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Soil quality in urban areas in India is degraded due to multiple anthropogenic activities. The objectives of this work are to determine the concentration variations, toxicity, and sources of carbons, metals, and ions in the surface soil of Raipur, the industrialized capital city of Chhattisgarh state, India. High concentrations of Al, K, Ca, Ti, Fe, and elemental carbon (EC) were registered. Relatively lower concentrations of V, Cr, Mn, Ni, Cu, Zn, Sr, Ba, Pb, organic carbon (OC), and carbonate carbon (CC), as well as ions (viz. F–, Cl–, NO3–, SO42–, Na+, K+, Mg2+, and Ca2+), were also recorded. EC was found to be one of the major pollutants, although enrichment factors pointed to high contamination with SO42–, K+, Mg2+, Cr, Mn, and Pb; and extreme contamination with NO3– and Ca2+. The spatial and temporal variations, enrichment factors, toxicity, and sources of the chemical species detected in the soil are discussed. [ABSTRACT FROM AUTHOR]

Chromium is recognised as a potent water pollutant by the WHO and thus it becomes pertinent to continuously monitor chromium levels in the waterbodies. Voltammetry, an electroanalytical technique, has been utilised for the detection of hexavalent (Cr(VI)) and trivalent (Cr(III)) chromium in aqueous samples. Carbon Paste Electrode (CPE) modified using Sphingopyxis macrogoltabida SUK2c, an indigenous bacterial strain isolated from the water samples collected from Sukinda Valley, Odisha, India, was used as a working electrode in a typical three-electrode electrochemical cell. The developed biosensors were found to provide about 3.5 fold increase in cathodic peak current compared to the bare CPE for Cr(VI) ions. Using cyclic voltammetry (CV), the Lowest Limit of Detection (LLOD) of 1 × 10−4 M and 1 × 10−2 M for Cr(VI) and Cr(III) ions, respectively, were achieved with the biosensors. The LLOD was further improved to 1 × 10−9 M and 1 × 10−7 M for Cr(VI) and Cr(III) ions, respectively, adopting differential pulse cathodic stripping Vvoltammetry (DPCSV) technique employing the biosensors. The concentrations of Cr(VI) and Cr(III) ions present in water samples collected from Sukinda Valley, Odisha, India, could be determined using the biosensor. The plausible mechanisms involved in the detection of Cr(VI) and Cr(III) ions by the developed electrochemical biosensor are discussed. [ABSTRACT FROM AUTHOR]

This work is a 7-year study of monsoonal rainwater chemistry (n = 302), over mid-Brahmaputra plain during 2012 to 2018. The samples were analyzed for major chemical parameters viz. pH, electrical conductivity (EC), and ions (SO42−, NO3−, Br−, Cl−, F−, Mg2+, Ca2+, K+, NH4+, Na+, and Li+) to assess the chemistry. The mean pH of rainwater varied among the years, which was maximum in 2018 (6.18 ± 0.72) and minimum in the year 2014 (5.39 ± 0.54), and the variations were significant at p < 0.0001. Ridgeline plots were drawn to visualize interannual variations, which revealed that Ca2+ was the dominant cation in the early years, whereas NH4+ prevailed in the latter years. Mann–Kendall analysis and Sen's slope statistical tests were employed, and it was found that all the ions showed positive S values indicating increasing trends. Enrichment factors (EF) of K+, SO42−, and NO3− were found to be high with respect to both soil and seawater suggesting the influence of emissions from fossil fuel and biomass burning in the chemistry of rainwater. Principal component analysis (PCA) was applied to identify the sources of rain constituents, and five factors were obtained explaining crustal dust, biomass burning, fossil fuel combustion, agricultural emissions, and coal burning as possible sources. Airmass back trajectory clusters and Potential Source Contribution Function (PSCF) were computed by application of HYbrid Single-Particle Lagrangian Integrated Trajectory model to appreciate the terrestrial influence on the chemistry. The results indicated inputs from both local and regional dust and anthropogenic constituents that influenced the monsoonal rainwater chemistry over Brahmaputra Valley. [ABSTRACT FROM AUTHOR]

India–Southeast Asia defence cooperation has not been highlighted much, primarily to not give out wrong signals about India's power projection outlook. With India steadfastly maintaining that it is a benign nation and not a revisionist power, engagement in the defence domain with Association of Southeast Asian Nations (ASEAN) has been attempted in five ways. The first includes India's engagement in ASEAN defence mechanisms, such as ASEAN Defence Ministers' Meeting (ADMM) Plus; and the participation of ASEAN nations in the Milan series of biennial meetings and Indian Ocean Naval Symposium (IONS). The second dimension is India's legitimate interest in the security of the Malacca Strait as a funnel state. The third dimension is developing synergies between the defence industries in Southeast Asia with the Indian defence industrial complex. The fourth angle of engagement is India's position as the net security provider in the Indian Ocean Region (IOR). The fifth critical aspect is developing maritime cooperative mechanism and developing a counter to the Chinese "string of pearls" strategy. [ABSTRACT FROM AUTHOR]

Chromite ore processing residues (COPR) are real environmental threats, leading to CrO42-, i.e., Cr (VI) leaching into groundwater. It is of serious concern as Cr (VI) is proven to be carcinogenic. Here we emphasize the application of novel and eco-friendly chitin functionalized iron-enriched hydroxyapatite nanocomposite (HAP-Fe0-Ct) in the remediation of Cr (VI)-contaminated groundwater samples collected from Khan Chandpur, India, where the level of Cr (VI) is found to be 11.7 mg/L in a complex aqueous matrix having 793 mg/L of total dissolved solids. Chitin functionality in the composite has resulted in positive zeta potential at circum-neutral pH, favoring electrostatic attraction of chromate ions and resulting in its bulk surface transport. The HAP-Fe0-Ct showed faster kinetics of removal with efficiency (qm = 13.9 ± 0.46 mg/g) for Cr (VI). The composite has shown sorption equilibrium and 100% removal of Cr (VI) within 3 h of interaction time in groundwater samples. No Cr (VI) leaching in the acid wash process at pH 3.5 also suggests chromium's strong chemisorption onto nanocomposite. During the interaction in aqueous solutions, the reduced iron (Fe0) on the nanocomposite becomes oxidized, suggesting the probable simultaneous reduction of Cr (VI) and its co-precipitation. Continuous column extraction of chromate ions was also efficient in both spiked solutions (39.7 ± 0.04 mg/g) and COPR contaminated water (13.2 ± 0.09 mg/g). Reusability up to three cycles with almost complete Cr (VI) removal may be attributed to surface protonation, new binding sites generation, and electron transfer from Fe0 core through defects. The study concludes that HAP-Fe0-Ct could be utilized for continuous Cr (VI) removal from COPR contaminated complex groundwater matrices. [ABSTRACT FROM AUTHOR]

Nuclear-spent fuel reprocessing and high-level liquid waste (HLLW) storage containers possess various inorganic higher valance oxidizing metallic ions and fission products, further influencing nitric acid corrosion through the PUREX route. This study evaluated the effect of nitric acid corrosion on gas-tungsten arc weldment (GTAW) of stainless steel (SS) 304 L in simulated reprocessing and HLLW medium in non-radioactive conditions. The effect of oxidizing metallic cations, which were present as the major amount in the mark-I spent fuel of fast breeder test reactors (FBTR) in India; these are Cs+1, Nd+3, Mo+6, Fe+3, and V+5 as a surrogate redox system for Pu(VI)/Pu(IV) and Np(VI)/Np(V) system was evaluated by the electrochemical corrosion test method in 2 M, 6 M, and 8 M nitric acid solutions. The resistance of polarization (Rp) value decreases with the nitric acid concentration, and the effect of oxidizing ions in different nitric acid concentrations also changes. The three-phase corrosion (boiling liquid, vapor, and condensate phase) resistance behavior in different concentrations (6 M and 8 M) of the nitric acid medium, without and with redox ions, has been evaluated. The corrosion rate is higher in the liquid phase compared to the vapor and condensate phases. On the other hand, it is relatively higher for the inorganic metallic redox ions containing solutions. [Display omitted] • Corrosion of the GTAW SS 304 L was evaluated in nonradioactive PUREX and HLLW medium. • Increase in nitric acid concentration, trans-passive corrosion tendency increases. • Corrosion by the metallic ion depends on its effective redox potential in the medium. • The weldment material is more corrosion-resistant than its base metal counterpart. • The descending trend of the three-phase corrosion is that liquid > vapor > condensate. [ABSTRACT FROM AUTHOR]

