Water Sulfate Concentrations Research Articles

Gadolinium Concentration Measurement with an Atomic Absorption Spectrophotometer

Abstract Because gadolinium (Gd) has the highest thermal neutron capture cross section, resulting in an 8 MeV gamma cascade upon capture, it has been proposed for dissolution in water Cherenkov detectors to achieve efficient neutron tagging capabilities. Whereas metallic Gd is insoluble in water, several compounds are very easy to dissolve. Gadolinium sulfate, Gd2(SO4)3, has been thoroughly tested and proposed as the best candidate. Accurate measurement of its concentration, free of doubt from impurities in water, is crucial. An atomic absorption spectrophotometer (AAS) is a device that suits this purpose and is widely used to measure the concentration of many elements. In this study, we describe three different approaches to measure Gd sulfate concentrations in water using an AAS: doping samples with potassium and lanthanum, and employing tantalum and tungsten platforms.

Application of a multiscale approach for modeling the rheology of complex fluids in industrial mixing equipment

Many industrial sectors, like the personal care one, make wide use of mixing processes that involve complex fluids. However, modeling the rheology of these fluids is still challenging due to their non-Newtonian behavior, which depends also on the local composition. Computational tools such as dissipative particle dynamics (DPD) have been already used to calculate the equilibrium properties of these systems. Moreover, different works have been focused on the calculation of transport properties from these mesoscale DPD simulations. Multiscale approaches have been proposed to couple rheological information from DPD with computational fluid dynamics (CFD) simulations. The CFD technique reproduces the macroscale piece of equipment, implementing a rheology model built using the Gaussian process regression, a mathematical tool related to machine learning. In this work, such a framework is tested on an industrial process, to assess its performance on a realistic application. The investigated system is a solution at a high concentration of sodium lauryl ether sulfate in water under laminar fluid dynamics regime. The results show that the mixture correctly exhibits a shear-thinning behavior and presents viscosity values in good agreement with rheology experiments. While the feasibility of the coupling approach is shown, further studies on DPD are needed to improve the accuracy and the predictability of the methodology.

Effects of climate and acidic deposition on interannual variations of stream water chemistry in forested watersheds in the Shimanto River Basin, southern Japan

AbstractAlthough the amount of acidic deposition has recently decreased in Japan, it has still deteriorated some forest ecosystems during the past several decades. Moreover, recent climate changes can affect stream water chemistry. We investigated the temporal trend and effects of climate conditions on stream water chemistry for more than 20 years in two areas (Yusuhara and Taisho) in the Shmanto River Basin, southern Japan, where the effects of acidic deposition are considered to be modest. Stream water samples were collected monthly from three forest watersheds selected at each site. The annual means of the stream chemistry were predicted by multiple regression analysis. The ammonium, nitrate, and sulfate concentrations in the bulk precipitation have decreased at Yusuhara, and the sodium, magnesium, calcium, chloride, nitrate, and sulfate concentrations in the stream water have decreased in both areas. The nitrate and sulfate concentrations apparently responded to the decreasing input of acidic deposition. The sunlight hours were positively related with the potassium, magnesium, calcium, nitrate, sulfate, and bicarbonate concentrations in stream water. The results suggest that long sunlight hours boost the photosynthetic activities, thus promoting soil respiration and decomposition of soil organic matter. Moreover, a higher carbonic acid concentration in the soil solution promotes cation weathering and carbonic acid dissociation to bicarbonate. Given the decreasing trends in magnesium and calcium concentration with no change in bicarbonate concentration, we inferred that previousinputs of acidic deposition enhanced the rate of rock weathering.

Effect of water sulfate and dietary bismuth subsalicylate on feed and water intake, ruminal hydrogen sulfide concentration, and trace-mineral status of growing beef heifers.

