoon are suitable for irrigation, respectively, whereas the remaining samples are not. Due to magnesium hazards, 40% and 44% of pre- and postmonsoon samples are not suitable for irrigation. Overall, the postmonsoon samples exceeded the permissible TDS limit (1000 mg/L) by 10% and the premonsoon samples by 6. 13% of samples obtained after the monsoon and 19% collected before the monsoon have a potential salinity greater than three, indicating that these samples are unacceptable. The sustaining water quality and mitigating possible hazards in the Kuzhithuraiyar sub-basin require continuous monitoring and focused measures.

GROUNDWATER QUALITY ANALYSIS AND ITS IMPACT ON AGRICULTURAL PRODUCTIVITY: A CASE STUDY

Ground water quality of twenty villages selected were from Karad taluka in Satara district was assessed during pre and post monsoon in the year 2017. The ground water samples were collected from bore wells and open wells, and their quality parameters were assessed for following attributes such as pH values ranges from in pre-monsoon and in post-monsoon, EC values in pre-monsoon and in post-monsoon of the samples. Most of the samples were found to be magnesium dominating in the pre-monsoon and in post-monsoon Ca2+ exceeds the Mg content in most of the water samples. The observation for post monsoon can result in Mg2+ toxicity which will be exhibited due to the continuous use this of water to crops. Cations and anions concentration varies in post-monsoon is Ca-8.251meq/L, Mg2+-11.05 meq/L, CO3-5.275 meq/L, HCO3-10.85, K-21.781, Na2+-8.73 respectively while in pre-monsoon Ca2+-9.625 meq/L, Mg2+-10.248 meq/L, CO3- 2.672meq/L, HCO3-8.762meq/L, K-13.092meq/L, Na-14.382meq/L respectively. Some parameters are analyzed statistically such as Mg Hazard, RSC, SSP, KR, RSBC, PI etc.to determine better efficiency of observations. RSC values varied from 1.1-25.2 meq/L in pre-monsoon and 80 % samples are under unsafe while 5 % are in moderate range, 15 % are safe in post-monsoon 1.1- 28.2 meq/L and 85 % are in unsafe, 5 % in moderate,10 % in safe mode, 5 % moderate, 10 % in safe mode for irrigation. SSP values in samples varied from 6.222-79.452 % (post-monsoon) to 6.671-72.84 % (Pre-monsoon); 35 % samples were good while 65 % samples were found unsuitable in pre-monsoon samples and 50 % good while 50 % unsafe in post-monsoon samples respectively. KR values in pre-monsoon observed 0.0303-6.22 meq/L while in post-monsoon it was 0.143 to 72.631 meq/L; according to Kelley’s ratio 75 % in suitable, 5 % marginal and 20 % unsuitable in pre monsoon while 65 % suitable, 5 % marginal, 30 % unsuitable for agriculture. RSBC values are observed in pre-monsoon 1.0-8.65 while in post-monsoon 0.f3-8.65 Permeability Index (PI) also analyzed it was observed in pre-monsoon 14.208-95.661 % in post-monsoon 15.327-71.549 was observed samples are under the categories of 15 % suitable, 55 % good (class II), 30 % unsuitable (class III) in pre-monsoon and 75 % good (class II), 25 % unsuitable (class III). The most of the analyzed water samples are under alkaline category; alkaline water should be managed carefully to avoid negative impacts on crops as well as on soil.

Evaluation of hydrogeochemical processes and saltwater intrusion in the coastal aquifers in the southern part of Puri District, Odisha, India.