Present study aims to understand the hydrochemical changes in proglacial meltwater stream emerging from the termini of Dokriani Glacier, central Himalaya, India. The major ion concentration of melt water between the years 1994–2015 has been reassessed to infer the glacial/subglacial weathering induced ionic release from Dokriani glacier system. The results from meltwater data collected during post-monsoon period (October 2015) shows that Ca2+ is more dominant cation followed by Mg2+, K+, Na+ and SO42− is most dominant anion followed by HCO3− and Cl−. Scatter plot between Ca2+ + Mg2+ vs total cations shows the overall dominance of carbonate weathering whereas Na++K+ vs total anions shows high positive relation suggesting domination of both carbonate and silicate weathering. By comparison, the ionic concentration for the year 2015 suggests a significant increase since 1994; however, the discharge weighted concentrations could provide more detailed estimates. An increasing trend in major cations viz. calcium (Ca2+) and magnesium (Mg2+) while the bicarbonate (HCO3−), sulphate (SO42−) and nitrogen (NO3−) has been observed as major anion. Further, the source of Cl−, NH4+, and NO3− in the meltwater stream is mainly derived from the atmospheric precipitation, anthropogenic, and weathering process. The process of carbonate weathering and dissolution of rock is ascertained as the one which regulates the melt water chemistry. [ABSTRACT FROM AUTHOR]

Cellulose nanofibrils (CNF) were extracted from rice straw, a waste lignocellulosic biomass, using soda cooking, which resulted in a reduction of the recalcitrance of biomass, leading to hydrolysis of hemicellulose into sugars, which was subsequently washed, leaving a residue of cellulose. FTIR confirmed the removal of lignin and hemicellulose to yield pure CNF while XRD, DTG and TGA results showed increased crystallinity and thus higher thermal stability. CNFs were functionalized using l-methionine, a natural amino acid, to graft sulfides and amino functional groups onto the surface of fibers. Structural and morphological changes induced by grafting were confirmed by FTIR, XRD, TEM, Mapping and Elemental analysis. Modified fibers exhibited a high adsorption capacity of 131.86 mg/g for Hg (II) ions even at low concentration i.e. 300 ppm owing to sulfides. Optimization of pH on adsorption behavior was established through extensive pH studies and adsorption kinetics. Adsorption follows pseudo second order kinetic model indicating chemisorption for removal of Hg (II) ions from simulated wastewater. Unlabelled Image • CNFs were extracted from rice straw, a growing menace in Northern India due to its burning on field. • A natural amino acid, methionine, was utilized to functionalize CNFs. • Thorough characterization techniques FTIR, XRD, FESEM, TEM, DTG and TGA were used. • Functionalized CNFs showed good affinity for Hg (II) ions in aqueous medium. • Process parameters were established by kinetics and adsorption Isotherms studies. [ABSTRACT FROM AUTHOR]

The effect of the rocket exhaust products on the D-region of the ionosphere is investigated with the help of Very low frequency (VLF) electromagnetic wave propagation characteristics within the Earth-ionosphere waveguide. The changes in the electron density profile are computed from the observed VLF signal amplitude perturbations about 3 dB during the rocket launch. We find a localized electron depletion in the lower ionosphere at an altitude of around 58 km, that is thought to be originated by the attachment of ionospheric ion and molecular hydrogen along with water molecule in the exhaust product of first stage burn of Geosynchronous Launch Vehicle (GSLV) rocket at the time of GSLV launched from Sriharikota, India, on 27 August 2015 at 11:22 UT (16:52 IST). The ionospheric depletion perturbed the navigational VLF signal (VTX = 17 kHz) 134 s after the launch of the GSLV rocket. [ABSTRACT FROM AUTHOR]

This study attempts to examine the morphological, elemental and physical characteristics of PM 10 over the Indian Himalayan Region (IHR) using FTIR and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis. The study aimed at source identification of PM 10 by exploring the inorganic ions, organic functional groups, morphology and elemental characteristics. The pollution load of PM 10 was estimated as 63 ± 22 μg m -3 ; 53 ± 16 μg m -3 ; 67 ± 26 μg m -3 and 55 ± 11 μg m -3 over Mohal-Kullu, Almora, Nainital and Darjeeling, respectively. ATR-FTIR spectrum analysis revealed the existence of inorganic ions (SiO 4 4- , TiO 2 , SO 4 2- , SO 3 - , NO 3 - , NO 2 - , CO 3 2- , HCO 3 - , NH 4 + ) and organic functional groups (C-C, C-H, C=C, C≡C, C=O, N-H, C≡N, C=N, O-H, cyclic rings, aromatic compounds and some heterogeneous groups) in PM 10 which may arise from geogenic, biogenic and anthropogenic sources. The morphological and elemental characterization was performed by SEM-EDX, inferring for geogenic origin (Al, Na, K, Ca, Mg and Fe) due to the presence of different morphologies (irregular, spherical, cluster, sheet-like solid deposition and columnar). In contrast, particles having biogenic and anthropogenic origins (K, S and Ba) have primarily spherical with few irregular particles at all the study sites. Also, the statistical analysis ANOVA depicts that among all the detected elements, Na, Al, Si, S and K are site-specific in nature as their mean of aw% significantly varied for all the sites. The trajectory analysis revealed that the Uttarakhand, Jammu and Kashmir, the Thar Desert, Himachal Pradesh, Pakistan, Afghanistan, Nepal, Sikkim, the Indo-Gangetic Plain (IGP) and the Bay of Bengal (BoB) contribute to the increased loading of atmospheric pollutants in various locations within the IHR., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

[Display omitted] • Disulphide bonds affixed on CNF backbone ensued high selectivity for Hg(II) and SO. • Soft-soft interactions led to high selectivity and good adsorption of 828.5 mg g−1. • Rapid and nearly complete removal of Hg(II) was achieved in 8 min at 100 mg L−1. • Concomitantly, affinity for SO with 81.92% removal at 25 mgL-1 endorsed versatility. • Excellent recyclability after 8 cycles affirmed potential in wastewater remediation. Hemp stalks, readily available bio-waste in northern India, are good source of cellulose nanofibers (CNFs) with exceptional strength and stiffness. In this study, a facile route was envisaged to affix disulphide linkages on hemp derived CNFs (CNF-S-S-CNF) using 3,3-dithiopropionic acid. CNF-S-S-CNF with two sulphur groups on the cellulose backbone scored high selectivity for mercury ions (distribution coefficient of 5 × 105 mL.g−1) owing to soft–soft interactions, besides exhibiting affinity for safranin O (SO) due to strong electrostatic attractions. Thermal stability up to 700 °C advocated high temperature applications of CNF-S-S-CNF. Response surface methodology (RSM) with Box Behnken Design (BBD) was applied using Design Expert software 13 for tuning the process parameters. Statistical analysis of variance (ANOVA) established a maximum adsorption capacity, q e of 100% for Hg(II) ions achieved at optimum conditions of pH 5.5, Hg(II) concentration of 100 mg L-1 with adsorbent dosage of 100 mg and contact time of 9.50 min, while for SO, 100% adsorption was achieved at pH 6.5, SO concentration of 1 mg L-1 with adsorbent dosage of 60 mg and contact time of 9.50 min, in accord with the experimental results. Both, linear and non-linear kinetics and isotherm models were fitted to further understand the adsorption mechanism. The non-linear pseudo-second order demonstrated better adsorption kinetics for Hg(II), while SO fitted better to the linear pseudo-second order model. Ultra-rapid adsorption kinetics was achieved with pseudo second order rate constant, K 2 of 0.197 g.mg −1.min−1 and 100% removal within 5 s (Co = 10 mg L-1) of Hg(II) ions. FTIR and XPS confirmed strong interactions of CNF-S-S-CNF with Hg(II) ions accomplishing a maximum adsorption capacity, q e exp of 828.5 mg/g. Regeneration of adsorbent for 8 cycles with retention of 96% and 80% efficacy for Hg(II) ions and SO, respectively endorse its outstanding potential in waste-water remediation. [ABSTRACT FROM AUTHOR]

