SO4 Concentrations Research Articles

Comprehensive evaluation of hydro-chemical processes, suitability, health risks, and sources of groundwater contamination using compositional data analysis, Nizampur basin, Pakistan

This study aimed to evaluate the level of contamination, health risks, hydro-chemical processes, and sources of contaminants in the groundwater of the Nizampur basin, northwestern Pakistan. Forty-eight (n = 48) groundwater samples from predefined locations were collected and analyzed using the standard procedure for a total of 13 parameters. Statistical techniques in the compositional data analysis perspective were used for the identification of sources. The results showed that TDS, Turbidity, SO4, and NO3 concentrations surpassed the limits in 44, 29, 25, and 48% of samples, respectively. The nitrate pollution index indicated that 48% of the samples were contaminated with nitrates, while the composite index PIG showed that only 22% of the samples indicated low pollution. A close association between the land use/land cover of the study area and NO3 contamination was observed. In general, the groundwater of the region could be categorized as fresh-very hard water (87.5%), the major hydro-chemical facies were, Ca–Mg–HCO3, followed by mixed Ca–Mg–Cl and Ca–Cl facies. The Van Wirdum diagram showed that groundwater was mainly influenced by rock weathering and profound human impact. Similarly, it was assessed using chloro-alkaline indices that reverse ion exchange is a governing hydro-chemical process. NO3 concentrations in the area have the potential to cause non-cancer ailments in 75% and 47% of the samples in children and adults respectively. Based on the assessments made using the compositional data analysis it was inferred that NO3, SO4, Cl, and Turbidity originated from human sources, while the rest of the parameters have natural/geogenic sources.

Chemical and thermal changes in hot spring waters and fumarolic gases related to volcanic unrest at Meakandake volcano, Japan: Results of long-term geochemical monitoring from 1986 to 2022

Phreatic eruptions at Nakamachineshiri and Ponmachineshiri reflect the vigorous fumarolic and hydrothermal activities of Meakandake volcano. Thus, phreatic eruptions are likely to reoccur in the future, and hydrothermal systems should be understood to mitigate the risks of potential future hazards. Here, we reveal the results of long-term geochemical monitoring of hot spring waters and fumarolic gases since 1986 and discuss the chemical and temperature changes in hot spring waters, discharging at the foot, related to volcanic unrest. In Nakamachineshiri, related to the increase in seismic and fumarolic activity since 2019, the HCl concentration of the fumarolic gas has increased, and δD and δ18O values have also increased to approach those of the andesitic water. Simultaneously, with the increase in fumarolic and hydrothermal activity, the temperature and Cl concentration of the Meakan Onsen (MO) hot spring water discharged at the western foot of Nakamachineshiri have increased. The chemical characteristics of the fumarolic gas and MO water indicate that they were derived from a hydrothermal system in the shallow subsurface of Nakamachineshiri. Thus, we can consider that the temperature and chemical increases in the MO water represent activation of the system, and monitoring the MO water provides important information for understanding the present state of Nakamachineshiri. At Ponmachineshiri, phreatic eruptions occurred in 1988, 1996, 1998, 2006, and 2008, and seismic and fumarolic activity has sometimes increased since 1986 when we began our monitoring program. At the western foot of Ponmachineshiri, hot spring water is discharged at Yunotaki (YNT_U and YNT_L) and Lake Onneto (ONT). The results of our monitoring suggest that the YNT_U water is formed by mixing thermal water with a high HCO3 molar ratio (HCO3-type) and thermal water containing Cl and SO4 (Cl-SO4-type), which causes temperature and chemical changes related to the mixing ratio of these thermal waters related to volcanic unrest, especially increases in seismic activity. The Cl and SO4 concentrations in the ONT water began to increase approximately two years before the phreatic eruptions and increase in fumarolic activity. Such chemical increases can be explained by the increase in the supply of Cl-SO4-type thermal water and are likely to indicate precursor changes in volcanic unrest. Therefore, we expect to utilize these hot spring waters to understand the present state of Ponmachineshiri and detect precursor changes to future volcanic unrest.