Groundwater is widely regarded as being among the freshwater natural resources with the lowest levels of contamination. Nevertheless, the saltwater intrusion has resulted in the contamination of groundwater in coastal regions with lower elevation. The rationale of the present work is to investigate the chemistry of groundwater, to identify the various facies of groundwater, to identify the processes that influence groundwater chemistry and saltwater intrusion, and to evaluate the groundwater's aptness for use in drinking and farming. In order to gain an understanding of the groundwater quality as well as the salinization process that occurs in coastal aquifers as a result of hydrogeochemical processes, a total of 108 groundwater samples (54 each in pre- and post-monsoon) were taken and analyzed for several physiochemical parameters in the southern part of the Puri district in the Indian state of Odisha. The data has undergone analysis and examination to identify the factors (such as hydrological facies, potential solute source in water, and salinization process) that contribute to groundwater salinity. The result showed the chemistry controlling processes of rock-water interaction as per Gibbs diagram. The majority of shallow aquifers exhibit the Na-Cl type of facies as per the Piper plot. A total of 37% pre-monsoon and 33% post-monsoon samples having Na+/Cl- ratio below the threshold of 0.86 indicating the influence of saltwater intrusion. In both seasons, it was observed that 74% of the samples exhibited a Na+ concentration that exceeded the permissible limit set by the World Health Organization (WHO) for drinking purposes. The findings indicate that most groundwater failed to pass safe drinking water and irrigation standards due to saltwater intrusion. Consequently, the monitoring of coastal aquifer quality has become imperative in order to ensure the sustainability of aquifers and the development of groundwater resources. This is because coastal aquifers are highly vulnerable to saltwater intrusion, primarily as a result of the extensive extraction of groundwater for diverse purposes.

Elemental (CNS) and isotopic (δ13C and δ15N) characterization of local sources to atmospheric dust at Trombay, Mumbai, using elemental analyzer–isotope ratio mass spectrometry

Particulate matter (PM) in the air has significant implications for human health and the environment, particularly in urban areas with high concentrations. This study focuses on the isotopic (δ13C and δ15N), elemental (CNS) as well as the total carbon to total nitrogen ratio (TC/TN) characterization of PM in Trombay, Mumbai. Monthly atmospheric dust samples were collected from 2016 to 2020 during the premonsoon and postmonsoon seasons. The average elemental concentrations for premonsoon samples were N (1.73% ± 0.25%), C (7.38% ± 0.72%), S (0.84% ± 0.13%), and TC/TN ratio (4.38 ± 0.86). For postmonsoon samples, the average elemental concentrations were N (1.47% ± 0.185%), C (6.95% ± 1.04%), S (0.84% ± 0.13%), and TC/TN ratio (4.80 ± 0.94). The average δ13C values for premonsoon and postmonsoon seasons were −24.31 ± 1.15‰ and −24.56 ± 1.20‰, respectively. The average δ15N values for premonsoon and postmonsoon seasons were 5.22 ± 1.92‰ and 4.57 ± 1.32‰, respectively. The results showed variations in elemental concentrations between the seasons, with higher values observed in premonsoon samples which can be attributed to increased dust generation from land and sea. Overall, this study provides insights into the local sources and characteristics of PM in the Trombay area and highlights the importance of long-term monitoring to understand the seasonal variations in PM composition.

Assessing Groundwater Quality for Sustainable Drinking and Irrigation: A GIS-Based Hydro-Chemical and Health Risk Study in Kovilpatti Taluk, Tamil Nadu

The continuous investigation of water resources is essential to assess pollution risks. This study investigated a groundwater assessment in the coastal belt of Tamil Nadu’s Kovilpatti Taluk, Thoothukudi district. Twenty-one groundwater samples were collected during the pre-monsoon and post-monsoon seasons, analyzing water quality parameters, namely pH, EC, Cl−, SO42−, Ca2+, Mg2+, HCO3−, TH, Na2+, and K+. The Water Quality Index (WQI) was computed and it is observed that 5% of pre-monsoon and 9% of post-monsoon samples were unsuitable for drinking. SAR, MHR, RSC, %Na and Kelley’s index were used to determine irrigation suitability. Pre-monsoon shows 29% (MHR) and 71% (RSC) unsuitable, and post-monsoon shows 59% (MHR) and 9% (RSC) unsuitable. Coastal activity, urbanization, and industrialization in Kovilpatti resulted in the degradation of groundwater quality. Solving this coastal issue requires sustainable wastewater treatment and strict industrial discharge guidelines. Spatial distribution plots, Box plots, Gibbs plots, Piper plots, Wilcox plots and Correlation Matrices had similar results to the computed WQI and its physical–chemical parameters. According to the human health risk assessment, the Mooppanpatti, Illuppaiurani, and Vijayapuri regions show high health risks due to the nitrate and fluoride concentration in the groundwater. Kadambu, Melparaipatti, Therkuilandhaikulam, and Vadakku Vandanam have low levels, posing a minimal health risk.