In the Northern Great Plains, cattle may be exposed to water with an elevated sulfate concentration resulting in ruminal hydrogen sulfide (H2S) production and risk of copper deficiency. There are currently few strategies available to help mitigate effects arising from high-sulfate water (HS). The objective of this study was to evaluate the effects of feeding a moderate-forage diet with or without bismuth subsalicylate (BSS; 0.0% vs. 0.4% DM basis) when provided water with a low- (LS; 346 ± 13) or HS (4,778 ± 263mg/L) concentration on feed and water intake, ruminal H2S concentration, and liver and serum trace-mineral concentrations. Twenty-four Limousin × Simmental cross beef heifers (221 ± 41kg) were stratified based on initial liver Cu into a completely randomized block design with a 2 × 2 factorial treatment arrangement. Feed and water intake (measured weekly), ruminal H2S concentration (measured on days 42 and 91), liver (measured on days -13 and 91), and serum trace-mineral concentrations (measured on days 1, 28, 56, and 91) were evaluated. Initial liver trace-mineral concentrations were used as a covariate in the statistical model. Water intake tended to be reduced with the inclusion of BSS (P = 0.095) but was not affected by water sulfate (P = 0.40). Water sulfate and BSS did not affect dry matter intake (DMI; P ≥ 0.89). Heifers consuming HS had a ruminal H2S concentration that was 1.58mg/L more (P < 0.001) than LS. The inclusion of BSS reduced (P = 0.035) ruminal H2S concentration by more than 44% (1.35 vs. 0.75mg/L). Regardless of the water sulfate concentration, heifers fed BSS had lesser liver Cu concentration (average of 4.08mg/kg) than heifers not provided BSS, and when not provided BSS, HS had lesser Cu than LS (42.2 vs. 58.3; sulfate × BSS, P = 0.019). The serum concentration of Cu did not differ over time for heifers not provided BSS; whereas, heifers provided BSS had lesser serum Cu concentration on day 91 than on days 28 and 55 (BSS × time, P < 0.001). The liver concentration of selenium was reduced (P < 0.001) with BSS inclusion but the selenium concentration in serum was not affected by sulfate, BSS, or time (P ≥ 0.16). BSS reduced ruminal H2S concentration, but depleted liver Cu and Se. Moreover, sulfate concentration in water did not appear to affect DMI, water intake, or growth, but increased ruminal H2S and reduced liver Cu concentration.

Effect of sodium sulfate concentration in drinking water for beef heifers, and the in vitro effect of bismuth subsalicylate on H2S production and fiber disappearance

This study evaluated the effects of ( i) increasing the concentration of sulfate in drinking water on dry matter intake (DMI), water intake, ruminal fermentation, and apparent total-tract digestibility, and ( ii) water sulfate concentration and bismuth subsalicylate (BSS) dose on in vitro ruminal fermentation. Eight ruminally cannulated beef heifers (382 ± 45 kg) were used in a replicated incomplete 3 × 3 Latin square design. Water treatments contained low (342 ± 29 mg/L; LS), medium (2785 ± 72 mg/L; MS), or high (4948 ± 163 mg/L; HS) sulfate. Ruminal digesta was collected to evaluate water sulfate and BSS dose (0.0%, 0.2%, 0.4%, and 0.6% dry matter) on ruminal H2S production in vitro. Water intake increased linearly as water sulfate concentration increased ( p = 0.002), but DMI was not affected. Heifers drinking MS and HS had greater ruminal H2S at 10.5 h after water provision than LS (sulfate × time, p &lt; 0.001). In vitro H2S production (µg and µg/mL of rumen inoculum) increased and plateaued with increasing sulfate ( p &lt; 0.001) and was linearly reduced ( p &lt; 0.001) by increasing BSS dose. Increasing water sulfate concentrations did not negatively affect water or feed intake but increased ruminal H2S concentrations. Bismuth subsalicylate may reduce H2S production.