Mechanisms on the inhibition of alkali-silica reaction in supersulfated cement

The supersulfated cementitious system gains increasing popularity for lowering carbon emissions of the construction industry. However, the alkali-silica reaction (ASR) behavior of this sulfate-rich cement is still unclear. This study first reports the characteristics and suppressing mechanisms of ASR in supersulfated cement (SSC). The results show that nearly no ASR-induced expansion is found in the SSC even if 100% glass aggregates are used, while the expansion ratio of the traditional OPC is twenty times higher than the SSC. In the SSC, the further hydration of unreacted slag during the ASR test refines the pore size and enhances the compressive strength of the matrix. Meanwhile, the consumption of the alkali ions in the pore solution during the formation of N-A-S-H gel reduces the concentration of the alkali ions and the contact possibility with the aggregates. The high bulk electrical resistance of the SSC can mitigate the diffusion of alkali ions from the external solution to the mortar. Moreover, the higher Al/Si ratio of C-A-S-H in the SSC than C–S–H in the OPC system results in a higher adsorption capacity of Na+ due to the more negatively charged surface, reducing the concentration of alkali ions in the pore solution. Furthermore, the high concentration of SO42− in the pore solution of SSC can inhibit the diffusion of OH−. As a result, the low-carbon SSC system would be a promising cementitious material to mitigate the ASR risk.

Hydrochemical Characteristics and Controlling Factors in Wudu River Basin of Guizhou Province

TheWudu River is a typical mining-type watershed in the karst mountainous area of western Guizhou Province. Based on the collection of the main stream, tributaries, spring water, and mine water samples in Wudu River Basin, the hydrochemical characteristics and control factors of Wudu River Basin were studied using Gibbs diagram, Piper diagram, and mathematical statistics analysis, and the solute contribution rate of different sources was calculated. The results revealed that the pH value of the water in the Wudu River Basin ranged from 7.87 to 8.52, with an average of 8.14. The TDS values ranged from 135 to 243 mg·L-1, with an average of 191.7 mg·L-1. The major cations in natural river and spring water were Ca2+ and Mg2+, the major anion was HCO3-, and the hydrochemical type was HCO3-Ca. However, owing to the influence of mining activities, the major cations in some tributaries were Ca2+ and Na+, and the hydrochemical types transitioned to HCO3·SO4-Ca and HCO3·SO4-Ca·Na. The ion components of river water in Wudu River Basin were affected by mine water discharge and cation exchange, carbonate rock weathering, silicate rock weathering, and agricultural fertilization. The high concentration of SO42- and Na+in mine water was the primary source of SO42- and Na+in the tributaries of the Wudu River. The method for calculating chemical material balance showed that the contribution rate of carbonate rock weathering ranged from 44.12% to 86.92%, with an average of 74.32%. The contribution rate of mining activities ranged from 3.28% to 37.07%, with an average of 11.61%. Carbonate rock weathering was the main controlling factor of hydrochemical components in the Wudu River Basin; meanwhile, mining activities also had a certain impact on river water chemistry but they showed spatial heterogeneity. The average contribution rates of atmospheric precipitation, silicate rock weathering, agricultural activities, and domestic sewage were 3.75%, 4.67%, 2.85%, and 2.81%, respectively, which had a limited impact on the hydrochemical components of the basin.

Systematic observations of enhanced oil recovery and associated changes at carbonate-brine and carbonate-petroleum interfaces

Enhanced oil recovery (EOR) from carbonates is obtained by injection of controlled ionic strength brines containing “active ions” (e.g., SO42−, Mg2+, Ca2+). It is generally believed that this occurs through the interaction of the active ions at the carbonate-brine interface (e.g., within a thin brine layer separating the petroleum and the carbonate phases). Here, in-situ observations show how one active ion, SO42−, alters behavior at the carbonate-petroleum interface. Displacement of petroleum from initially oil-wet carbonate rocks using brines with variable SO4 concentrations systematically changes oil recovery, in situ contact angles, and connectivity of the oil phase, confirming that the active ion alters interactions at the oil/brine/carbonate interface, as expected. Measurements of model calcite-fluid interfaces show that there is no measurable sorption of SO4 to carbonate-brine interfaces but reveals that the carbonate-petroleum interface is altered by previous exposure to SO4-containing brines. These results suggest that EOR in carbonates is controlled indirectly by active ions. We propose that this may be due to a reduced oleophilicity of the carbonate caused by chemical complexation between the active ion and petroleum’s acidic and basic functional groups. This mechanism explains how both anions and cations act as active ions for EOR in carbonates.

