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A novel coupled mechanical and mass transport lattice discrete particle model is developed to quantitatively assess the impact of cracks on the mass transport properties in concrete members subjected to short‐ and long‐term loading conditions. In the developed approach, two sets of dual lattice networks are generated: one to resolve the mechanical response and another for mass transport analysis. The cracks simulated by the mechanical lattice are mapped onto the transport elements to investigate the effect of cracks on the global transport properties in concrete members. A new quantitative relationship is proposed for the estimation of the diffusion coefficient based on local crack information, and the developed model is capable of describing both convection and diffusion mechanisms. Moreover, creep behavior is incorporated to account for the influence of cracks induced by long‐term loading conditions. Numerical results, in the form of dynamic changes in cumulative water and chloride contents in concrete members under tension, compression, and bending with various stress levels show remarkable accuracy when compared to available experimental observations. The developed model provides an effective means for incorporating mesoscale information in simulations of water and chloride transport in concrete members under varying short‐ and long‐term loading conditions. [ABSTRACT FROM AUTHOR]

The effects of chlorides on the corrosion of steel bars within a matrix comprising modified magnesium oxysulfide (MMOS) cementitious materials was investigated. The phase composition, morphology and distribution of steel corrosion products (SCPs) were studied. There was basically no corrosion of the steel bars in the MMOS cement without chlorides. A high chloride content and a high water/cement (w/c) ratio in the MMOS matrix had adverse effects on the steel bar corrosion. The primary SCPs in the MMOS mixes were iron oxyhydroxides (FeOOH) and ferric oxide (Fe2O3), while ferrous oxide (FeO) was only observed at low w/c ratios, indicating a lower degree of oxidation. The presence of di-iron nonacarbonyl (Fe2(CO)9) at high w/c ratios suggested a higher degree of oxidation. At lower w/c ratios, rust products readily diffused. Conversely, at higher w/c ratios, these products accumulated close to the steel bars, resulting in a compact structure. [ABSTRACT FROM AUTHOR]

Woody plant encroachment is influenced by interactions between the physical environment and vegetation, which create heterogenous microenvironments some of which favor shrub recruitment through mitigation of the abiotic environment. Encroachment of native shrub, Morella cerifera into grasslands on Hog Island, Virginia has been attributed to warmer winter temperature; however, recruitment of seedlings in grasslands may be impacted by multiple factors at the level of the microhabitat. Our study focuses on a critical gap in understanding factors specifically influencing M. cerifera seedling recruitment and survival. By experimentally planting M. cerifera seedlings at varying dune elevations and grass densities, we tested hypotheses that dune elevation influences the microclimate, soil characteristics and vegetation cover and that grass cover/density is related to shrub establishment. We tested these hypotheses through gathering data from temperature data loggers, conducting soil water content and chloride analyses, and determining percent cover of grasses relative to dune elevation. Results indicate that dune elevation was positively related to moderated temperatures with reduced temperature extremes and vegetation cover/composition that led to favorable locations for M. cerifera establishment and growth. Where dune elevation is > 2 m, we document an upper limit of grass cover on natural seedling establishment, suggesting a switch from facilitative to competitive effects with grass density. Overall, our work demonstrates interactions between dune elevation and medium grass density has a facilitative influence on M. cerifera establishment and can be used for future predictions of shrub growth with rising sea-levels. [ABSTRACT FROM AUTHOR]

The research was aimed at studying pitting corrosion, which precedes the appearance of fistulas in steel and cast-iron pipelines in water supply systems and leads to significant expenditures. The process of fistula formation is accompanied by the formation of tubercles and craters on the surface of a corroding metal. The study focused on examining the qualitative and quantitative composition of the solution, which is generated inside the tubercles during their growth. It was found that, during the operation of water pipelines, the concentration of aggressive chloride ions inside the tubercles increases significantly compared to the chloride content of the source water. The increase in chloride concentration leads to an accelerated corrosion rate, potentially causing the formation of fistulas over time. As a result of the study, a mechanism for changing the mineral composition of the solution inside the tubercles has been proposed. This is due to the manifestation of selective properties by a dense layer of tubercles. The study also examined the appearance of crystalline forms of corrosion products that form after removing pipes from the water supply system. The study also reveals the conditions of corrosion products emerging. Further studies on the structure and properties of a dense layer of corrosive sediment could be used to evaluate the effectiveness of various corrosion inhibitors. [ABSTRACT FROM AUTHOR]