Light-absorbing properties of polar- and non-polar brown carbon fractions of aerosols in Delhi

In the present study, PM2.5 samples (n = 104) were collected during February 2020–March 2021 on diurnal basis in Delhi (a site of Indo-Gangetic Plain (IGP)), with a view to investigate seasonal and diurnal patterns of ambient brown carbon (BrC) with consideration of their potential sources. Given that the polarity of ambient aerosol influences their chemical and physical processing in the atmosphere, we compared the light absorption properties of brown carbon (BrC) in PM2.5 samples extracted with three different solvents i.e., water, methanol, and n-hexane. Methanol extracts showed much stronger light-absorbing ability followed by water and hexane extracts in the wavelength range of 300–600 nm. Peak values of mass absorption coefficient (babs-BrC-365nm) were observed during post-monsoon season in both polar- (water-and methanol-soluble) and non-polar (n-hexane soluble) fractions of BrC, mainly due to the influence of biomass-burning (BB) aerosols. This point is further supported by air mass back trajectories which are well correlated with fire-count data, and marker species such as EC, OC and non-sea-salt K+. Comparison of babs-BrC-365nm, mass absorption efficiency (MAE365nm), absorption Ångstorm exponent (AÅE) and simple forcing efficiency (SFE300–700) from this study with that in published datasets reveal the significant contribution of biomass-burning activities to BrC absorption and abundance in the ambient atmosphere. Furthermore, the optical properties of HULIS (humic-like substances) (n = 40, during day- and nighttime) in post-monsoon (October – November 2020) and winter aerosols (January – February 2021) were also characterised. Based on UV–Vis analysis, similar average babs-365nm of HULIS was observed for daytime and nighttime samples i.e., 9.96 ± 3.8 and 9.89 ± 3.3 Mm−1, respectively in post-monsoon samples. Opposingly in winter period, significantly high daytime value of babs-365nm of HULIS (7.24 ± 2.7 M m−1) compared to that of nighttime (4.45 ± 2.8 M m−1) was found. These results along with indicative E2/E3 (ratio of absorbance at 250 nm and 365 nm, respectively) and AÅE values in HULIS fraction suggest a more significant contribution from regional crop-residue burning emission in the formation of HULIS in post-monsoon. While in winter period local emissions and subsequent secondary formation of HULIS are important. To the best of our knowledge, this study is the first attempt to investigate light absorption properties of different polarity BrC extracts (methanol, water, n-hexane, HULIS) in aerosol samples collected throughout the year at a representative site in Indo-Gangetic Plain (IGP).

The effects of anthropogenic disturbance and seasonality on the ant communities of Lang Tengah Island.

Anthropogenic disturbances and seasonal changes significantly impact diversity and community composition of ants, but their effects are often intertwined. We investigated these drivers on Lang Tengah Island, a location with a pronounced monsoon season and three resorts that close during this period. We surveyed four sites, two disturbed and two undisturbed, before and after the monsoon season, using pitfall traps to sample epigaeic ant communities. Undisturbed habitats had higher species diversity, but both habitats (undisturbed and disturbed sites) have a high proportion of ants with characteristics of being encroached by generalist and invasive/tramp ant species. Post-monsoon sampling yielded an increase in species richness and diversity. Seasonal changes, such as monsoonal rains, can temporarily alter ant interactions and resource distribution, potentially maintaining diversity. Future studies should validate these findings for ant communities under similar pressures, using ant composition and functional roles for conservation and management purposes.

Spatiotemporal distribution of microplastics in Miri coastal area, NW Borneo: inference from a periodical observation

The current study aims to investigate the spatiotemporal distribution of microplastics (MPs) in the Miri coast, targeting their occurrences, characterisation, and potential sources. For a periodical study, coastal sediments were collected from three different time intervals (monsoon, post-monsoon, and post-COVID) and subjected to stereomicroscope, ATR-FTIR, and SEM-EDX analyses. These results show a significant increase of MPs in post-COVID samples by approximately 218% and 148% comparatively with monsoon and post-monsoon samples, respectively. The highest concentration of MPs was detected near the river mouths and industrial areas where the waste discharge rate and anthropogenic activities dominate. Fibre-type MPs are the most abundant, with an average of nearly 64%, followed by fragments, films, microbeads, and foams. The most dominant polymer types were polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyester (PET). Overall, the current study shows a better understanding of MPs occurrence and potential sources in the Miri coastal area.