Investigating river water quality assessment through non‐parametric analysis: A case study of the Godavari River in India

AbstractThis study examines temporal variations in water quality parameters of Godavari River. The present study examines the concentrations of seven water quality parameters, namely total alkalinity (Alk), calcium (Ca), chlorine (Cl), total hardness (Hard), magnesium (Mg), sodium (Na), and sulfate (SO4), using data from 1981 to 2005 at seven gauging stations, that is, Mancherial, Pathagudem, Nowrangpur, Jagdalpur, Perur, Konta, and Polavaram. A seasonal analysis (pre‐monsoon, monsoon, and post‐monsoon) is conducted to detect trends in water quality parameters. The study also uses normality tests Kolmogorov–Smirnov (K–S) and Shapiro–Wilk (S–W) which reveals nonnormal distribution in the majority of datasets, necessitating non‐parametric analysis. The concentration of Alk, Ca, and Hard is found to be significantly increasing trend at some stations during all three seasons, along with significantly decreasing trend found in the concentrations of Cl, Na, and SO4 using non‐parametric Mann–Kendall's (M–K) and Sen's Slope test. The concentration of Mg depicts mixed trends at different stations which may be due the variation in agricultural practices or industrial activities surrounding the stations. It is evident that none of the parameter exhibits statistically significant trends across all seasons at any station. The results of Sen's Slope test are found to be in good agreement with Mann–Kendall's test statistics. A second order auto‐regressive model (AR (2)) is successfully employed to predict and forecast the water quality parameters in present and future time steps. The authenticity of AR (2) model is assessed using Nash‐Sutcliffe (NSE) efficiency and coefficient of determination (R2). The values of NSE and R2 are found to be more than 0.85 for all parameters during all the three seasons, along with, the values of mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE). The results of coefficient of variation (CV) and persistence‐criterion (PC) also depicts that AR (2) can successfully be utilized in forecasting the water quality parameters. The research contributes insights for effective water resource management in Godavari River basin.

Solubilities of individual light rare earth sulfates (lanthanum to europium) in water and H2SO4 solutions (neodymium sulfate)

Rare earth elements (REE) are critical commodities with high accessibility risk due to monopolistic practices of suppliers and increased demand. The REE ores generally require aggressive conditions to dissolve the mineral matrix, and sulfuric acid attack is the most economical preferred treatment route. The main challenge to processing REE resources efficiently is the lack of reliable and recent data regarding the solubility of individual REE sulphates in water as a function of temperature. Therefore, solubilities of light REE sulfates (LaEu) were measured for binary REE2(SO4)3–H2O systems from 25 to 95 °C following both heating and cooling approaches. Additionally, solubility isotherms were determined for the ternary system Nd2(SO4)3–H2SO4–H2O system at 25, 55 and 95 °C from 0.05 to 0.5 M H2SO4. It was found that the solubility of light rare earth sulfates decreases with increasing temperature. Within the light REE series, solubilities increase from La to a local maximum for Pr (by one order of magnitude), followed by a sharp decrease to Nd and Sm. The solubility of Nd2(SO4)3 was moderately improved by the presence of H2SO4, as the solubility values increase by up to 30% in 0.5 M H2SO4 compared to the no acid case. This was explained by the formation of soluble sulfate complexes due to increased concentration of SO42− ions in solution. The increase in solubility resulting from sulfuric acid addition was more significant at higher temperatures, although temperature continued to have a negative overall effect. The nature of the saturating solid phases was determined by XRD analysis on samples collected before and after phase change temperature for Ce, Nd, and Pr sulfates, while only solids collected at 25 and 95 °C were analyzed for the compounds known to form a single type of hydrate over the entire temperature range: usually REE2(SO4)3•8H2O except for La2(SO4)3•9H2O.