207 Effect of Sodium Sulfate in Water and Dietary Bismuth Subsalicylate on Feed and Water Intake, Ruminal Hydrogen Sulfide Concentration, and Trace Mineral Status of Growing Beef Heifers

Abstract Cattle consuming increased concentrations of sulfur (S) are at an increased risk for depletion of copper (Cu) and or S-induced polioencephalomalacia and there are limited mitigation strategies to alleviate risk for cattle consuming high sulfate water. This study evaluated the effects of feeding growing beef heifers bismuth subsalicylate (BSS; 0.0 vs. 0.4% DM basis) when provided water with a low (LS; 346 ± 13) or high (HS; 4,778 ± 263 mg/L) sulfate concentration on dry matter intake (DMI), water intake, ruminal hydrogen sulfide (H2S) concentration, and trace mineral status. Twenty-four beef heifers (221 ± 41 kg) were stratified based on initial liver copper concentrations collected 13 d before the start of the study, into a completely randomized block design using a high forage diet fed for 98 d. Feed and water intake (weekly), ruminal H2S concentration (d 42 and 91), and liver (pre-study and d 91) and serum trace mineral concentrations (d 1, 28, 56, and 91) were evaluated. Initial liver trace-mineral concentration was used as a covariate in the statistical model. Water intake tended to be reduced with the inclusion of BSS (P = 0.10) but was not affected by water sulfate (P = 0.40). Water sulfate and BSS did not affect DMI (P ≥ 0.89), but total S intake increased (P &amp;lt; 0.01) from LS to HS (17.6 to 51.0 g/d) resulting in diets that contained 0.28 and 0.78% S (DM basis). Heifers consuming HS had 1.58 µg/mL more (P &amp;lt; 0.01) ruminal H2S than LS. The inclusion of BSS reduced (P = 0.04) ruminal H2S concentration by 46%. Regardless of water sulfate concentration, heifers fed BSS had lesser liver Cu (average of 4.08 mg/kg) than heifers not provided BSS, and when not provided BSS, HS had lesser Cu than LS (42.2 vs. 58.3; sulfate × BSS, P = 0.02). Serum concentration of Cu did not differ over time for heifers not provided BSS; whereas heifers provided BSS had less serum Cu on d 91 than d 28 and 55 (BSS × time, P &amp;lt; 0.01). The liver concentration of selenium (Se) was reduced (P &amp;lt; 0.01) with BSS inclusion. The Se concentration in serum was not affected by sulfate, BSS, or time (P ≥ 0.16). Bismuth subsalicylate reduces ruminal H2S concentration, but depletes liver Cu and Se. Moreover, sulfate concentration in water does not appear to affect DMI or water intake but reduces liver Cu concentration.

Differences in and factors controlling organic matter enrichment in the Ziliujing Formation shale in the Sichuan Basin

Lacustrine shale oil and gas are important fields for unconventional exploration and development in China, and organic-rich shale deposition lays down the critical foundation for hydrocarbon generation. There are two sets of shale, the Dongyuemiao and Da’anzhai Members, in the Ziliujing Formation in the Sichuan Basin. To identify the differential enrichment characteristics of organic matter and clarify its controlling factors, geochemical analyses of organic and inorganic geochemical analyses were performed. The results showed that the total organic carbon content of the Dongyuemiao shale (1.36%) is slightly higher than that of the Da’anzhai shale (0.95%). The enrichment of organic matter in the two shales resulted from the comprehensive controls of paleoproductivity, paleoenvironment, and terrigenous input, but different factors have different effects. In addition, driven by climate, the change in the sulfate concentration in the bottom water further led to the different intensities of bacterial sulfate reduction in early diagenesis. This made a great difference regarding organic matter accumulation in the two members. In general, climate may have played a dominant role in organic matter enrichment in the two sets of shale.

The risk of pulmonary NTM infections and water-quality constituents among persons with cystic fibrosis in the United States, 2010-2019.