Objective: We investigated the horizontal migration and transformation of nitrogen in soil with oxalic acid and inhibitors (e.g., nitrification inhibitors, DMPP, urease inhibitors, and NBPT) under different soil water contents to provide a basis for the efficient utilization of nitrogen fertilizer in agricultural production in karst areas. Methods: Four nitrogen fertilizers (e.g., ammonium bicarbonate, ammonium sulfate, ammonium chloride, and urea) were applied separately and combined with oxalic acid, DMPP, and NBPT. The ammonium and nitrate nitrogen contents in the different soil layers were measured. The soil columns were cultured through an indoor soil column simulation at water content levels of 30%, 40%, and flooded (50%) for 30 days. Results: Ammonium bicarbonate with inhibitors increased soil NH4 +-N content by 15.42-21.12%. Ammonium sulfate with oxalic acid or NBPT increased soil NH4 +-N content by 27.56-52.25% at 30% and 40% moisture content treatments, compared to ammonium sulfate alone. Urea with DMPP application significantly increased soil NH4 +-N content by 11.93-14.87% at 40% water content and flooded conditions. In all treatments, the NH4 +-N content in the soil treated with 30% water content of ammonium chloride with oxalic acid was the highest. The NH4 +-N content showed a decreasing trend with an increase in the water content. The NO3 --N content in soil treated with ammonium bicarbonate and DMPP was higher than that treated with other nitrogen fertilizers at 30% moisture. The NO3 --N content decreased with increased water content. Under all treatments, ammonium chloride with oxalic acid had the highest percentage of soil NH4 +-N and soil soluble inorganic nitrogen at 30% water content, with 55.29% and 55.97%, respectively. Conclusion: Among the nitrogen fertilizer treatments, the soil NH4 +-N content increased in ammonium bicarbonate with DMPP or NBPT, ammonium sulfate with oxalic acid or NBPT, and urea with DMPP. The four nitrogen fertilizers with DMPP increased the soil NO3 --N content. Nitrogen fertilizer combined with oxalic acid and inhibitors could effectively improve the effective use of nitrogen fertilizer. [ABSTRACT FROM AUTHOR]

The Lake Chad basin, located in the centre of northern Africa, is characterized by strong climate seasonality with a pronounced short annual precipitation period and high potential evapotranspiration. Groundwater is an essential source for drinking-water supply, as well as for agriculture and groundwater-related ecosystems. Thus, assessment of groundwater recharge is very important although also difficult because of the strong effects of evaporation and transpiration, as well as the limited available data. A simple, generalized approach, which requires only limited field data, freely available remote sensing data, and well-established concepts and models, is tested for assessing groundwater recharge in the southern part of the basin. This work uses the FAO dual- Kc concept to estimate E and T coefficients at six locations that differ in soil texture, climate, and vegetation conditions. Measured values of soil water content and chloride concentrations along vertical soil profiles together with different scenarios for E and T partitioning and a Bayesian calibration approach are used to numerically simulate water flow and chloride transport using Hydrus-1D. Average groundwater recharge rates and the associated model uncertainty at the six locations are assessed for the 2003–2016 time period. Annual groundwater recharge varies between 6 and 93 mm and depends strongly on soil texture and related water retention and on vegetation. Interannual variability of groundwater recharge is generally greater than the uncertainty of the simulated groundwater recharge. [ABSTRACT FROM AUTHOR]