Groundwater recharge processes in the Lake Chad Basin based on isotopic and chemical data

The Lake Chad Basin is Africa’s largest endorheic basin. Because water supply for the rural population and most of the urban population depends on groundwater, assessment of groundwater recharge is crucial. Recharge sources for the upper Quaternary aquifer are precipitation, rivers, and swamps. Using water chemistry, and environmental (18O, 2H, 3H) and carbon (14C) isotopes, recharge processes can be assessed and groundwater ages roughly estimated. For this purpose, more than 1,000 samples from groundwater, surface water and precipitation were analysed for hydrochemistry and environmental stable isotopes. Furthermore, 3H measurements and 14C values of dissolved inorganic carbon for groundwater from the northeastern part of the Basin are included in the evaluation. The environmental isotope distribution shows recent recharge from precipitation north of Lake Chad (Kanem Region), where very low 3H values indicate occurrence before the 1960s bomb peak. Focused recharge from fresh river water is typical for Salamat Region in south Chad and the Komadugu Yobe wetlands between Nigeria and Niger. Slightly high δ-values in water occur in the Waza Logone area between Chad and Cameroon. Groundwater along the Lake Chad shore and the Bahr el Ghazal corridor show high δ-values (δ18O –0.78 to 7.45‰, δ2H –13.6 to 30.8‰). Recharge is caused by surface water that undergoes evaporative processes before percolation. Groundwater ages of 600–4,150 years, estimated from 14C analyses combined with high SO4 concentrations, along the Bahr el Ghazal indicate that recharge was caused by residuals of the Mega Lake before it dried out completely.

Sources of antimony contamination and its migration into water systems of Xikuangshan, China: Evidence from hydrogeochemical and stable isotope (H, O, S, and Sr) signatures

The Xikuangshan (XKS) mine was selected for a comprehensive Sb-related hydrogeochemical study because of its significant Sb contamination in water systems. Hydrochemical data, specifically multi-isotope (H, O, S, and Sr) data, were conducted to elucidate the primary sources and migration processes of Sb responsible for water system contamination. At the XKS Sb mine, water is near-neutral to alkaline and is characterized by high concentrations of SO42− and Sb. Sb occurs as Sb(OH)6− (the dominant species) in these oxidized waters. The hydrochemistry is mainly controlled by carbonate dissolution and silicate weathering. δ2HH2O and δ18OH2O values indicate that the infiltration recharge of mine water and mining activities regulate the migration of Sb in groundwater. δ34SSO4 and δ18OSO4 values indicate that dissolved SO42− and Sb primarily come from stibnite oxidation, bacterial SO42− reduction has either not occurred or is extremely weak, and the reductive dissolution of Fe (III) hydroxides does not significantly affect Sb migration in water. The 87Sr/86Sr ratios further indicate that the discharge of solid mine wastes leaching and smelting water is a crucial source of Sb contamination in groundwater. In addition, the relationship between δ34SSO4 and δ87Sr values suggests the complexity of the contamination source and migration of Sb in water. Finally, a robust conceptual hydrogeochemical model was developed using isotopic tools in combination with detailed hydrogeological and hydrochemistry characterization to describe the contamination source and migration of Sb in water systems at the XKS Sb mine.

Significant changes in size distribution of aerosols in Beijing after clean air actions