The prevalence of nontuberculous mycobacterial (NTM) pulmonary disease varies geographically in the United States. Previous studies indicate that the presence of certain water-quality constituents in source water increases NTM infection risk. To identify water-quality constituents that influence the risk of NTM pulmonary infection in persons with cystic fibrosis in the United States. We conducted a population-based case-control study using NTM incidence data collected from the Cystic Fibrosis Foundation Patient Registry during 2010-2019. We linked patient zip code to the county and associated patient county of residence with surface water data extracted from the Water Quality Portal. We used logistic regression models to estimate the odds of NTM infection as a function of water-quality constituents. We modeled two outcomes: pulmonary infection due to Mycobacterium avium complex (MAC) and Mycobacterium abscessus species. We identified 484 MAC cases, 222 M. abscessus cases and 2816 NTM-negative cystic fibrosis controls resident in 11 states. In multivariable models, we found that for every 1-standardized unit increase in the log concentration of sulfate and vanadium in surface water at the county level, the odds of infection increased by 39% and 21%, respectively, among persons with cystic fibrosis with MAC compared with cystic fibrosis-NTM-negative controls. When modeling M. abscessus as the dependent variable, every 1-standardized unit increase in the log concentration of molybdenum increased the odds of infection by 36%. These findings suggest that naturally occurring and anthropogenic water-quality constituents may influence the NTM abundance in water sources that supply municipal water systems, thereby increasing MAC and M. abscessus infection risk.

Determination of Critical Micelle Concentration of Sodium Dodecyl Sulfate in Distilled Water at 298.15K by Surface Tension Measurements

Surfactants are chemicals that adsorb to the interface between a solution and another phase (gases or solids) and self-assemble molecular clusters known as micelles in a solution (water or oil phase). Measurements of the surface tension of sodium dodecyl sulfate (SDS) in distilled water at 298.15K are reported. The increase of concentration of sodium dodecyl sulfate (SDS) in distilled water then decreased in surface tension at 298.15K. Critical micelle concentration (CMC) decreased with a decrease in surface tension. The graphs of surface tension versus concentration were made to determine the CMC of the solution.

Characterisation of Methane Production Pathways in Sediment of Overwashed Mangrove Forests

Methane (CH4) emissions in mangrove ecosystems may complicate the ecosystem’s potential carbon offset for climate change mitigation. Microbial processes and the mass balance of CH4 in mangrove sediment are responsible for the emissions from the ecosystems. This is the follow up of our previous research which found the super saturation of CH4 in the pore water of mangrove sediment compared to atmospheric CH4 and the lack of a correlation between pore water sulphate and CH4 concentrations. This study is going to investigate methane production pathways in the sediment of overwashed mangrove forests. Two approaches were used to study methanogens here: (1) the spread plate count method and the quantitative polymerase chain reaction (qPCR) method, and (2) laboratory experiments with additional methanogenic substrates (methanol, acetate, and hydrogen) to determine which substrates are more conducive to methane production. According to the qPCR method, methanogen abundance ranged from 72 to 6 × 105 CFU g−1 sediment, while SRB abundance ranged from 2 × 102 to 2 × 105 CFU g−1 sediment. According to the plate count method, the abundance of methylotrophic methanogens (the only group of methanogens capable of competing with SRBs) ranged from 8.3 × 102 to 5.1 × 104 CFU g−1, which is higher than the abundance of the other group of methanogens (0 to 7.7 × 102 CFU g−1). The addition of methanol to the sediment slurry, a substrate for methylotropic methanogens, resulted in a massive production of CH4 (up to 9 × 104 ppm) and intriguingly the control treatments with autoclaving did not kill methanogens. These findings suggested that mangrove ecosystems in the marine environment provide favourable conditions for methanogens and further characterisation of the methanogen involved in the process is required. As a result, future research in this ecosystem should include methane production in carbon offset calculations, particularly due to methylotropic methanogenesis.

The dependence of the efficiency of the ion exchange of manganese ions from water on the type and form of the ionite and its hardness