Concrete structure performance continuously deteriorates during operation, and the performance is simultaneously affected by chloride corrosion and repeated traffic loading. Repeated-loading-induced cracks have an impact on the rate of chloride corrosion. Chloride-induced concrete corrosion also affect the stress level of the structure under loading. Therefore, the coupled effect of repeated loading and chloride corrosion on the structural performance needs to be investigated. An upgraded test device was developed for chloride corrosion testing of unsaturated concrete structures under repeated loading. Based on the experimental results, considering the influence of repeated loading on the moisture diffusion coefficient and the chloride diffusion coefficient, a chloride transport model for unsaturated concrete under the coupled effect of repeated uniaxial compressive loading and corrosion was established. The chloride concentration under coupled loading was determined by the Crank–Nicolson finite difference method and the Thomas algorithm, and then chloride transport under the coupled effect of repeated loading and corrosion was analyzed. The results showed that the stress level and the repeated loading cycles directly affect the relative volumetric water content and chloride concentration in unsaturated concrete. The effect of chloride corrosion is more severe in unsaturated concrete compared to saturated concrete. [ABSTRACT FROM AUTHOR]

The search of new solvents is currently focused on deep eutectic solvents (DES). However, there are not many ecotoxicological studies in different biomodels of DES that allow knowing how these chemicals affect to the environment along the trophic chain. In this manuscript, two DES at different proportion of water have been prepared and characterized from the ecotoxicological point of view. These solvents are glucose:choline chloride (2:5) and sorbitol:choline chloride (3:2) at different contents of water. To carry out the ecotoxicological study, three biomodels have been used: bacteria Aliivibrio fisheri (A. fisheri), crustacean Daphnia magna (D. magna) and algae Raphidocelis subcapitata (R. subcapitata). The obtained results show that the ecotoxicity of these chemicals depends on the biomodel used and the amount of water, being toxicity values lower for chemicals with higher water content. However, it is important to highlight that the ecotoxicity for all chemicals is quite low with effective concentrations, EC50 values above 1000 mg/L in all the studied cases. [ABSTRACT FROM AUTHOR]

A highly contributing factor to impairment of water quality is stormwater that flows across the urban landscape, picking up pollutants along the way, which is directed by a system of stormwater infrastructure to be deposited in the nearest water body. Though state regulations to manage stormwater are in place, there is a need to strengthen and expand them to address chloride impairment. Chloride impairment stems from the use of road salt during the winter season, and is a serious concern for current and future urban streams. The only cost-effective method to address this impairment is by reducing the amount that is used. Such a reduction must come from public and private property owners alike. This can be achieved through permitting via the National Pollutant Discharge Elimination System, which Maine is authorized to implement, or through the state-wide stormwater regulations that apply when property is developed. Not doing so means the quality of Maine's water will continue to further degrade, an unacceptable option in the face of the Clean Water Act and the health of the public and our environment. [ABSTRACT FROM AUTHOR]

In this study, we simulated and predicted the accumulation of deicing agents in the soil and water system of the study area (a ski resort in Beijing, China) and discussed the environmental impact of deicing agents on the surrounding water system and soil under a standardized dosage. The widely used sodium chloride deicing agent was selected, and the standardized dosage of the deicing agent was estimated. Analysing the prediction results of the changes in chloride ion content in water systems and soils after the use of deicing agents from 2021 to 2029 leads to the conclusion that the use of deicing agents will increase the chloride ion content of the study area. It is predicted that chloride ion content in the water system and soil will increase year-by-year from 2021 to 2026, achieving a stable trend after 2027. It is concluded that the deicing agent has no obvious effect on the surrounding water body and soil under the standardized dosage. This research is intended to fill the gap in quantitative research on the environmental impact of deicing agents, to provide a reference and guidance for the engineering application of deicing agents, and to offer support for the improvement of deicing agent management measures. [ABSTRACT FROM AUTHOR]