The current study aimed to enhance exopolysaccharide production by Klebsiella variicolaSMHMZ46 isolated from the Zawar mines area in Udaipur, Rajasthan, India, by optimizing the medium with OFAT and a central composite design. The trial including sucrose (9.5%), casein hydrolysate (3%), and NaCl (0.5%) yielded the maximum EPS production as indicated by applying the CCD-RSM biostatistical program. The composition of exopolysaccharides produced by Klebsiella variicolaSMHMZ46 culture was characterized. Growth under Pb(II), Cd(II), and Ni(II) metal amended conditions induced EPS production relative to control. TLC was used for identifying the sugar residues of EPS, in addition to determination of both total carbohydrate and protein contents. According to FT-IR analysis, EPS can interact with metal ions via their functional chemical groups, thereby supporting their bioremediation potential. The metal removal efficiency of bacteria and their produced EPS in broth individually spiked with Pb(II), Ni(II), and Cd(II) was 99.18%, 97.60%, and 98.20%, respectively, and powdered EPS from contaminated water was 85.76%, 72.40%, and 71.53%, respectively. According to FEG-SEM observations, the surface morphology of EPS becomes rough, demonstrating sharp bumps after metal binding. A FEG-SEM analysis of the structure of EPS was performed; the surface structure of EPS (with metal) was more rigid than that of control EPS (without metal). The interaction between the EPS system and Pb(II) ions was investigated using FEG-SEM coupled with energy dispersive X-ray spectra, and a strong peak of C, O, and Pb elements was observed, indicating successful Pb adsorption. These findings suggest that EPS from Klebsiella variicolaSMHMZ46 has a good metal adsorbing nature and could be a promising biosorbent for metal bioremediation of contaminated water., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Submarine groundwater discharge (SGD) and Saline water intrusion (SWI) are the two major processes that influence coastal aquifers resulting in severe water stress. It is essential to characterize groundwater dynamics and discriminate geochemical characterization to understand both approaches. The present study investigates the zones influenced by SGD and SWI along the coastal aquifers of Tamil Nadu and Pondicherry. Pore water (PW) and groundwater (GW) samples were collected during the monsoon season at low tide and analyzed for major ions adopting standard procedures. Hydrogeochemical characterization of water samples revealed by the piper, ionic ratio, ionic delta (Δm i ), and seawater fraction (f Sea ) plots suggest that the PW samples, irrespective of location and GW samples in specific areas, were attributed to SWI, while the remaining samples suggested SGD. The average chloride-attributed SGD flux calculated for PW was 23.45 × 10 -7  L cm -2 S -1 and for GW, 0.58 × 10 -7  L cm - S -1 . Higher fluxes observed in PW suggest seawater recirculation as the primary mechanism, and GW samples were found to be influenced by fresh, recirculated, and saline intrusions. Overall, the northern parts of the study region were influenced by freshwater discharge. However, the central and southern parts of the study regions were influenced by mixed RSGD and SWI water types. The present work suggests locations influenced by fresh, recirculated, and saline water zones that can benefit the stakeholders in planning strategies to identify proper aquifer recharge and suggest ideal pumping scenarios to sustain groundwater resources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Groundwater samples were collected from 44 wells in the Ramganga Sub-Basin (RSB), India, and analysed for major ions, nutrients and trace metals. The primary goal of this study is to evaluate the hydrochemistry and to identify the geochemical processes that govern the water chemistry in the shallow and deep tube wells in the study area using geochemical methods. The knowledge of changes in hydrochemistry of the aquifers is important for both groundwater recharge and use in the region. This study found that there are substantial differences of water chemistry between shallow and deep wells. In the shallow wells, the average concentrations of total dissolved solid (TDS), Na, K, Ca, Mg, HCO, Cl, SO, NO, PO, F, Cu, Mn, Fe and Cr are twofold higher than the deep wells. The concentrations of dissolved silica in the groundwater do not vary with the depth, which implies that the variation in the water chemistry is not due to mineral dissolution alone. Major ion ratios and saturation indices suggest that the water chemistry is predominantly controlled by dissolution of carbonate minerals, silicate weathering and ion exchange reactions. Thermodynamic evaluation (ion activity ratios and stability filed diagrams) indicates that the kaolinite and gibbsite controlled the water chemistry in the both shallow and deep wells. In addition, the groundwater chemistry in the shallow wells is affected by the vertical infiltration of contaminated water from surface contamination sources and nitrification process. In the deep wells, absence of NO and low concentrations of Cl, SO, PO and F imply the role of regional flow and denitrification in the groundwater. Results concluded that proper management plan is necessary to protect the shallow aquifer in the RSB since shallow aquifer pumping is less expensive than the deeper one. [ABSTRACT FROM AUTHOR]

Twelve hour integrated ambient fine particles (PM 2.5 ) were collected over an Van Vihar National Park (VVNP), in Bhopal, Central India. Samples were collected on filter substrates every-other-day for two years (2012 and 2013). In addition to PM 2.5 mass concentration, water soluble inorganic ions (WSIIs) were also measured. Further, on-site meteorological parameters including temperature, wind speed, wind direction, relative humidity, rainfall and atmospheric pressure were recorded. During 2012, the average PM 2.5 concentration was 40 ± 31 μgm −3 while during 2013 it was 48 ± 50 μgm −3 . Further, in about 20% of the samples the 12 h integrated fine PM mass exceeded the daily (24 h) average standards (60 μgm −3 ). This observation suggests that the PM 2.5 mass concentration at the study site is likely to be in violation of the National Ambient Air Quality Standard (NAAQS), India. During the study period the sum of three major ions (SO 4 2− , NO 3 − , and NH 4 + ) accounted for 19.4% of PM 2.5 mass on average. Air parcel back trajectory ensembles revealed that emissions from thermal power plants were likely to be the main regional source of particulate SO 4 2− and NO 3 − measured over VVNP. Further, local traffic activities appeared to have no significant impact on the concentrations of PM 2.5 and its WSIIs constituents, as revealed by a day-of-the-week analysis. PM 2.5 mass, SO 4 2− , NO 3 − , and NH 4 + showed a pronounced seasonal trend with winter (Jan, Feb) and post-monsoon (Oct, Nov, Dec) highs and pre-monsoon (Mar, Apr, May) and monsoon (Jun, Jul, Aug, Sep) lows, during both 2012 and 2013. Further, when the sum of SO 4 2− and NO 3 − constituted greater than 90% of water soluble inorganic anions by mass, they were linearly dependent on one another and moderately anti-correlated (r 2 = 0.60). The molar ratios of NH 4 + and non-sea salt SO 4 2− were examined to understand the aerosol neutralization mechanisms and particulate NO 3 − formation. An assessment of these ratios and subsequent analyses suggested that in NH 4 + rich samples, NO 3 − and non-sea salt SO 4 2− were almost entirely neutralized by NH 4 + . In NH 4 + poor samples, in addition to NH 4 + non-sea salt K + played a role in acidity neutralization. These observations are unlike those reported for PM 10 and total suspended particles (TSP) over other locations in India, where mineral aerosol species (specifically Ca 2+ ) played an important role in neutralizing acidic species. Additionally, both during 2012 and 2013, the aerosol acidity showed a pronounced seasonality - the aerosol was alkaline or near-neutral during the winter and post-monsoon seasons, while during the pre-monsoon and monsoon seasons it was acidic. [ABSTRACT FROM AUTHOR]

This study addresses the three major questions: (1) what are the emission sources of PM 1 which are affecting the study area; (2) where do these emission sources come from; and (3) is there any temporal variation in the emission sources. To address these issues, two advanced statistical methods are described in this paper. Identification of emission sources was performed by EPA PMF (v 5.0) and to understand the temporal variability, sampling was done for three winter seasons 2008–09, 2009–10 and 2011–12 within Kanpur city. To identify the possible source directions, Conditional Bivariate Probability function (CBPF) was used. The average PM 1 concentration was higher in 2008–09 followed by 2011–12 and 2009–10 winter seasons. 2008–09 winter showed sources such as secondary sources mixed with power plant emission (42.8%), industrial emission (32.3%), coal combustion, brick kilns and vehicular emission (13.2%) and residual oil combustion and road dust (11.7%). The major contributors during winter season 2009–10 were secondary sources (33.1%), biomass burning (23.3%), heavy oil combustion (13%), vehicular emission mixed with crustal dust (11.3%), leather tanning industries (10.3%), industrial emission (4%), coal combustion and brick kilns (3.4%) and solid waste burning and incineration (1.5%) compared to secondary sources mixed with biomass burning (42.3%), industrial emission and crustal dust (35.1%) and vehicular emission and brick kilns (22.6%) during 2011–12 winter season. PMF model revealed that secondary sources were the main contributors for all the three winter seasons followed by biomass burning and power plant emission. The results of CBPF analysis agreed well with the locations of known local point sources., e.g. in the case of industrial emissions, the maximum probability was in the direction between NES direction where almost all the major industries are located in and around Kanpur while in the opposite direction the probability of biomass burning was high due to a rural area in NWS direction. [ABSTRACT FROM AUTHOR]