Drinking water must comply physical, chemical, bacteriological and radiochemical guidelines therefore its quality should be continuously monitored before being introduced into the distribution system. Water used for human consumption may come from various sources: groundwater, spring water; water from rivers, streams, lakes, among other. A large part of the population of Ukraine uses drinking water that does not meet hygienic requirements according to various indicators. Manganese compounds are quite often present in natural waters. Their quantitative content can vary in a wide range, depending on the region, it can be 0,5-10 mg/dm3. It is worth noting that with a high content of manganese compounds in water, their removal is a rather difficult task. Removal of manganese compounds from water can be implemented using the ion exchange method, which consists of filtering water through loading in salt or acidic form. At the same time, softening and desalination of water can occur simultaneously. Therefore, the ion exchange method should be used for comprehensive water purification, softening, and removal of manganese compounds.&#x0D; The article presents the results of obtained during the extraction of manganese ions from distilled and tap water using the strongly acidic cationite KU-2-8 and the weakly acidic cationite Dowex MAC-3. Cationites were used in Na+ and Ca2+ form. The concentration of manganese ions (Mn2+) was varied from 5 to 500 mg/dm3. It was shown that the sorption capacity of the cationite KU-2-8 depended on the concentration of manganese ions, the form of the ionite, the presence of hardness ions in water and was little dependent on the pH of the medium. The sorption capacity of the weakly acidic cationite increased with the increase in the concentration of manganese ions and with the increase in the pH of the medium, which changed with the change in the concentration of magnesium sulfate in distilled water. Sorption of manganese ions from tap water decreases for strongly acidic and weakly acidic cations, compared to solutions in distilled water, which is associated with competitive sorption of hardness ions. This is especially noticeable when using ionites in Ca2+ form in solutions in tap water. The use of ionites in Ca2+ form reduces their sorption capacity for Mn2+ and in distilled water to a certain extent. But this effect is smaller compared to tap water. The Thomas model was used in the work to estimate the full exchange capacity of weakly acidic cationite at low concentrations of MnSO4 solution in distilled water.

Biogeochemical shifts and zooplankton responses in post-CAAA northeastern lakes: The success of acid recovery, complexity of biological recovery, and value of long-term monitoring

Lakes in the northeastern U.S., as in other regions, experienced significant declines in water quality and ecosystem health in the mid to late 20th century as atmospheric deposition from industrial emissions caused surface waters to acidify. After the Clean Air Act Amendments of 1990 enhanced regulations to limit emissions of sulfur and nitrogen, many lakes in the Northeast recovered from acidification. The organisms that inhabit lakes are susceptible to these shifts, and zooplankton can serve as valuable indicators of lake ecosystem responses to shifts due to their position as primary consumers in the food web. We evaluated a large historical dataset from the U.S. Environmental Protection Agency (EPA) Eastern Lake Survey (ELS) of 143 lakes throughout the northeastern U.S. to understand how recovery from acidification and subsequent chemical changes influenced zooplankton body size and community composition. We observed significant changes in chemistry; surface water sulfate concentrations decreased by 22% in the ELS lakes between the two sample years of 1986 and 2004. Increasing concentrations of DOC are common from the combined influence of deacidification and climate change, and the ELS lakes experienced a 26% increase in DOC. Notably, in the more developed regions of our study area, chloride concentration in lakes tripled, likely due to increased use of road deicers, and this is related to a subsequent increase in calcium and magnesium base cations. Zooplankton body size increased significantly between 1986 and 2004 across all taxa, and body size of Daphnia species, which require higher amounts of calcium than other zooplankton taxa, was positively associated with high calcium lakes. Shifts in zooplankton community structure, however, were most strongly influenced by variation in ANC, sulfate, and DOC. Our findings indicate that, while surface water acidity has a strong influence on zooplankton community structure, zooplankton populations are likely on a different trajectory than a simple recovery due to multiple chemical changes, such as increased chloride, occurring in lakes undergoing acid recovery. These, along with changes in climate and land-use, elicit multiple simultaneous responses in zooplankton communities.