The adsorption, protective, and passivating effects of sodium salts of malonic and ethylmalonic acids on the oxidized and reduced surface of copper and MNZh 5-1 copper alloy in a neutral chloride solution have been studied. It was shown that sodium ethyl malonate anions, which are less hydrophilic than sodium malonate, have higher adsorption free energies () on copper and MNZh 5-1 alloy at E = 0.0 V. On copper, they are 69.4 and 47.7 kJ/mol, respectively, and they are 78.7 and 74.1 kJ/mol on the MNZh 5-1 alloy. Such values () indicate the chemisorption of anions of both inhibitors on the surface, and their stronger adsorption on the alloy, apparently, is due to its increased adsorption activity of the heterogeneous surface as compared to copper. The thicknesses of conditional monolayers of inhibitors on metal and alloy surfaces have been calculated. At cathode potential E = –0.60 V on the reduced copper surface, the values () are significantly less (for malonate and ethyl malonate, respectively, they are 38.3 and 64.2 kJ/mol). Corrosion testing of copper in water with a chloride content of 10 mmol/L also showed the advantage of ethyl malonate over malonate. At the same time, for Cin = 1.5 mmol/L, the degree of protection is 71 and 65%, respectively. Practically complete suppression of copper corrosion (degree of protection 91%) with sodium ethylmalonate is achieved at Cin = 3 mmol/L. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combined with ultrasound-assisted extraction (UAE), 9 choline chloride deep eutectic solvents (NADES) were screened for the extraction of antioxidant polyphenolic compounds from Mentha pulegium (Lamiaceae). • The extraction conditions were statistically investigated using Response surface methodology conducted by Boc-Behnken design (BBD). • The selected NADES extracts recorded excellent antioxydant activity (93%) higher than conventional organic solvent. • HPLC–MS/MS analysis revealed over 30 secondary metabolites: hydroxycinnamic acids and flavonoids dominated the extracts tested. • The antifungal activity of the optimized extracts revealed inhibition of over than 88% against the postharvest citrus fungal: Phytophthora citrophthora. With the introduction of the concept of green chemistry, eco-friendly extraction processes are moving from an option to a must. Combined with ultrasound-assisted extraction (UAE), 9 choline chloride deep eutectic solvents were screened for the extraction of antioxidant polyphenolic compounds from Mentha pulegium (Lamiaceae). Data indicated that among the 9 types of choline chloride-based solvents tested, Choline Chloride: Lactic acid (1:2) and Choline Chloride: Glycerol (1:2) were selected as the most promising solvent compared to 80 % methanol. The extraction conditions were statistically investigated using Response surface methodology conducted by Boc-Behnken design (BBD). The optimal operational conditions were: temperature of extraction 80 °C, extraction time of 30 and 51 min with 44 and 20 % water content in Choline Chloride: Glycerol (1:2) and Choline Chloride: Lactic acid (1:2), respectively. The selected NADES extracts recorded excellent scavenging activity at a concentration of 1,9 mg/ml higher than 93 %. HPLC–MS/MS analysis revealed that Phenolic acids mainly hydroxycinnamic acids, such as rosmarinic acid, chlorogenic acid, salvianolic acid, caffeoyl glucose, lithospermic acid, and its derivatives, dominated the extracts tested. Otherwise, our results support that the proposed eutectic solvents are able to provide a higher selectivity toward flavonoids such as apigenin derivative, kaempferol coumaroyl hexoside, epi gallocatechin and quercetin o glucopyranoside gallate. The antifungal activity of the optimized extracts revealed inhibition of over than 88 % against the postharvest citrus fungal: Phytophthora citrophthora. In light of the presented results and considering the nature of components constituting Natural deep eutectic solvents (NADES), make these green, novel, sustainable, and low-cost extracts fresh samples for further investigation. [ABSTRACT FROM AUTHOR]