Urban air pollution is a growing menace leading to human discomfort, increased hospitalizations, morbidity, and mortality. This study deals with deteriorated air quality due to firecracker bursting during Diwali in Lucknow. Inhalable particulates and gaseous pollutants were monitored during Diwali 2020 using air samplers. Elements, ions, and surface morphology of particles were analyzed using ICP-MS, ion chromatograph, and SEM-EDX, respectively. PM 10 , PM 2.5 , SO 2 , and NO 2 were 558, 352, 44, and 86 μg/m 3 during Diwali night and 233, 101, 17, and 40 μg/m 3 on pre-Diwali night while 241, 122, 24, and 43 μg/m 3 on Diwali day. Concentrations surged for PM 10 : 139% and 132%, PM 2.5 : 249% and 189%, SO 2 : 159% and 83%, and NO 2 : 115% and 100% on Diwali night compared to pre-Diwali night and corresponding Diwali day, respectively. Al, K, Ba, and B showed dominance in PM 10 whereas Zn, Al, Ba, and K in PM 2.5 on Diwali night. The order of metal abundance in PM 2.5 was Cd < Co < Ag < As < Cr < Ni < Cu < Bi < Pb < Mn < Sr < Fe < B < Zn < Al < Ba < K. Cations NH 4 + , K + , Mg 2+ , Ca 2+ , and anions F - , Cl - , NO 3 - , Br - , NO 2 - , SO 4 -2 , PO 4 3- showed a 2-8 fold increase on Diwali night relative to pre-Diwali night. Average metal concentrations varied by 2.2, 1.6, and 0.09 times on Diwali than pre-Diwali in residential, commercial, and industrial areas, respectively. PM 10 concentration increased by 458% and 1140% while PM 2.5 , 487%, and 2247% than respective NAAQS and WHO standards. Tiny firecracker particles vary in toxicity as compared to vehicular emissions and have enhanced bioavailability leading to severe threat in terms of LRI, COPD, and atherosclerosis for city dwellers. It is imperative to recognize the present status of ambient air quality and implement regulatory strategies for emission reduction., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

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The paper discusses the ionic sources and chemical quality of the waters (surface and groundwater) around the Tehri reservoir in Uttarakhand, Garhwal, Himalaya, for drinking and irrigation purposes. The main Bhagirathi river, tributary streams and springs and groundwater are the main sources of water for the reservoir and inhabitant living around it. Fifty-two water samples were collected from springs, handpumps (borewell) and streams and were analysed for major ions. The pH is varying from 6.8 to 8.6 and EC from 28 to 820 μS/cm. The chemical composition of water is dominated by Ca, Mg and HCO. The high ratio of Ca + Mg /Na + K and low ratio of Na + K/TZ indicate dominance of carbonate dissolution as the main solute acquisition process in this part of Lesser Himalaya. The trilinear and X-Y plots suggest less contribution from silicate weathering and anthropogenic activities. The excess of Na over Cl indicating much of the alkalis in the waters of Tehri area have source other than precipitation possibly from silicate weathering. Recharged by meteoric water, the quality of water in the study area is controlled essentially by chemical processes occurring between water and lithology and locally altered by human activities. Among the trace metals the concentration of Fe at few locations has marginally exceeded the WHO and BIS standards of drinking water. The analytical result computed from various water quality indices indicate fairly good quality of water for both drinking and irrigation purposes. The factor analysis performed on the major ion data indicate two factors are the most important affecting the water quality of the area. [ABSTRACT FROM AUTHOR]

The lower reaches of the Sabarmati River Basin in Gujarat have intense agricultural and industrial activities and this part is affected by problems of groundwater salinity. Here we attempt to assess the processes governing the causes of groundwater salinity in the coastal alluvial aquifer, employing δ 18O and δ D isotopes in integration with ionic ratio. The different hydrochemical facies such Na-Mg-HCO3-Cl, Na-Cl-SO4, Na-Mg-Cl-HCO3-SO4 and Na-Cl of groundwater show the occurrence of complex geochemical phenomenon in the study area. Ionic ratio (such as Mg2+/Ca2+, Na+/Cl-, SO42-/Cl-, K+/Cl-) and isotopic composition (δ 18O and δ D) of groundwater indicate that while in coastal areas seawater intrusion is taking place, in inland areas various anthropogenic activities and overexploitation have induced salinity in groundwater. Over-pumping of groundwater has also induced lateral intermixing of highly saline water in the vicinity of coastal areas with relatively fresh/low saline groundwater along specific flow pathways. [ABSTRACT FROM AUTHOR]

In the present study, the observation of indoor air ion concentration at a rural site has been carried out for the first time. These indoor observations are compared with outdoor air ion concentration. Net charge can be introduced into the atmosphere by processes such as combustion, rainfall and ultraviolet radiation. As compared to indoors, average air ions of both the polarities at outdoors are higher. Moreover, the air ion concentrations, experience large fluctuations during daytime, as compared to nighttime values. Positive and negative air ion concentrations are lower and uniform throughout the night both for indoor and outdoor conditions. Pollution index is more or less unity for outdoors in all-the-time period, which is good for human health. Due to limited sources of air ions indoors, it is observed that pollution index decreases from 00:00-02:00 hours and minimum is reached during 12:00-14:00 hours for indoors. During 00:00-02:00 hours, the indoor pollution index is 1.55, which is very harmful to human health. [ABSTRACT FROM AUTHOR]

The PM and PM samples were collected during Diwali celebration from study area and characterized for ionic concentration of four anions (NO, NO, Cl, SO) and five cations (K, Mg, NH, Ca, Na). The results showed that the ionic concentrations were three times compared to those on pre and post Diwali days. Predominant ions for PM were K 33.7 μg/m, Mg 31.6 μg/m, SO 22.1 μg/m, NH 17.5 μg/m and NO 18 μg/m and for PM the ionic concentrations were Mg 29.6 μg/m, K 26 μg/m, SO 19.9 μg/m, NH 16.8 μg/m and NO 16 μg/m. While concentration of SO and NO were 17.23, 70.33 μg/m respectively. [ABSTRACT FROM AUTHOR]

The present study has been carried out to assess groundwater quality in parts of Hindon-Yamuna interfluve region of western Uttar Pradesh. Fifty-five groundwater samples were collected from hand pumps in post-monsoon 2005 and pre-monsoon 2006 period, respectively, covering an area of about 1,345 km. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solid, Na, K, Ca, Mg, HCO, Cl, and SO were determined. Concentration of the chemical constituents in groundwater of the study area varies spatially and temporarily. Interpretation of analytical data of major ion chemistry helps to identify three chemical types of groundwater i.e. 'mixed', 'mixed bicarbonate' and 'alkali bicarbonate' types. The species likely to occur in groundwater of the study area are Ca-HCO, Mg-HCO, Ca-SO, Na-Cl, Na-SO, Na-HCO, K-Cl, and some other possible species of K, depending on its abundance. The groundwater of the study area comes under the category of moderately hard to very hard, mildly acidic to slightly alkaline in nature. There is anomalously high concentration of major ions, particularly, Na, K, SO, and Cl. High SO and K values may be related to anthropogenic influences, rather than through some natural process. Sodium along with Cl may be added to the system through sewage pollution and leachate percolation. [ABSTRACT FROM AUTHOR]

Nagpur City located in semiarid area of central India is a fast-growing industrial centre. In recent years, rapid development has created an increased demand for drinking water, which is increasingly being fulfilled by groundwater abstraction. The present study was undertaken to assess major ion chemistry of shallow groundwater to understand geochemical evolution of groundwater and water quality for promoting sustainable development and effective management of groundwater resources. A total of 47 water samples were collected from shallow aquifer of selected parts of the city and the water chemistry of various ions viz. Ca, Mg, Na, K, CO $_{3}^{\ \, 2-}$, HCO $_{3}^{\ \, -}$, Cl, SO $_{4}^{\ \,2-}$ and NO $_{3}^{\ \,-}$ are carried out. The chemical relationships in Piper diagram identify Ca-HCO-Cl and mixed Ca-Na-HCO-Cl as most prevalent water types. Alkaline earth exceeds alkalis and weak acids exceed strong acids. Ionic ratios and Gibb's diagram suggest that silicate rock weathering and anthropogenic activities are the main processes that determine the ionic composition in the study area. The nitrate appeared as a major problem of safe drinking water in this region. We recorded highest nitrate concentration, i.e., 411 mg/l in one of the dug well. A comparison of groundwater quality in relation to drinking water quality standards revealed that about half of the shallow aquifer samples are not suitable for drinking. [ABSTRACT FROM AUTHOR]