Over the past few years, the physicochemical characteristics and sources of aerosols have changed following the implementation of strict clean air policies in Beijing. In this study, size-segregated particulate matters (PM) were collected using a micro-orifice uniform deposit impactor (MOUDI) in Beijing from July 2021 to June 2022 to understand the responses of particle size distribution and chemical composition to the implemented emission reduction measures. The results showed that although particulate pollution greatly improved, it is still severe in Beijing, especially in autumn and winter, with the annual average PM1.8 (aerosol particle with aerodynamic diameter less than 1.8 μm) concentration reaching 46.7 ± 37.4 μg/m3. NO3− was the most abundant ion in the particles throughout all seasons, and its proportion to water-soluble inorganic ions increased significantly with the aggravation of pollution. This highlights the importance and urgency of controlling mobile sources in future control measures. The highest concentration of SO42− occurring during summer demonstrates the effectiveness of fossil fuel combustion control in winter. The measured size distributions of PM and secondary inorganic ions were trimodal, which significantly differed from the observations conducted in Beijing using MOUDI before 2017, in which the measured size distributions of PM and secondary inorganic ions were bimodal. The enhancement of atmospheric oxidation and reduction of gaseous precursors can affect the formation path of aerosols, and thus, their particle size distribution. Aerosol aqueous-phase reactions play a vital role in pollution development, with the droplet mode further growing hygroscopically into a coarse mode during pollution maintenance.

Responses of halophilic microbial communities to changes in salt composition: Comparison between autotrophic nitrification and heterotrophic ammonia assimilation biosystems

The concentration and proportion of chlorine (Cl−) and sulfate ions (SO42−) in actual high salinity wastewater exhibit significant fluctuations due to their diverse sources. This study compared the response of halophilic autotrophic nitrification (AN) and heterotrophic ammonia assimilation (HAA) sludges to changes in salt composition. The results demonstrated that both the AN and HAA systems maintained high ammonia removal efficiency even when exposed to mixed salt ions or pure sulfate conditions. Increasing the concentration of SO42− resulted in an increase in extracellular polymeric substances content, sludge settleability, sludge hydrophobicity, and the relative abundance of Nitrosomonas in the AN system (from 2.3% to 10.4%). The dominant heterotrophic bacteria in the HAA system underwent turnover in response to changes in salt composition conditions. The robustness and the cooperation between microorganisms of the HAA system surpassed those of the AN system. This study provides scientific foundation for treating multi-ion high salinity wastewater.

Seasonal variation and sources of PM2.5 bound water‐soluble ions at Jammu city in the foothills of the North‐western Himalayas, India

In this study, PM2.5 aerosols were collected from the campus of the University of Jammu situated along the Shivalik foothills of the North‐western Himalayas in the Jammu urban area to understand the seasonal variability of PM2.5 mass concentrations and associated water‐soluble inorganic ions (WSIIs). Results showed that the annual average PM2.5 mass concentrations were average 65.02 μg/m3 which significantly exceeded the annual National Ambient Air Quality Standards (40 μg/m3) by ~1.6 times. In addition, PM2.5 and WSIIs mass concentrations exhibited significant seasonal variability with the highest average concentrations observed during winter and the least during monsoon. Furthermore, WSIIs accounted for 24.56% of PM2.5 mass annually. Cl−, Na+, Ca2+ and Mg2+ depicted higher concentrations in summer whereas higher mass concentrations of SO42−, NO3− and NH4+ observed during winter pointed to their formation from gas to particulate conversion mechanisms. The variability of source strength during peak tourist seasons in holidays, festivities and new year appears to have significantly accounted for high PM2.5 in the study area. Additionally, meteorological conditions also appear to have played an important role in secondary aerosol formation which is noticeable from the high correlation observed among SO42−–NO3− (0.97), NH4+–SO42− (0.69), K+–Cl− (0.85), NH4+–NO3− (0.64), SO42−–K+ (0.63), NH4+–Cl− (0.65) at p < .05 during winter. On the other hand, significant correlations (p < .01) observed between Ca2+–Mg2+ (0.94), SO42−–Ca2+ (0.78) and SO42−–Mg2+ (0.89) during summer indicated their primary origin as crustal‐based sources.