Waste liquid treatment is widely concerned with the deepening of people's awareness of environmental protection, especially for the waste liquid with a high chemical oxygen demand (COD), which also has a high calorific value and makes it possible for the incineration treatment. In this study, the pyrolysis and combustion characteristics of pesticide waste liquid (PWL) are investigated by using thermogravimetric experiment and kinetic analysis, and the effects of different water and salt contents on its pyrolysis and combustion are discussed. The results show that both pyrolysis and combustion processes of the simulated pesticide waste liquid (sPWL) could be divided into two stages. As the water content increases from 0% to 18.5%, the volatilization characteristic index of stage Ⅰ (low temperature) increases by 263.31%, while that of stage Ⅱ (high temperature) decreases by 28.32%, and the water content could promote the pyrolysis and comprehensive combustion performance of the sPWL. As the sodium chloride contents increase from 0% to 1.5%, both the pyrolysis and combustion process of the PWL are enhanced, and the volatile release characteristic index, the ignition temperature and burnout characteristic index increase by 60.77%, 18.74% and 47.95%, respectively. By the means of the Coats-Redfern integral method, the kinetics of the pyrolysis and combustion of the PWL are analyzed, with a linear correlation coefficient of more than 95%. In a whole, a suitable water and sodium chloride content in the pretreatment process is crucial for efficient and low-cost treatment of waste liquid, which can promote the pyrolysis and combustion processes. These results are expected to provide several insightful guidance for the efficient treatment of the waste liquid. • The pyrolysis and combustion characteristics of pesticide waste liquid are studied. • The effects of the water and salt contents in pesticide waste liquid are analyzed. • The pyrolysis and combustion process of waste liquid is divided into two stages. • Water can promote pyrolysis and improve the combustion of the waste liquid. • The sodium chloride in waste liquid should be controlled in the pretreatment stage. [ABSTRACT FROM AUTHOR]

Despite human activities have currently increased the global flux of fluoride into the atmosphere and in rivers by more than a factor of 2 (Schlesinger et al., 2020), national water quality criteria for fluoride to protect freshwater biota have been established in only a few countries. Lastly, because the mean level of fluoride in freshwater across Canada is 0.05 mg F SP - sp /L (Environment Canada, 2001), Parker et al.'s (2022) water quality benchmarks (3.4-10.4 mg F SP - sp /L) would allow fluoride pollution levels 70-200 times higher than natural fluoride levels. [Extracted from the article]

An ion chromatography (IC) system with switching recycling column was developed for the determination of bromate in drinking water with high chloride content. The system included a pump, two switching valves, guard column and analytical column, suppressor and a conductivity detector. In this method, the single eluent was used for both online collection and matrix elimination, and bromate was eluted from the concentrator column to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r  = 0.9995) in the range of 1–100 μg/L and repeatability (RSD ≤ 4.80%, n  = 6). The limit of detection was 0.2 μg/L (S/N = 3) with 1000 μL sample volume injections. The method was applied to analysis of drinking and tap waters, and satisfactory recoveries of spiked samples between 96.8% and 108.7% were obtained. The result showed that the recycling column-switching system can be useful for the determination of traces of bromate in high-chloride samples, which is required in production of the drinking water and quality control of the final product. [ABSTRACT FROM AUTHOR]