The Release of Pollutants through the Bleeding of Cemented Phosphogypsum Backfill: Link to Protocols for Slurry Preparation

The present study investigated the effects of protocols for slurry preparation on the release of pollutants into bleeding water from cemented phosphogypsum (PG) backfill. Backfill slurry was prepared using four different protocols in which different parameters varied, including binder/PG ratio, solid concentration, binder type and mixing procedure. The concentrations of phosphate, fluoride and sulfate and the pH values of the obtained bleeding water were measured. The results demonstrated that the slurry preparation protocols affected the quantities of pollutants through the concentrations of pollutants in bleeding water and the bleeding rate. On the one hand, the binder/PG ratio was the key factor influencing the concentrations of all pollutants in bleeding water. Comparatively speaking, the binder type and mixing procedure had an obvious influence on the fluoride concentration but had little influence on the phosphate and sulfate concentrations in the bleeding water. On the other hand, the protocols for slurry preparation affected the bleeding rate by determining the water retention and water content of the backfill slurry. The most effective protocol for slurry preparation for cemented PG backfill could reduce the bleeding rate and enhance the immobilization of pollutants, minimizing the phosphate concentration in bleeding water to below 0.2 mg/L. However, it appeared that the fluoride concentration was still tens of milligrams per liter (over the limit of 10 ten milligrams per liter), to which attention should be paid.

148 Effect of Increasing Sodium Sulfate in Water on Intake on Ruminal Fermentation and the in Vitro Effect of Bismuth Subsalicylate on gas Production and NDF Digestibility

Abstract This study evaluated in vivo effects of increasing sulfate concentrations of drinking water on dry matter intake (DMI), water intake, ruminal fermentation, and apparent total-tract digestibility, and in vitro effects of water sulfate and bismuth subsalicylate (BSS) dose. Eight ruminal-cannulated beef heifers (382 ± 45 kg) were stratified into two complete and one incomplete 3×3 Latin squares with 28 d periods. Water contained 341 ± 29 (LS), 2,785 ± 71 (MS), or 4,948 ± 163 mg/L (HS) sulfate. Feed and water intake, ruminal fermentation, and nutrient digestibility were evaluated. Ruminal gas samples were collected every 4 h on d 27 to analyze hydrogen sulfide (H2S) concentration. At the end of each period, digesta collected from heifers in the complete Latin squares were used for in vitro incubation to evaluate water sulfate and BSS dose (0.0, 0.2, 0.4, and 0.6% dry matter). Water intake was 7 L/d greater (P &amp;lt; 0.01) for HS than LS, while MS did not differ. Water sulfate did not affect DMI, but total sulfur intake increased with increasing water sulfate concentration (P &amp;lt; 0.01). Heifers drinking MS and HS had greater ruminal H2S for 10.5 h after water provision and HS continued to be greater for another 4 h relative to LS (sulfate hour, P &amp;lt; 0.01). Ruminal SCFA concentration, molar proportions of major acids, and nutrient digestibility were not affected (P≥0.19). There were no interactions between water sulfate and BSS in vitro. In vitro H2S production (µg/48 h) increased with increasing sulfate concentration (P &amp;lt; 0.01) and was reduced (P=0.05) by BSS inclusion. Neutral detergent fiber digestibility was not affected by sulfate or BSS. Increasing water sulfate concentrations did not negatively affect water or feed intake but did increase H2S concentration and production in vivo and in vitro, respectively. Bismuth subsalicylate may be a potential strategy to reduce H2S production.

Effects of seawater sulfur starvation and enrichment on Gracilaria gracilis growth and biochemical composition

The genus Gracilaria, largest biomass producer in coastal regions, encompasses a wide range of species including Gracilaria gracilis. Nowadays, there is a spate of interest in its culture in lagoon where the water sulfate concentration is variable. A laboratory culture was carried out to determine the sulfate concentration effect on their growth as well as their biochemical composition, which were 2.5, 27 or 50 mM, referred to as SSS (sulfur starved seawater), SW (seawater) and SES (sulfur enriched seawater).We found that the sulfate content of the surrounding medium is a key parameter influencing both the alga growth and its composition. However, seawater proved to be the most suitable environment to sustain alga growth, proteins, R-phycoerythrin and agar yields, but sulfur enrichment and starvation affects them. The sulfate degree of agar and therefore its quality is related to the medium sulfate concentration. We conclude that sulfur starvation (2.5 mM) for three weeks, led to severe growth retardation, lower agar yield and quality and indicated the limit potential of G. gracilis for mariculture under these conditions. These results demonstrated that the success of G. gracilis culture in the lagoon is feasible if sulfate concentration is closer to that of seawater.