To better characterize the tropical aerosols in Indian region, PM10 samples collected from Chennai, India (13.04° N; 80.17° E) were analyzed for carbonaceous and water-soluble ionic components. Concentration ranges of elemental carbon (EC) and organic carbon (OC) were 2.4-14 µgm-3 (ave. 6.5 µgm-3) and 3.2-15.6 µgm-3 (ave. 9.1 µgm-3) in winter samples whereas they were 1.1--2.5 µgm-3 (ave. 1.6 µgm-3) and 4.1-17.6 µgm-3 (ave. 9.7 µgm-3) in summer samples, respectively. Concentration of secondary organic carbon (SOC) retrieved from EC-tracer method was 4.6±2.8 µgm-3 in winter and 4.3±2.8 µgm-3 in summer. OC accounted for 38.5±14 % (n = 49) of combined concentrations of carbonaceous and ionic components in PM10. We also found that OC concentrations are generally higher than those of SODue to image rights restrictions, multiple line equation(s) (8.8±2.5 µgm-3 and 4.1±2.7 µgm-3 in winter and summer, respectively), which was the most abundant ionic species (57%) followed by Due to image rights restrictions, multiple line equation(s) (15%) Due to image rights restrictions, multiple line equation(s) . The mass fractions of EC, organic matter (OM) and ionic species varied seasonally, following the air mass trajectories and corresponding source strength. Based on mass concentration ratios of selected components and relations of EC and OC to marker species, we found that biofuel/biomass burning is a major source of atmospheric aerosols in South and Southeast Asia. The high concentrations of SOC andWSOC/OC ratios (ave. 0.45; n=49) as well as good correlations between SOC and WSOC suggest that the secondary production of organic aerosols during long-range atmospheric transport is also significant in this region. This study provides the baseline data of carbonaceous aerosols for southern part of the Indian subcontinent. [ABSTRACT FROM AUTHOR]

The demand of water supply is increasing day by day to meet the pace of developments in domestic, agricultural and industrial sectors especially in developing countries like India. Groundwater being a scarce commodity in a hard rock terrain like Dindigul district an attempt has been made in this study brings out the significance of temporal ion chemistry in groundwater by collecting groundwater from 43 different location of the district and analysed for major and minor ions. These ions were then used for the irrigation classification of groundwater and to bring out the mechanisms responsible of the water chemistry of the region during different seasons. [ABSTRACT FROM AUTHOR]

Abstract: Suspended particulate matter (SPM) was collected by using high volume samplers (HVS) from two different locations: Bay of Bengal (BoB) and State Botanical Garden (SBG) situated in the eastern part of India. The SPM samples were collected on Whatman No.41 filter papers. The samples were simultaneously collected daily from both the locations during March 17–April 1, 2006. The average SPM concentration over BoB and SBG was found to be 39.05 and 78.14μg/m3 respectively. Na+ and SO4 2− were the most dominant water-soluble constituents over BoB and SBG respectively. The ratio of SO4 2−/NO3 − concentrations in both the cases was observed to be >1 indicating that the contribution of atmospheric acidity was more due to SO4 2− than NO3 −. From intra-correlation analysis it is found that at both the locations, Na+ and Cl− were well correlated while SO4 2−-Ca2+ and SO4 2−-NH4 + were poorly correlated indicating the later ion pairs to be derived from different sources. The Windrose diagrams for wind speed and direction show that for SBG, the wind blew from the SE and SW directions and brought in pollutants from soil and anthropogenic sources. In case of BoB, the wind parcels mostly were blown from the land mass (EES direction) showing the influence of anthropogenic pollutants on the marine aerosols. All the variables can be classified into three factors using principal component analyses technique. It explained 85% of total variance. [ABSTRACT FROM AUTHOR]

Introduction: Inorganic ion concentrations in event-based wet-only precipitation samples collected during the south-west (SW) monsoon at an urban location in Western India, Ahmedabad between July 2000 and September 2002 were measured by Rastogi and Sarin (). Methods: For the first time at a location in India, an advanced factor analysis model was retrospectively applied to the measured concentrations of ions (Rastogi and Sarin ) in precipitation for source apportionment. Positive matrix factorization resolved five factors, including crustal material, sea salt, nitrate/sulfate-rich factor, ammonium-rich factor, and free acidity. Results and discussion: Amongst the model-resolved factors, crustal material was the highest contributor to the total dissolved solids (TDS) accounting for 44.1% on average. Potential source contribution function (PSCF) analysis identified source locations along the eastern coast of Somalia, Yemen, Oman, and the United Arab Emirates for this factor. Sea salt was the second highest contributor accounting for 29.8%. The potential source regions of this factor were also identified in the Arabian Sea and the southern Indian Ocean along the coast of Africa, and the Arabian Gulf. This study also examined the spatial relationships between the source locations of chemical species in precipitation and in ambient aerosol (resolved in an earlier study). Conclusions: Crustal material was the highest contributor to TDS at the study location. Spatial relationships between aerosol and precipitation factor source regions suggested that below-cloud scavenging of aerosol particles was a likely contributor to the chemical species apportioned to various precipitation factors. Additionally, source types of chemical species in precipitation resolved in this study were qualitatively compared with those identified at other locations in India. The comparison showed that soil was an important contributor to the dissolved mass of chemical species in precipitation at all locations in India. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the concentration of acid and water-soluble ions (Na+, K+, Mg++, Ca++, F−, Cl−, NO3 − and SO4 − −) in different particle size range (>1.1–<2.0μm, >2.0–<3.3μm, >3.3–<4.7μm, >4.7–<5.8μm, >5.8–<9.0μm and >9μm–<10μm) of PM10 atmospheric aerosols collected by six stages Anderson Cascade Impactor were determined using conductivity suppressed ion-chromatography system. Suspended particulate matters in the form of respirable (PM10) aerosols were collected on the roof of a three storied building at a height of 20m above the ground, at Bhabha Atomic Research Centre (BARC), Mumbai using Hi-Volume Sampler (HVS) with Whatman glass fiber filter paper during the period of March–June 2009. The sequence of solubility of ions in both extractants (acid+water) of PM10 aerosols from greatest to least was found to be Na+ >Ca++ >K+ >Cl− >F− >Mg++ >NO3 − ≈SO4 −−. The average concentration of Na+, K+, Mg++, Ca++, F−, Cl−, NO3 − and SO4 −− in PM10 aerosols was estimated to be 13.36g/kg, 3.76g/kg,0.251g/kg,3.771g/kg,0.833g/kg,1.17g/kg, 81μg/kg and 290μg/kg respectively. The enrichment of particular ion in soluble components may be due to its high abundance in PM10 aerosols, less sorptivity with the tiny solid particles of atmospheric dust, high extractability and leachability, high solubility and mobility. By classifying the PM10 aerosols into two categories viz fine particle (<2.5μm) and coarse particle (>2.5μm–<10μm), it was found that generally, in the fine particle, the geometric mean concentration of total soluble ions in acid and water components was found to be higher than coarse particle. Overall, it was also observed that generally as particle size increases, the geometric mean concentration of soluble ions in both extractants of PM10 aerosols decreases. [Copyright &y& Elsevier]