This paper examines the identification of key indicators that could be used to measure the success of reclamation plants in post-exploration oil and gas mining areas. The main objective of this research was to find key indicators or variables for evaluating the level success of reclamation results in the post-mining of oil and gas area. In this study, 44 environmental variables of the physical, biological, soil, water and air indicators were analyzed from 70 field plots of 6 reclamation and 2 natural forest sites. The analysis methods included (1) cluster analysis using the Agglomerative Hierarchical Clustering method with the Ward's method, and (2) quadratic discriminant analysis. The results of the clustering analysis showed that there were some clusters due to variation of biomass, water, soil and air conditions. The three clusters developed based on water and/or air variables provided high cophenetic correlation (0.80) with low within-cluster (14.5%) and high between-cluster variations (85.5%). Based on the multicollinearity analysis, average vector difference test, variance matrix variance test, unidimensional test of each variable and quadratic discriminant function, this study found that there were 3 key indicators determining variations of the quality of the reclamation plantations within the study sites, namely, biological indicator of biomass volume (Bio_B); soil indicator of P content in the soil (Tnh_P), saturation base of soil (Tnh_Kb), Manganese (Mn) content in the soil (Tnh_Mn), Sulfur content in the soil (Tnh_S), percentage of ash in the soil (Tnh_Ab), percentage of clay in the soil (Tnh_Li), and water indicator of chloride content in the surface water (Air_Cl). The examination on four classes of the reclamation quality showed that the classes were successfully classified having excellent crossvalidation error matrix with overall accuracy more than 90%. [ABSTRACT FROM AUTHOR]

Four stations at twelve sites were selected on Tigris river from Aziziah to the center of Kut city, for a distance more than 90 km. The sites were in a cross -section from both river sides and in the middle. The physical and chemical characterization were studied over the period from June 20l6 to May 2017. Air and water temperatures were varied (11-49) °C and (12-34) °C respectively. Salinity values were (0.410 -0.726) PPT. pH values, conductivity, total dissolved salts and Sulphate were (6.7-8.3), (670 - 1170), (330 -590) and (116.5-242) respectively. Water turbidity was (5.12) and (53) NTU at stations 2 and 1 respectively. Dissolved Oxygen values were low during Summer and high for the other months of the year. BOD values were high during summer. Total hardness was (650-1190) mg/L. Nutritive values of phosphate was low in March for all stations, while values of Nitrite and Silica were low in June compared with other months. Total alkalinity and chloride were (l14-162) and (74.5-144.9) mg/L respectively. Results discussion based on the changes of the four stations and the effect of the river sites on the river water. The stations represent the city centres were the river pass through, depending on the population nature and agricultural area and their effect on the water quality and usages. [ABSTRACT FROM AUTHOR]

Nitrate and Residual Chloride have a great effect on human health when taken with drinking water in high concentrations. Therefore, this study is an attempt to evaluate the concentration of Nitrate and Residual Chloride in drinking water. Water samples were collected from household tanks in Al-Diwaniyah city-Iraq for six months (from January to June 2019). The study included most of Al-Diwaniyah neighborhoods, they numbered 15, and they are Al-Orouba First, Al-Orouba Second, Al-Orouba Third, Al-Dhubat, Al-Askari (Al-Sadr Fourth), Al-Jazzier, Umm Al-Khail, Al-Furat, Al-Judida, Al-Jamaa, Al-Nahda, Al-Iskan, Al-Taqiya, Sob Al-Shamiya, and Al-Jumhouri. The results of this study confirmed the variation in nitrate and residual chloride concentrations with different study months and sample locations. The lowest nitrate concentration was 3.19 mg/l in February in the Al-Jamaa neighborhood. The highest concentration was 5.15 mg/l in January in the Al-Taqiya neighborhood. The residual chloride reached its highest concentration of 4 mg/l in January in the Al-Jazzier neighborhood and the lowest concentration was 0 mg/l in May and June in the Al-Taqiya neighborhood and June in the Umm Al-Khail neighborhood. The results also showed that the nitrates did not exceed the Iraqi standard specification and international standards. While chlorine exceeded the specifications as there was no residual chloride in some samples or it did not reach the minimum required concentration. [ABSTRACT FROM AUTHOR]

The electrical resistivity of concrete is an important property in the assessment of reinforcement corrosion in concrete and an essential parameter in the design and operation of cathodic protection for reinforced-concrete (RC) structures. Water and chloride contents in concrete are highly variable in RC structures in real-world hostile environments, meaning that characterisation of their coupled effects on concrete electrical resistivity is important. The currently available models are investigated in this paper. As all the current models are purely empirical, an improvement with a semi-empirical model is proposed. The improvement highlights the intrinsic linkage between concrete electrical resistivity and water content and the pore size distribution of concrete. The proposed model was tested using two sets of experimental data and was also compared with other two empirical models. [ABSTRACT FROM AUTHOR]