Feeding ecology of the pandalid shrimp, Plesionika semilaevis (Spence Bate 1888) in South Eastern Arabian Sea

The feeding ecology of deep-sea crustaceans is crucial in understanding the ecological roles and interactions of deep-sea organisms as they play a critical role in deep-sea food webs as intermediate trophic level organisms. This study provides the first examination of the feeding ecology of deep-sea shrimp Plesionika semilaevis (Spence Bate 1888) and provides new insights into deep-sea community structure. An aggregate number of 2213 individuals (842 males, 1016 berried and 355 non-berried females) were collected from the South Eastern Arabian Sea from 2019 to 2022 and their feeding ecology was studied in relation to the environmental (season) and biological (maturity, sex and size) factors. The index of preponderance values indicates the species has a diversified diet with a wide trophic niche ranging from smaller foraminifera to larger crustaceans and fishes. Frequency of occurrence (FOC) reveals that crustaceans, detritus and foraminifera forms the main prey while fishes, molluscs and sponges form the secondary prey. Berried females had the highest feeding intensity compared to males and non-berried females. Among the studied groups,the percentage of full stomachs was higher during the pre-monsoon period than post-monsoon. Feeding intensity was highest for smaller individuals and decreased gradually with an increase in size. Statistical analyses (ANOVA) also confirmed the significant differences (p<0.05) in the diet composition and feeding intensity of berried and non-berried females, pre-monsoon and post-monsoon samples and, juveniles and adults. The PERMANOVA test showed that there were significant differences in diet in the interaction between sex and size (p=0.003) and between sex and season (p=0.001). The present study also suggests that the seasonal variation in feeding intensity could be attributed to oceanographic phenomena like upwelling prevailing in the South Eastern Arabian Sea.

Assessment of groundwater vulnerability using water quality index and solute transport model in Poiney sub-basin of south India.

This paper demarcated the most vulnerable regions within the Poiney sub-basin (Tamil Nadu state in India) with respect to the groundwater quality. An index-based vulnerability assessment was carried out by measuring the physico-chemical variables such as pH, electrical conductivity, total dissolved solids, magnesium, sodium, chloride, sulphate, bicarbonate and fluoride in the pre-monsoon and post-monsoon samples. Water quality index varied across the sub-basin due to differences in the water quality induced by anthropogenic activities related to land use practices and presence of industries. The MT3D engine coupled with visual MODFLOW identified that sulphate released from tanneries and leather factories is the main effluent contaminating the groundwater. Model reveals that both the flow and contaminant transport is towards southeast with maximum and minimum calculated head of 201.82mg/l and 265.92mg/l and calculated sulphate concentration of 394.40mg/l and 46.79mg/l respectively.

Hydro-chemical characterisation and quality assessment of shallow groundwater in parts of the Kathmandu Valley, Nepal

Groundwater is the main source of water for drinking and irrigation in the Kathmandu Valley of Nepal. Although quality of groundwater is crucial for public health, there is little information available. Considering this, groundwater samples were collected during the post-monsoon and winter from 35 dug wells of Lalitpur Metropolitan City located in the Kathmandu Valley. Chemical analysis of these samples has revealed alkaline nature of groundwater. Factor analysis (FA) and correlation analysis (CoA) have identified lithology, geogenic, and anthropogenic activities as the main factors governing groundwater chemistry. Cluster Analysis (CA) segregated samples into five clusters indicating difference in their hydrochemistry. The Weightage Arithmetic Water Quality Index (WAWQI) has revealed unsuitability of groundwater for drinking. Among the chemical constituents, Fe, Ca2+, Mg2+ and PO43− are found most influential. Concentration of iron, and calcium were much higher than the recommended limit for drinking water. High total coliform (TC) content in particular makes groundwater of the valley totally unsafe for drinking. While percentage of sodium (Na%), sodium adsorption ration (SAR), and salinity hazard values of the samples are found suitable, on the basis of the Permeability Index (PI), several winter and post-monsoon samples were unsuitable for irrigation. This study strongly recommends for treatment and purification of groundwater before supply and use for drinking and irrigation purposes to minimise health-risk.