Abstract: To investigate the potential role of ammonia in ion chemistry of PM2.5 aerosol, measurements of PM2.5 (particulate matter having aerodynamic diameter<2.5µm) along with its ionic speciation and gaseous pollutants (sulfur dioxide (SO2), nitrogen oxides (NO x ), ammonia (NH3) and nitric acid (HNO3)) were undertaken in two seasons (summer and winter) of 2007–2008 at four sampling sites in Kanpur, an urban-industrial city in the Ganga basin, India. Mean concentrations of water-soluble ions were observed in the following order (i) summer: SO4 2− (26.3µgm−3)>NO3 − (16.8)>NH4 + (15.1)>Ca2+ (4.1)>Na+ (2.4)>K+ (2.1µgm−3) and (ii) winter: SO4 2− (28.9µgm−3)>NO3 − (23.0)>NH4 + (16.4)>Ca2+(3.4)>K+(3.3)>Na+ (3.2µgm−3). The mean molar ratio of NH4 + to SO4 2− was 2.8±0.6 (mostly >2), indicated abundance of NH3 to neutralize H2SO4. The excess of NH4 + was inferred to be associated with NO3 − and Cl−. Higher sulfur conversion ratio (F s: 58%) than nitrogen conversion ratio (F n: 39%) indicated that SO4 2− was the preferred secondary species to NO3 −. The charge balance for the ion chemistry of PM2.5 revealed that compounds formed from ammonia as precursor are (NH4)2SO4, NH4NO3 and NH4Cl. This study conclusively established that while there are higher contributions of NH4 +, SO4 2− to PM2.5 in summer but for nitrates (in particulate phase), it is the winter season, which is critical because of low temperatures that drives the reaction between ammonia and HNO3 in forward direction for enhanced nitrate formation. In summary, inorganic secondary aerosol formation accounted for 30% mass of PM2.5 and any particulate control strategy should include optimal control of primary precursor gases including ammonia. [Copyright &y& Elsevier]

ABSTRACT Particulate matter (PM) levels show significant seasonal variability and this can influence the neutralization of rainwater acidity. Months were grouped in two periods: monsoon (July to October) and non-monsoon (November to June) for studying the seasonal variability in PM and rainwater composition. To clearly establish the cause effect relationship of acid rain neutralization, a two tier model was proposed involving source apportionment of particulates at two levels: (i) ambient air and (ii) rainwater particulate interaction. For modelling purpose, PM10 ( n= 100), soil ( n= 4) and rainwater ( n= 83) samples were collected at Kanpur, India during 2000-2002. The collected samples were analysed for metals and water soluble ion composition to employ factor analysis for source identification. Knowledge of statistical correlation and chemistry fundamentals were combined to estimate the sources for acid rain neutralization. NH4+ was a dominating ion responsible for neutralizing the acidity of rainwater in monsoon period and Ca2+ was dominating in non-monsoon period. Components of secondary particles (SO42− and NO3−) showed affinity with NH4+, signifying the major role that ammonia can play if present in excess of stoichiometric requirements. [ABSTRACT FROM AUTHOR]

Airborne particulate matter (PM10) was collected for a period of 1 year at six locations in Madurai city, India. The chemical analyses on PM10 samples were carried out for the estimation of heavy metals and ions using atomic absorption spectroscopy and ion chromatography respectively. The average PM10 concentrations varied from 97.2 to 152.5 μg/m3, which were found to be below the Indian air quality standards. While industrial areas had the highest concentrations of heavy metals such as Fe, Zn and Cr and also the $\text{SO}_{4}^{2-}$ ions, traffic areas with relatively higher traffic densities in the city endured highest concentrations of Cd and the $\text{NO}_{3}^{-}$ ion. As gaseous pollutants serve as precursors of ionic particles in the atmospheric environment, gaseous pollution control is necessitated along with particulate with special reference to heavy metal and ion pollution abatement for the sustainable development of Madurai city. [ABSTRACT FROM AUTHOR]

Abstract: Chemical composition of precipitation collected from a rural forest station near Bhubaneswar in the east coast of India during 2005–2007 was studied. The rainwater and dust-fall washings were collected through a wet-only collector and a bulk collector placed together and the second bulk collector located 500m apart in the same locality. NH4 + and NO3 − were observed to be the dominating cation and anion respectively. The volume weighted mean pH over three years was >5.5 indicating neutrality of collected samples. pH of <5.5 occurred in 40.8% events in the case of B1, maintaining earlier reported values (43%) compared to an all India average of negligible number. The major acidifying (NO3 − and SO4 2−: 29.3%) and neutralizing components (NH4 +, Ca2+ and H+: 26.7%) were well balanced exhibiting linear relationship. An increasing trend of NH4 + and a decline in Ca2+ were observed compared to 1995–2001. NaCl of marine origin accounted for 33.4%. Enrichment analysis showed that except for Cl− and Na+, which were of marine origin, all other ions originated from multiple sources. The fractional acidity showed proper neutralization of acid components. Correlation studies were carried out to evaluate interrelation amongst various components, which were also indicative of their common origin. Principal component analysis showed the distribution of various ions. [Copyright &y& Elsevier]

Abstract: This work focuses on size segregated atmospheric aerosol mass concentrations and water soluble inorganic components in Chhattisgarh, the eastern central India. Investigation on the monitoring of ambient air levels of atmospheric particulates were done around a large source of primary anthropogenic particulate emissions: the industrial area and coal based power plants. Chemical characterization was carried out for aerosol samples collected in urban area, Raipur, (21°14′N, 81°38′E) of Chhattisgarh region over a period of one year, using cascade impactor. Annual mean of mass concentration for coarse (PM2.5–10) and fine (PM2.5) aerosols were monitored to be 238.1±89.9 and 167.0±75.3µgm−3 respectively This work deals with the seasonal variation and meteorological influences of inorganic components of the aerosols viz. NO3 −, Cl− and SO4 2−, Mg2+, Na+, K+, Ca2+ and NH4 +. The annual mean concentration of the inorganic components were monitored to be 3.8±2.5, 8.9±2.7, 10.2±1.5, 2.6±0.6, 8.7±7.2, 4.6±1.8, 16.4±6.9 and 0.4±0.5µgm−3 respectively in coarse particles and 8.2±7.1, 6.8±3.6, 46.5±32.8, 1.7±0.6, 7.4±3.6, 5.9±3.4, 10.2±2.9, and 8.8±7.7µgm−3 respectively in fine particles, for the above ions. The average distribution of nitrate and sulphate in PM2.5–10 were found to be 1.6 and 4.2% and in PM2.5 were 4.9 and 27.9% respectively indicating the dominance of sulphate in both PM2.5–10 and PM2.5 particles. Here, industrial emission plays important role for contribution of PM2.5 particle loading in the atmosphere. The cation–anion rational analysis indicated that the PM2.5–10 particles were mostly neutralized and PM2.5 particle were acidic. The major ions were mainly in the form of NaCl>CaSO4 >K2SO4 >MgSO4 >KCl>NH4Cl>Ca(NO3)2 >KNO3 >MgCl2 >Mg(NO3)2 >NH4NO3 >(NH4)2SO4 in coarse aerosol particles and (NH4)2SO4 >K2SO4 >CaSO4 >NaCl>NH4NO3 >CaCl2 >KNO3 >MgCl2 >Ca(NO3)2 >KCl>NH4Cl in fine particles. [Copyright &y& Elsevier]

Parametric statistical approaches, correlations and multiple linear regressions were used to develop models for the interpretation of hydrogeochemical parameters in the Western part of Delhi sate, India. The hydrogeochemical parameters indicated that the groundwater quality is not safe for consumption. The water is moderately saline and the salinity level is increasing over time. There is also the problem of nitrate pollution. The correlation between electrical conductivity (EC) and other water quality parameters except potassium (K+), nitrate (NO3 −) and bicarbonate (HCO3 −) is significantly positive and Ca++ + Mg++/Na+ + K+ is significantly negative. In predicting EC, the multiple R2 values of 0.996 and 0.985 indicate that 99.6% and 98.5% variability in the observed EC could be ascribed to the combined effect of Na+, HCO3 −, Cl−, SO4 −−, NO3 − and Ca++ + Mg++ for the year of 2005 and 2006 respectively. Out of 99.6% of the variability in EC in 2005, 51.2% was due to Cl− alone, and 8.5%, 12.5%, 6.1%, 14.7% and 6.7% were due to Na+, HCO3 −, SO4 −−, NO3 − and Ca++ + Mg++. Similarly in 2006, out of 98.5% of the variability in EC, 48.5% was due to Cl− either individually or in combination with other ions and the multiple regression models can predict EC at 5% level of significance. [ABSTRACT FROM AUTHOR]+, HCO3 −, SO4 −−, NO3 − and Ca++ + Mg++. The analysis shows that a good correlation exists between EC, Cl− and SO4 −− either individually or in combination with other ions and the multiple regression models can predict EC at 5% level of significance. [ABSTRACT FROM AUTHOR]