Microbial distribution characteristics related to carbon cycle and their potential impact on methanogenesis of coal reservoirs in underground in situ environments

Microorganisms are one of the main driving forces of the cycle of carbon and other life elements in the underground environment. The natural environment is the comprehensive result of these microorganisms. In contrast, the study of coal reservoir microorganisms is mostly under laboratory conditions, which limits people's understanding of the symbiotic relationship between microorganisms, the interaction between microorganisms and the environment, and the distribution differences of microbial communities in the region. Similarly, the carbon cycle of the underground environment driven by essential microorganisms in coal reservoirs cannot be further studied. The geochemical process of underground methane generation and oxidation is critical in discussing the production and consumption of biomethane in the underground environment and the metabolic behavior of microorganisms. For this reason, we conducted biogeochemical tests and microbial sequencing on the water produced by coalbed methane wells in the south of the Qinshui Basin to analyze and improve the understanding of the distribution difference and metabolic behavior of microbial communities in coal reservoirs. The concentration of Cl− and HCO3− in the detention environment in the study area increases, while the concentration of SO42−, NO3−, NO2−, and Fe3+ decreases with the increase of coal seam depth, reflecting the distribution difference of hydrochemical environment and redox conditions of the underground reservoir in the study area. The results of microbial sequencing showed microbial methanogenesis in the study area, but it could also be consumed by microbial oxidation simultaneously. The microbial communities related to methane production and consumption had diversity distributions similar to geochemical parameters and geographical patterns. Methanogens and dissolved inorganic carbon isotopes confirmed the potential of in situ methane generation. Still, biomethane's enrichment and accumulation conditions and the impact of aerobic/anaerobic oxidation of methane need further study.

Experimental investigation of wettability alteration, IFT reduction, and injection schemes during surfactant/smart water flooding for EOR application

In recent years, the application of smart water and surfactant in order to improve oil recovery has attracted special attention in carbonate reservoirs. In this research, the effects of various salts in smart water and two surfactants of Cetyl Trimethyl Ammonium Bromide (CTAB) and Sodium Dodecyl Sulfate (SDS) on the wettability alteration of carbonate rock and IFT were studied. Besides, along with micromodel flooding, core flooding tests were conducted to assess the amount of oil recovery at reservoir conditions as an injection scheme was used. In this regard, the results illustrated that the presence of CTAB or SDS in seawater (SW) can act better in contact angle reduction compared to smart water. Also, a four times increase in the concentration of SO42− and removing Na+ from SW reduced the contact angle to 68° and 71°, respectively, being the best possible options to alter the carbonate surface wettability to more water-wet states. Moreover, in the second-order process in which the rock section was first placed in SW, and then was put in the smart solution (with or without surfactant), CTAB had a great effect on the wettability alteration. In the case of IFT reduction, although SW4Mg2+, compared to other ions, better decreased the IFT to 17.83 mN/m, SW + SDS and SW + CTAB further declined the IFT to 0.67 and 0.33 mN/m, respectively. Concerning different ions, divalent cations (Mg2+ and Ca2+) show better results in improving oil recovery factor. However, the combination of SW and surfactants has a more positive effect on boosting oil recovery, as compared to smart water flooding. It should be mentioned that the first-order injection is better than the second-order one since SW is flooded at first, and then, after the breakthrough, smart water is injected into the micromodel. In addition, the core flooding tests showed that SW + CTAB and SW + SDS in tertiary injection increased the oil recovery to about 59 and 57%, respectively, indicating that the presence of CTAB could be more effective than that of SDS.

Large-Scale Hydraulic Performance Testing of a Geotextile Mechanically Stabilized Earth (MSE) Wall Constructed with Recycled Concrete Aggregate Backfill