Sulfur Biogeochemical Cycling and Redox Dynamics in a Shale‐Dominated Mountainous Watershed

AbstractSulfur (S) is an essential macronutrient and important component of the earth’s crust, and its cycling has critical impacts on trace metal mobility, water quality, and human health. Pyrite weathering is the primary pathway by which sulfur enters surface waters. However, biogeochemical cycling of sulfur in soils and the river corridor mediates sulfate exports. In this study, we identified the major forms of sulfur across multiple compartments and scales in a pristine mountainous watershed, including shale bedrock weathering profiles, hillslope soils, and alluvial floodplain sediments, in order to provide insight into biogeochemical sulfur cycling in a hydrologically variable alpine system. X‐ray absorption near‐edge spectroscopy (XANES) analysis of shale weathering profiles showed clear evidence of pyrite oxidation to sulfate, with large accumulations of intermediate S(0) (20%–53%). Micro‐scale XANES showed evidence of reprecipitation of pyrite at fracture surfaces within the permanently saturated zone. Organic sulfur dominated S speciation in shallow hillslope soil and floodplain sediment, with little evidence of reduced inorganic S. However, mackinawite formation, representing active sulfate reduction, was observed in saturated oxbow sediments and saturated weathered shale underlying floodplain sediments. Further evidence of sulfate reduction from aqueous sulfur isotopic analysis was observed in shallow groundwater transects across an Fe‐reducing meander, whereas increases in pore water sulfate concentrations implied sulfur oxidation at other locations. The data present an integrated picture of sulfur cycling in a shale‐dominated watershed, where riverine sulfate exports are mediated by biological cycling, particularly in redox‐stratified and temporally dynamic hyporheic zone sediments.

Analytical Study of TDS and Sulphate Concentration in Ground Water: A Case Study of Vatva Region of Ahmedabad District, Gujarat

Abstract: The most valuable natural resource for human life is groundwater. It is certainly required in all parts of life and wellbeing for energy generation, food production, industrial activities, maintenance of the environment and enhances sustainable development for future generations. Fresh groundwater has become a popular subject in recent years. Water is continuously contaminated in all nations. India is no special case to this marvel. In India, over 80% of the rural population depend on groundwater. People face a barrier in getting safe, portable drinking water since groundwater quality is impacted by public activity and utilities. The frequent monitoring of sources of groundwater and its quality helps to create and develop public awareness of groundwater resources. The area having high contamination of ground water is selected named as Vatva located in Ahmedabad district of Gujarat, due to urbanization and the presence of many chemical refineries and pharmaceutical firms in the vicinity. During the investigation, the most impacted pollutants, such as TDS, Nitrate, Chloride and Sulphate were valuated. QGIS is used to do a spatial distribution study of all of these parameters. Ground water quality index graphs are also generated using the IS 10500: 2012 drinking water quality standard as a reference. Keywords: Ground Water Contamination, Spatial Distribution, QGIS, TDS, Nitrate, Chloride, Sulphate

Sulfur isotopes reveal agricultural changes to the modern sulfur cycle

The environmental fates and consequences of intensive sulfur (S) applications to croplands are largely unknown. In this study, we used S stable isotopes to identify and trace agricultural S from field-to-watershed scales, an initial and timely step toward constraining the modern S cycle. We conducted our research within the Napa River Watershed, California, US, where vineyards receive frequent fungicidal S sprays. We measured soil and surface water sulfate concentrations ([SO4 2−]) and stable isotopes (δ 34S–SO4 2−), which we refer to in combination as the ‘S fingerprint’. We compared samples collected from vineyards and surrounding forests/grasslands, which receive background atmospheric and geologic S sources. Vineyard δ 34S–SO4 2− values were 9.9 ± 5.9‰ (median ± interquartile range), enriched by ∼10‰ relative to forests/grasslands (−0.28 ± 5.7‰). Vineyards also had roughly three-fold higher [SO4 2−] than forests/grasslands (13.6 and 5.0 mg SO4 2−–S l−1, respectively). Napa River δ 34S–SO4 2− values, reflecting the watershed scale, were similar to those from vineyards (10.5 ± 7.0‰), despite vineyard agriculture constituting only ∼11% of the watershed area. Combined, our results provide important evidence that agricultural S is traceable at field-to-watershed scales, a critical step toward determining the consequences of agricultural alterations to the modern S cycle.