Abstract: The dissolved concentrations of major ions and Sr isotopes (87Sr/86Sr) were measured in the headwaters of the Chambal river and its tributaries draining the Deccan Trap basalts and the Vindhyan sediments of peninsular India. The total dissolved solids (TDS) ranged from 181 to 547 mg L−1; much higher than the global “mean” river water. A significant fraction of solute abundance in the Chambal river is derived from sodium salts, unlike the Himalayan rivers which exhibit dominance of (Ca+Mg) salts. It is estimated that the Chambal river supplies about one-third of sodium via the Yamuna to the Ganga at Rajshahi (Bangladesh), with only ∼6.5% of water discharge. The presence of Na salts not associated with chloride in the Chambal headwaters constraints the application of Na⁎ (Na corrected for Cl) as an index of silicate derived component. This finding brings out the need to revisit the estimates of silicate erosion rate (SER) and associated CO2 consumption in the Ganga basin, downstream Allahabad, based on Na⁎ as an index. The Sr concentration in the Chambal tributaries varied from 1.9 µM to 5.9 µM and 87Sr/86Sr ratio from 0.70923 to 0.71219. Unlike the Himalayan Rivers, Sr isotope composition in the Chambal river is far less radiogenic as the major sources of Sr to the Chambal are the Deccan Trap basalts and the Vindhyan sediments, which are low in 87Sr/86Sr. The Sr isotope budget of the Ganga, based on available data of the Chambal, Betwa, Ken, Yamuna and the Ganga shows that, weathering of the Deccan Trap basalts and the Vindhyan sediments (the drainage basin of the Chambal, Betwa and the Ken) contribute ∼70% of the dissolved Sr to the Ganga at Varanasi. This study highlights the key role of peninsular rivers draining the Deccan and the Vindhyan regions in the major ion and Sr budget of the Ganga. [Copyright &y& Elsevier]

The influence of ionic composition on the water chemistry and thereby on aquatic flora was investigated. Two major wetlands of North India were taken for the study. Quality parameters of the lakes showed the enrichment of the water especially in the month of September with higher values of P and BOD in almost all of the lakes viz., LSJ, LCH, LSN, and LHT as <5.0, 9.0, 1.0, 1.7 and <7.3, 6.0, 6.3, and 4.0, respectively. Statistically correlated values of the ions in the water quality showed an effect of one on another. An attempt has also been made to investigate if ionic constituent is one of the major causes affecting the aquatic floral diversity. [ABSTRACT FROM AUTHOR]

Hydrochemical study had been carried out on the groundwater resources of Potharlanka Island, Krishna delta, India. Groundwater samples were collected and analyzed at 42 sites in December 2001 and October 2006. A comparative study of hydrochemical data indicates: groundwater is mildly alkaline with a pH of 7.0–8.2; electrical conductivity (EC) varies from 605 to 5,770 μS/cm in December 2001, and 652–5,310 μS/cm in October 2006. More than 62% of the groundwater samples in 2006 have TDS value <2,000 mg/l, which is within permissible limit of potable water, but 57% of the samples in 2001, are higher than the maximum permissible limit. Extremely low HCO3/Cl and variable high Mg/Ca (molar ratios) had been indicated the transformation of the fresh groundwater aquifer systems to saline in 2001. Groundwater of this Island is mainly classified as Na–Cl and mixed types. A high percentage of Na–Cl type of these waters indicates the possibility of seawater ingression/intrusion process during 2001 and comparatively mixed water type indicates the dilution activities of groundwater. Excessive withdrawal of groundwater has caused the increase of saline water intrusion. Improvement of groundwater quality in this Island due to artificial recharge structures made by NGRI under RGNDWM project and affects of the flood due to heavy rainfall of the months of September–October 2005 are discussed in this paper. [ABSTRACT FROM AUTHOR]

The present study investigated the chemical composition of rainwater at Kabir nagar, Nari, Nagpur, Maharashtra, India. The rainwater samples were collected on event basis during June–July–August-2006 and were analyzed for pH, major anions Cl, NO3, SO4) and cations (Ca, Mg, Na, K, NH4). The pH value varied from 6.0 to 7.3 (avg. 6.3 ± 0.3) indicating alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the monsoon season. The average and standard deviation of ionic composition was found to be 98.1 ± 10.6 μeql−1. The total anions contribute 45.1% and cations 54.9%, respectively to rainwater. Neutralization factors (NF) followed a sequence of NFCa > NFMg > $$ {\text{NF}}_{{\text{NH}}_{\text{4}} } $$ with factors of 1.1, 0.38 and 0.15 indicating the crustal components are responsible for neutralization of anions. The average ratio of (NO3 + Cl)/SO4 observed as 1.1 indicates that nitric and hydrochloric acid influences the acidity of rainwater. The ratio of NH4/NO3 and NH4/SO4 was observed as 0.68 and 0.34 indicate that the possible compounds which may predominate in the atmosphere are NH4NO3 and (NH4)2SO4. Ionic correlation was established to identify sources of origin. A good correlation was seen between Ca and Mg ( r = 0.95); suggesting the common occurrence of these ions from crustal origin. Similarly, the acidic ions SO4 and NO3 correlated well ( r = 0.60) indicating their origin from similar sources. Other relatively significant correlations were observed between Ca and SO4 ( r = 0.92), Mg and SO4 ( r = 0.83), Ca and NO3 ( r = 0.09), Ca and Cl ( r = 0.34) and Mg and Cl ( r = 0.31), and Mg and NO3 ( r = 0.71). The observed rainwater ratio of Cl/Na (1.1) is closer to that of seawater ratio (1.16) indicates fractionation of sea-salt and modifications by non-marine constituents as the site is 834 km away from the sea coast. The nss-Ca contribution was observed as 95.7% suggesting their crustal origin whereas nss-Mg and nss-K shows their contribution as 87.9% and 83.2% indicating influence of soil sources. The nss-SO4 contributed as 87.4% shows anthropogenic origin. [ABSTRACT FROM AUTHOR]

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected and analysed for pH, EC, TDS, F, Cl, HCO3, SO4, NO3, Ca, Mg, Na and K. In general, Ca, Na, Mg, HCO3 and Cl dominate, except in samples from mining areas which have higher concentration of SO4. Water chemistry of the area reflects continental weathering, aided by mining and other anthropogenic impacts. Limiting groundwater use for domestic purposes are contents of TDS, F, Cl, SO4, NO3 and TH that exceed the desirable limits in water collected from mining and urban areas. The calculated values of SAR, RSC and %Na indicate good to permissible use of water for irrigation. High salinity, %Na, Mg-hazard and RSC values at some sites limit use for agricultural purposes. [ABSTRACT FROM AUTHOR]

This article discusses the mobility of agricultural chemicals in the soil unsaturated zone during rice paddy cultivation in India. The authors studied the concentrations of nutrients and ions and used the nitrate and chloride data to model the movement of these chemicals. The model shows that the irrigation return flow and fertilizer application increases the nutrients and major ions concentration in the unsaturated zone. Also, soil mineralization and denitrification processes regulate the nitrogen concentration in the unsaturated zone.

Studies on monsoon precipitation chemistry were carried out to understand the nature of rainwater and sources of pollution at eight different locations in and around the National Capital Region (NCR) of Delhi during southwest monsoon in the years 2003–2005. These sites were Bulandshahr (BUL), Garhmuktesar (GAR), Muradnagar (MUR), Sardhana (SAR), Panipat (PAN), Charkhi Dadri (CHA), Hodal (HOD) and Bahror (BAH). The rainwater samples, collected at these locations, were analyzed for major anions, cations and pH. The data were assessed for its quality. In general, the order of concentrations of major ions was observed to be: Ca2+>SO4 2−>HCO3 −>NH4 +>Cl−>NO3 −>Na+>Mg2+>K+>F−. The average pH of rainwater at these stations was observed to be 6.39, ranging from 5.77 to 6.62, indicating alkaline nature. However, a few rain events, 31% at Panipat, 12% at Muradnagar and 29% at Sardhana, were observed to be acidic (pH<5.6). Acidity observed at Panipat and Muradnagar is attributed to industrial influence but at Sardhana to weak organic acids contributed by surrounding vegetation. No definite trends are found for most of the components at all the sites. However, concentrations of Cl− at Bulandshahr; NO3 − at Muradnagar and Hodal; F− at Panipat and Bahror; Na+ at Bulandshahr; K+ at Bahror and Bulandshahr; Ca2+ at Bulandshahr, Muradnagar, Charkhi Dadri and Sardhana; Mg2+ at Panipat, Bahror, Bulandshahr, Hodal and Sardhana have increased from 2003 to 2005. For source identification, principal component analysis (PCA) was made, which showed that in general, at all the sites; suspended soil–dust and sea salts which are natural sources, were identified as the most dominating. Sources like agriculture including cattle, brick kilns and industries were reflected in third or fourth PC indicating moderate influence of anthropogenic activities in this region. [Copyright &y& Elsevier]