Abstract Constructing geosynthetic mechanically stabilized earth walls with recycled backfill materials reduces environmental impacts and financial cost compared with their gravity wall counterparts. While a large database of column-scale tests to evaluate the hydraulic performance of recycled backfill materials exists in the literature, clogging potential under multidimensional flow conditions has not been examined. A large-scale reinforced soil wall and a complementary column test constructed with recycled concrete aggregate (RCA) and closely-spaced woven geotextile reinforcement were tested to examine chemical and physical clogging under wetting-drying cycles. Internal moisture migration and the evolving chemical signature of leachate were measured. Geotextile samples were exhumed after the tests and analyzed to evaluate chemical (tufa formation) and physical (fines migration) clogging. The complementary multidimensional and column experiments afford direct comparison of outflow chemistry and effects on geotextile permittivity. Geotextiles in the large-scale wall and column tests did not show any evidence of chemical or physical clogging and no evidence of positive pore pressures was detected. Outflow leachate from the wall test had higher total dissolved solids values and higher concentrations of Ca and SO4 in comparison to the column test. The pH of leachate from the column test is initially lower than from the wall, but results become similar (pH ∼12) at test completion. Leachate from both tests is supersaturated with tufa minerals. Differences in leachate characteristics of the two tests can be attributed to the initial moisture content of the backfill, larger quantity of RCA material in the large-scale wall, and the multidimensional flow characteristics of the large-scale wall. Results validate previous observations from column tests in terms of moisture retention and chemical response when flow conditions are multidimensional. Maintaining a free-draining backfill under conditions that could promote clogging (closely-spaced woven geotextile reinforcement layers) gives further confidence in using RCA as backfill under these conditions.

Impact of nitrogen and sulfur fertilizers on leaching behavior of heavy metals from aquifer sediments to groundwater

BackgroundThe groundwater of the Bathinda district of Punjab is contaminated with heavy metals, nitrate (NO3), and sulfate (SO4) exceeding the BIS limits for drinking water in many areas. The article attempts to understand the role of fertilizers, nitrate and sulfate, in the mobilization of heavy metals from the aquifer minerals. MethodHeavy metal mobilization from aquifer sediments was studied through batch experiments using artificial groundwater (AGW) with varying concentrations of NO3 and SO4. For actual field conditions, column experiments were conducted with artificial groundwater containing 50 ppm NO3 as mobile phase and 1 ml/minute flow rate. The leached metal ions from the sediments were analyzed with ICP-MS. Significant findingsIt was found that compared to the AGW without NO3 and SO4, the heavy metal mobilization potential of AGW with NO3 and SO4 was significantly enhanced. The presence of nitrate significantly influenced the leaching of Cr, Co, Ni, Zn, and Hg, moderately affected the mobilization of As, and least impacted the mobilization of Fe, Mn, Cu, Cd, Pb, and U. An increase in leaching of Cr, Mn, Ni, Zn, As, and U was observed with the increase in SO4 concentration from 0 to 400 ppm, however, drastic reduction was observed with SO4 concentration of 500 ppm indicating high concentration of SO4 is posing an inhibitory action. The concentration of Cr, Fe, Co, Ni, Cu, Zn, Se, and Pb were significantly positively correlated indicating similar processes driving the mobilization of these metals. To reduce the mobilization of toxic heavy metals from the aquifer sediments, the NO3 and SO4 from the wastewater and agricultural run-off should be removed/reduced to the extent possible through optimized fertilizer usage, use of organic fertilizers, and treating the wastewater before discharging in the environment.

Analysis of Drinking Water Quality in Honakere Hobli

Abstract: Water is the most essential and valuable natural gift to mankind as well as the producer and consumer of this planet. Without water there would have been no life, hence it is a matrix of life.It is vital for many aspects of economic and social development. To analyse water quality, different approaches like statistical analyses of individual parameters, multi-stressors water quality indices. Rivers are the lifeline of living beings and constitute an integral part of both rural and urban communities as a source of drinking and cooking purposes. Water used by the public must be free from disease-causing bacteria, toxic chemicals, and excessive amounts of minerals and organic matter. It is important to test the suitability of water quality for its intended purpose, whether it is livestock watering, irrigation, spraying, or drinking water. The purpose of this section is to provide water quality testing information for the village of Nagamangala Taluk that will assist residents using a water supply. It provides information on the importance of water quality monitoring. Out of 20 villages, 8 villages’ water samples are not ideal for drinking purposes because of the higher concentration of TDS, TH, Cl, Ca, SO4, Fe, alkalinity, Mg, and Cd is more in that water samples. And other village water samples are suitable for drinking purposes. Since most of the families from the economically weaker sections of the society directlyconsume the tap water supplied by the village water supply system without any treatment.However, it is important to monitor the quality of drinking water regularly in rural areas where there is more population growth.