Sulfur and Oxygen Isotope Records of Sulfate-Driven Anaerobic Oxidation of Methane in Diffusion-Dominated Marine Sediments

Organoclastic sulfate reduction (OSR) and sulfate-driven anaerobic oxidation of methane (SD-AOM) are the two major microbial pathways for sulfate consumption in marine sulfur cycle. The relative changes of sulfur and oxygen isotope ratios in pore water sulfate are affected by the mode of microbial sulfate reduction and have been applied as an indicator for assessing methane excess environments. However, so far, this isotope proxy fails to distinguish sulfate reduction processes fueled by the oxidation of organic matter or by diffusing methane. To better understand the mechanism of sulfur and oxygen isotope partitioning during OSR and SD-AOM, coupled sulfur and oxygen isotopic compositions of pore water sulfate (δ34SSO4 and δ18OSO4) were investigated from four methane diffusing sites (CL56, CL57, CL59, and CL60) of the South China Sea, supplemented by carbon isotopic composition of dissolved inorganic carbon (DIC) and sulfur isotopic composition of pyrite in bulk sediments. Pore water sulfate and DIC concentrations, as well as calculated net sulfate reduction rates suggest that the sulfate reduction at site CL57 was mainly dominated by OSR, whereas sites CL56, CL59, and CL60 were likely impacted by both OSR and SD-AOM. Furthermore, the trend of cross-plotting δ18OSO4 versus δ34SSO4 values from site CL57 was distinguishable from sites CL56, CL59, and CL60, although all study sites show similar patterns to those derived from methane limited environments. This further indicates the trajectory of sulfur and oxygen isotope partitioning was affected by the mode of sulfate reduction (i.e., OSR vs. SD-AOM). At site CL57, the low net sulfate reduction rate would lead to enhanced oxidation of intermediate sulfur species during OSR, thus leading to a higher slope in the δ18OSO4 vs. δ34SSO4 cross-plot (1.26). In contrast, the higher net sulfate reduction rates at sites CL56, CL59, and CL60 due to the impact from SD-AOM would lead to lower slopes in the δ18OSO4 vs. δ34SSO4 cross-plots (0.78 ± 0.11). This study provides new insights into the sulfur and oxygen isotope systematics during microbial sulfate reduction processes in methane diffusing environments.

Mixed salt precipitation and water evaporation during smart water alternative CO2 injection in carbonate reservoirs

The main objective in this study is to experimentally elucidate the challenges associated with smart water alternating CO2 (smart WAG-CO2) with regard to permeability impairment that occurs due to interaction between injection water-formation water and injection gas-water. For this purpose, static tests including compatibility and zeta potential measurement, and dynamic tests including water, dry and wet CO2 coreflooding experiments are conducted. The findings illustrate that formation scales due to mixing formation water and injection water are mixed-salt with SrSO4 as the dominant scale type. Despite the fact that zeta potential outcomes point up that an increase in sulfate concentration in the injection water advantageously leads to proper potential oil recovery, the coreflooding tests reveal that sulfate ion concentration is the main factor in controlling k/ki ratio; the more the sulfate concentration, the more the level of permeability impairment. During gas injection, evaporation phenomenon was observed, with the evaporation rate being function of core water saturation. In addition, as salinity increases, while evaporation rate is reduced, more salt precipitation occurs in the sample with higher salinity. The results exhibited that initial permeability is more effective than water salinity in changing gas effective permeability. The results of this study can aid the engineers working in upstream sections of petroleum industry to reduce the scale removal expenditures and enhance the smart WAG-CO2 technique.