Punjab is the most cultivated state in India with the highest consumption of fertilizers. Patiala and Muktsar districts are two agricultural dominated districts of Punjab located in extreme south-east and south-west of the state. This paper highlights temporal variations of the groundwater quality and compares its suitability for irrigation and drinking purpose in these two districts. Water samples were collected in March and September 2003, representing the pre-monsoon and post-monsoon seasons, respectively. Water samples were analysed for almost all major cations, anions, dissolved heavy metals and turbidity. Parameters like sodium adsorption ratio, % sodium, residual sodium carbonate, total hardness, potential salinity, Kelley’s ratio, magnesium ratio, index of base exchange and permeability index were calculated on the basis of chemical data. A questionnaire was also used to investigate perception of villagers on taste and odour. Comparison of the concentration of the chemical constituents with WHO (world health organization) drinking water standards of 2004 and various classifications show that present status of groundwater in Patiala is better for irrigation and drinking purposes except for a few locations with a caution that it may deteriorate in near future. In Muktsar, groundwater is not suitable for drinking. Higher total hardness (TH) and total dissolved solids at numerous places indicate the unsuitability of groundwater for drinking and irrigation. Results obtained in this forms baseline data for the utility of groundwater. In terms of monsoon impact, Patiala groundwater shows dilution and flushing but Muktsar samples show excessive leaching of different chemical components into the groundwater leading to the enrichment of different anions and cations indicating pollution from extraneous sources. No clear correlation between the quality parameters studied here and perceived quality in terms of satisfactory taste response were obtained at electrical conductivity values higher than the threshold minimum acceptable value. [ABSTRACT FROM AUTHOR]

Due to uneven spatial and temporal distribution of rainfall and lack of sufficient water management technologies, the development activities of the society are totally depending on groundwater resources. In addition to the prevailing drought-prone conditions, the improperly treated and unplanned release of effluents of industry, municipal and domestic into the nearby streams and ponds and the majority usage of groundwater for irrigation are increasing the ionic concentration of the groundwater and making it more saline. The analytical results of the collected groundwater samples show that the groundwater is alkaline, and sodium and bicarbonate are the dominant cation and anion, respectively. Gibbs variation diagram shows that the control of the chemistry of groundwater in the study area is the weathering of granitic gneisses and also the leaching of evaporated and crystallized ions from the topsoil of the irrigated areas and improperly treated industrial effluent ponds. GIS, a potential tool for facilitating the generation and use of thematic information, has been applied and analyzed for identification of groundwater quality suitable zones for domestic and irrigation purposes. 30.06% of the area is with suitable, 67.45% of the area is with moderately suitable and 2.45% of the area is with unsuitable quality of groundwater for domestic purpose. 46% of the area is with suitable, 53.36% of the area is with moderately suitable and 0.64% of the area is with unsuitable quality of groundwater for irrigation purpose. [ABSTRACT FROM AUTHOR]

The study area Chennai, the capital of Tamil Nadu is the fourth largest metropolis in India. Four areas were chosen in North Chennai, namely Manali, Ennore, Ambattur and Thiruvottriyur. Groundwater samples were collected from thirty-five stations covering the four areas during pre-monsoon and post-monsoon of the year 2000-01 and were analysed for physicochemical characters. The type of water that predominated in the study area was assessed based on hydrochemical facies. Besides, suitability of groundwater for irrigation was evaluated based on sodium adsorption ratio, per cent sodium, residual sodium carbonate and the US salinity diagrams. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

Abstract: Rainwater samples during the monsoon of 2001 and 2002 were collected from Roorkee urban area, a medium sized “town group” situated on the right bank of Solani River, a tributary of the Ganga River, near the Himalayan foothills and analyzed for EC, pH, TSS, TDS and major ions. The median value of pH was 7.05, well above 5.6, which is the reference pH. The ratios of SO4 2−+NO3 − and Ca2++Mg2+ (TA/TC) have been considered for acidity. In this study, ratio of TA/TC is quite below 1.0, indicating alkaline nature of rainwater. The concentration of ions in rain water have been observed to follow the pattern Ca2+>HCO3 −>Cl−>NO3 −>Na+>Mg2+>SO4 2−>K+. In order to estimate the marine and non-marine contribution, sea salt fraction has been calculated taking Na+ as reference. All ionic ratios have been found to be higher than the recommended sea water ratios in all three types of land use, viz. residential, commercial and industrial, suggesting a significant contribution of non-marine origin for these components. A comparison with the data of the other Indian sites validates the inverse relation of Cl− and Na+ with distance from the sea and highlights higher Ca2+ concentration and lower SO4 2− concentration. [Copyright &y& Elsevier]

An investigation was carried out to understand the role of water level fluctuation on major-ion chemistry of groundwater in the Palar and Cheyyar river basins, southern India. As groundwater is the only major source of water for agricultural and drinking purposes in this area, it is important to know the effect of geological formations and agricultural activities on groundwater chemistry. Groundwater samples were collected once a month from 43 wells (641 samples in total), from January 1998 to June 1999, and analysed for major ions. The results indicate that the major-ion chemistry of the groundwater varies with respect to space. Groundwater occurring near the River Palar has a high concentration of major ions except calcium, due to the absence of any recharge from the river, whereas lower concentrations of major ions were observed in the central part of the study area due to the recharge of fresh water from a number of surface reservoirs. The major-ion chemistry of the study region is controlled by both mineral dissolution and anthropogenic activities. The relative contributions of mineral dissolution and anthropogenic contamination are estimated by a stoichiometric approach, which suggests that mineral dissolution is the dominant process in both the formations. The relation between water level fluctuations and major-ion chemistry indicates that major-ion chemistry is also greatly influenced by the water level fluctuations in different geological formations. Thus, the major-ion chemistry of groundwater in this region is greatly influenced by mineral dissolution, anthropogenic activities and water level fluctuations in different geological formations. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents dry deposition of major ions on tropical foliage (leaves of Ashok (Polyalthia longifolia) and Cassia (Cassia siamea)) at St John's, Agra, an urban site of tropical India on nonrainy, nondewy, and nonfoggy days. The deposition flux was higher on Cassia leaf than Ashok leaf probably due to a rougher surface as shown by scanning electron microscopy. Dry deposition of cations varies from 0.46 to 12.16 mg m-2 day-1 while anions vary from 0.04 to 3.24 mg m-2 day-1. The percentage contribution of alkaline components is greater than that of acidic components, indicating the alkaline nature of dry deposition. Two-way analysis of variance results reveal significant seasonal variation only for K+ SO42-, and F-; however, values varied season to season for Na+, Ca2+, Mg2+, Cl-, NO3-, and NH4+ also. The large seasonal variation in deposition flux may be due to meteorological conditions, diameter of particles, and variation in atmospheric level. SO42- and NO3- show significant correlation, indicating their origin from similar sources while significant correlation between Ca2+ and Mg2+ implies their origin from soil. Poor correlation between Ca2+ and SO42-, Ca2+ and NO3-, and Mg2+ and SO42- indicates that in addition to soil other sources also contribute to dry deposition. Low dry deposition fluxes of SO42- and NO3- compared to Ca2+ and Mg2+ may be due to low mass medium diameters of SO42- and NO3- and may be due to uptake through the stomatal pores abundant on leaf surfaces. Factor analysis was employed to identify the sources. F-, Cl-, SO42-, NO3-, and K+ are grouped together in the first factor, indicating their probable contribution from combustion, Ca2+, Mg2+, and NH4+ are grouped in factor II, which may be attributed to road dust and soil, and factor Ill includes mainly Na+ and F-, probably contributed from brick-kiln industries. Atmospheric concentrations of F-, Cl-, NO3-, SO42-, Na+, K+, Ca2+, Mg2+, and NH4+ were found to be 0.38, 2.28, 1.31, 2.74, 0.44, 0.59, 1.21, 1.2, and 2.29 μg m-3, respectively. [ABSTRACT FROM AUTHOR]