Preparation and Properties of Low-Carbon Foamed Lightweight Soil with High Resistance to Sulphate Erosion Environments.

Foamed lightweight soil (FLS) is a lightweight cementitious material containing a large number of tiny closed pores and has been widely used as a filler in places such as railways, roads and airports. However, there has been little research into the resistance of FLS to sulphate attack in practical engineering applications. The performance of FLS against different sulphate erosion concentrations was studied to elucidate the engineering characteristics of using large volumes of FLS as fill material for the road base in the construction of intelligent networked vehicle test sites. The results showed that the compressive strength of FLS prepared using 30% Portland cement (C), 30% granulated blast furnace slag (GBFS), 40% fly ash (FA) and a small amount of a concrete antiseptic agent (CA) as cementitious materials reached 0.8 and 1.9 MPa at 7 and 28 d, respectively, when the wet density was about 600 kg/m3, which met the design requirements. The FLS prepared via the above-mentioned cementitious system had a low carbon emission, with a CO2 emission reduction rate of up to 70%. It also had excellent sulphate attack resistance: the corrosion resistance coefficient of the cementitious material system reached 0.97, which was considerably better than that of C (0.83). For an erosion medium environment with SO42- concentrations of less than 1000 mg/L (moderate), 40% GBFS or FA can be used to prepare FLS. When the concentration of SO42- is less than 4000 mg/L (severe), 30% C, 30% GBFS and 40% FA can be used as cementitious materials, preferably in combination with an appropriate amount of CA, to prepare FLS.

Human health risk assessment of trace elements in PM10 for industrial areas in Gujarat

Introduction: The present study examines human exposure to Particulate Matter (PM10) and analyses potential health concerns in the industrial zones of Ankleshwar and Vapi in Gujarat.
 Materials and methods: For Ankleshwar and Vapi, 120 samples were collected, and characterisation was carried out to determine the concentration of NO3, SO4, NH3, K-S, Na, EC, OC, Al, Si, Fe, K, Ti, Ni, Br, Ca, Cl, Mn, Pb, Cr, Zn, S, V, and Cu in PM10 mass. The health risk from exposure to different trace elements, including both carcinogenic and non-carcinogenic, is evaluated for three distinct paths of ingestion, inhalation, and skin contact.
 Results: The Excess Cancer Risk (ECR) values for Cr and Pb for the ingestion pathway and the carcinogenic risks for Cr, Ni, and Pb for the inhalation pathway are both found to be higher than the minimal permissible threshold (1×10−6) for both children and adults for Ankleshwar and Vapi. However, for Ankleshwar and Vapi, the carcinogenic risks from dermal exposure to Cr and Pb are found to be lower than the permissible limit for both adults and children. It is observed that non-carcinogenic Hazard Index (HI) values for the skin contact and ingestion routes are less than 1 for both children and adults for Ankleshwar and Vapi. While the HI value for the inhalation pathway is found to be larger than the tolerable limit of 1 for both adults and children.
 Conclusion: For the purpose of creating sustainable cities and improving the health of the urban population, this study will provide a fundamental basis and help the governing authorities design mandatory pollution prevention and control methods, restoration plans, and systematic monitoring programmes.

Integration of the sulfate reduction and anammox processes for enhancing sustainable nitrogen removal in granular sludge reactors

The Anammox and Sulfate Reduction Ammonium Oxidation processes were compared in two granular sequencing batch reactors operated for 160 days under anammox conditions. It was hypothesized that increasing the concentration of SO42− may positively influence the rate of N removal under anaerobic conditions and it was tested whether SO42− reduction and anammox occur independently or are related to each other. The cooperation of N-S cycles by increasing the concentration of influent SO42− to 952 mg S/L in the second reactor, a higher ammonium utilization rate and sulfate utilization rate was achieved compared to the first reactor, i.e., 2.1-fold and 15-fold, respectively. Nitrosomonas played the dominant role in the N metabolism, while Thauera – in the S metabolism. This study highlights the benefits of linking the N-S cycles as an effective approach for the treatment of NH4+ and SO42− – rich wastewater, including lower substrate removal cost and reduced energy consumption.