COMPARATIVE PHYSICOCHEMICAL AND HEAVY METAL CONTAMINATION ANALYSIS IN LAKE WATER SAMPLES COLLECTED FROM NALLASOPARA LAKES IN PALGHAR

Nirmal and Chakreshwar lake are two important water bodies in Vasai-Virar Taluka, are the primary source of water for the nearby villages. The objective of the study was to analysis physicochemical parameters and simultaneously monitor the heavy metal content. During the study the physicochemical parameters like pH, temperature, Total hardness, TS, TDS and TSS were evaluated in pre and post monsoon samples at three different sites from each water body. t test and two way ANOVA test were performed to assess the variation in the pre and post analysis for any significant difference. It was observed that heavy metal content was found more in pond A (Nirmal), comparative to pond B (Chakreshwar) lake.

Heavy metal pollution in groundwater of urban Delhi environs: Pollution indices and health risk assessment

The excess presence of heavy metals in water resources deteriorates the quality and has a high potential for bioaccumulation and environmental contamination. The study of heavy metals in water is essential because of their integration in the food chain and the potential for sublethal effects on aquatic and human life. To understand the extent of heavy metal pollution, a total of 64 groundwater samples (32 in each pre-and post-monsoon season) were collected around the Yamuna River's flood plains in the Delhi region. In this study, pollution indices and health risk assessment methodologies were used to estimate the significant threat to humans. In examined seasons, the sequence of heavy metal content in groundwater is Fe > Mn > Zn > B > As>Ni > Pb. The heavy metal pollution index (HPI) revealed that in the pre-and post-monsoon seasons, 53% and 44% (HPI >100), of groundwater samples are at high-risk zone respectively. 53% of pre-monsoon and 56% of post-monsoon samples were found highly polluted, according to the degree of contamination (Cd). Moreover, health risk assessment shows that hazard index (HI) values for heavy metals were found significantly high (HI >1) in groundwater samples inferring increased non-cancerous risk to the local community. The results imply that continuous exposure can lead to chronic diseases in the population residing in the study region. In both carcinogenic and non-carcinogenic assessments, children's hazard index and carcinogenic risk assessment (CR) scores were found higher. As a result, compared to adults in the study region, children are more vulnerable to potential health threats. The principal component analysis (PCA) method was used to figure out the origin of heavy metals, and it was found that As, Fe, Mn, and Zn come from non-anthropogenic sources, whereas mixed sources (natural and anthropogenic) may be responsible for B, Ni, and Pb presence. The results of the study will help to develop an effective strategy for environmental assessment and monitoring to control groundwater pollution of the Delhi urban environs.

Spatial variation of Physico-chemical parameters and water quality assessment of urban ponds at Raipur, Chhattisgarh, India

Water bodies, natural or man-made, are under threat due to rapid urbanization. This research paper assesses the water quality of 20 ponds located in the vicinity of urban habitats of Raipur district, Chhattisgarh (India) using the Water Quality Index (WQI). The samples were analyzed for 16 physicochemical parameters in the post-monsoon winter season. The parameters were used to calculate WQI and the ponds were categorized accordingly for end use purposes, that is, drinking, irrigation, industrial, or unfit for use without treatment. The WQI of post-monsoon samples resulted in that 75% of the total pond water samples are in excellent condition, & 25% of the samples are unfit for various activities like drinking, irrigation, industrial & domestic. A high value of nutrients was observed in all the ponds, suggesting that the nutrient entering through surface runoff, solid waste disposal, and wastewater is entering the ponds. Our results conclude that all ponds require interventional steps to restore pond water quality and stop it from further degradation, determining which trophic state of the ponds may change in the future. The spatial monitoring of physical and chemical properties of pond water helps to predict, identify, and assess the natural condition of the urban ponds and their relation with the surrounding (environment) and helps in adopting rejuvenation measures.

Seasonal, weathering and water use controls of silicon cycling along the river flow in two contrasting basins of South India

We present the first study of river water silicon isotopic composition from two contrasting basins in South India, the east flowing Kaveri river and the west flowing Netravathi river. Both rivers originate from the Western Ghats. River water samples were collected from mainstream, tributaries and reservoirs at different locations along the river flow during dry and wet (monsoon) seasons, with an additional post-monsoon sampling in Netravathi. High rainfall in Netravathi basin and upper reaches of Kaveri induce intense weathering in the region, with superposing contribution from anthropogenic controls in downstream Kaveri. The δ30SiDSi values range from +0.42 to +1.65‰ for Netravathi river basin and + 0.32 to +2.85‰ for Kaveri river basin. Silicate weathering index (Re) shows intense weathering associated with monosiallitization (kaolinite-gibbsite formation) in Netravathi basin and relatively moderate weathering with bisiallitization (smectite-kaolinite formation) in Kaveri basin. The seasonal changes in δ30SiDSi and Re in each basin shows similar patterns, with a likely higher and heavier contribution of soil water from deeper soil profiles closer to weathering front and bedrock, associated with significant secondary mineral formation during dry season and leaching of superficial soil profiles during the high discharge periods of monsoon. We provide a theoretical framework to estimate relative contribution of silicate weathering vs. anthropogenic processes on riverine δ30SiDSi. Re is broadly correlated with δ30SiDSi and an isotopic mass balance involving the whole rock composition (excluding the stable quartz and sericite) shows that the δ30Si in river water are well explained by silicate weathering and gibbsite-kaolinite formation in the Netravathi and upper upper reaches of Kaveri. However, silicate weathering explains only partially the heavier δ30SiDSi signatures in the middle and lower reaches of the Kaveri, and the additional enrichment of about +1.06‰ can be attributed to uptake of silicon and Si-depleted return flow through irrigated agriculture in the basin. This study confirms the major control of pedoclimatic conditions on the δ30Si of rivers and provides for the first time an estimation of the impact of human activities on the silicon isotopic signature of rivers.

Evaluation of groundwater quality for irrigation water supply using multi-criteria decision-making techniques and GIS in an agroeconomic tract of Lower Ganga basin, India

Groundwater irrigation has evolved the monocropping cultivation pattern to multi-cropping, especially in many arid/semi-arid tracts globally. Irrigation practices with the groundwater of poor quality can limit the selection of the crop, reduce crop yields and degrade the soil quality. The present study has been undertaken to identify the hydrogeochemical phenomena of groundwater systems in the south-western Birbhum district, India and to analyze groundwater suitability for irrigation during the pre-and post-monsoon cycles by adopting the Irrigation Water Quality Index (IWQI) using Multivariate Factor Analysis along with some traditional methods viz. sodium adsorption ratio, sodium percentage, magnesium hazards, residual sodium bicarbonate (RSBC) and carbonate (RSC), Wilcox's and USSL diagrams, permeability index and Kelly's index. The hydrogeochemical analysis revealed that chemical weathering and evaporation are predominant in the aquifer systems. Groundwater quality reflected soil salinity, sodicity and magnesium hazards risks and water toxicity to the sensitive plants at 0–46.4% of the post-monsoon samples and 0–38.4% of the pre-monsoon samples based on the individual traditional methods whereas about 97.73–98.88% of the total area was classified as moderate to severely unsuitable for irrigation during both seasons when integrated multiple parameters using the IWQI method. Prolonged use of such groundwater for irrigation is susceptible to causing moderate to severe infiltration problems at a greater extent of the study area. The study recommends adaptation of salinity, sodicity and RSC/RSBC reduction procedures (e.g., the use of acid and gypsum amendments in the irrigation lands and through water blending) and advanced irrigation practices (viz. drips, sprinklers and micro irrigations) to prevent soil degradation and increase crops productivity. Adopting Managed Aquifer Recharge procedures as well as rainwater harvesting in the areas bearing unsuitable water quality can dilute the ionic concentrations of the groundwater facies which in turn will improve the groundwater quality for irrigation.