Zubair area is located at the extreme part of the south of Iraq and represents the southern part of the western desert, bounded by the north latitudes 30o05'-30o25' and east longitudes 47o30'- 47◦55'. Groundwater is a major natural resource in the study area because no perennial river exists. Groundwater from twenty wells in the study area were analyzed in order to determine some of chemical variables such as major cations (Ca+2, Mg+2 ,Na+ ,K+ ) and major anions (CL- ,SO4-2 ,HCO3- ,CO3-2 ,NO3-) along with several physical variables such as hydrogen ion concentration (pH) , total dissolved solids (TDS), and electrical conductivity (EC). Hydro-chemical analysis showed that the groundwater of the study area is excessively mineralized, depending on the relation between EC and mineralization. Depending on total hardness (TH), all samples were with very hard water. High chloride concentration in the groundwater of the study area may be an indicator of pollution by sewage and agriculture fertilizers. The increase in flow length of the groundwater in the study area would change the water quality from bicarbonate to sulfate and chloride. The predominant cations recorded are calcium and magnesium along with chloride from the anions, so that the water type is Ca-Mg-CL for most samples. The water wells studied are not suitable for drinking purposes of humans. Depending on TDS and EC values, the water samples are not suitable for irrigation according to FAO 1997 classification. However, the results also revealed an excellent water class depending on Na percentage (Na%) and EC according to Todd 1980 classification for irrigation water. Also, an excellent water class (S1) for agriculture was recorded depending on SAR classification of Subramain, 2005. [ABSTRACT FROM AUTHOR]

The following study is aimed to determine the effect of rainfall on the quality of the groundwater in the Delhi-NCR region. Samples of groundwater were collected from a total of 10 sampling stations during the prerainfall/(June-July 2019) and post-rainfall (November-December 2019) seasons for the analysis of water quality parameters suggested by the World Health Organization. Lab tests were conducted to determine various physiochemical parameters of the water sample namely pH, Chloride (Cl-), Calcium Hardness (CH), Total Hardness (TH), Sulphate (SO4--), Nitrate (NO3-), Fluoride (F-) and Total Dissolved Solids (TDS). The Water Quality Index was then calculated and a brief comparison with the permissible values was also performed. The results show that most of the studied water sample were of poor quality in the case of post-rainfall collected water samples. [ABSTRACT FROM AUTHOR]

In this work, novel calibration curves and calibration surfaces of Electromagnetic (EM) characteristics are modeled as a function of the water and chloride contents of concrete. An experimental campaign was carried out on cores extracted from two types of concretes: C1 (Ordinary Portland Concrete) and C3 (62% slag + 38% clinker). The cores were initially saturated at three sodium chloride (NaCl) concentrations and then oven-dried to attain different degrees of saturation. They were tested with the electromagnetic and electrical cell to determine the dielectric permittivity and electrical resistivity, respectively, at the targeted hydric and chloride ion contents. The calibration curves and calibration surfaces, which represent the resistivity and permittivity as a function of chloride content and/or degree of saturation, were adjusted and presented for both concretes. The calibration surfaces developed herein serve as an essential tool to study complex phenomena, such as the coupled water-chloride ingress. • Developing novel calibration curves and calibration surfaces that correlate the permittivity and resistivity of concrete to its chloride and water content. • Investigating the impact of slag on the permittivity and resistivity of concrete. • Proposing a non-destructive methodology to monitor chloride and water content for reinforced concrete structures exposed to a tidal zone. [ABSTRACT FROM AUTHOR]

• The influence of several factors on heparin anticoagulant activity was investigated based on NMR spectrometry. • A linear dependence was found between anticoagulant activity and PC3 scores based on the non-targeted analysis. • The correlation between molecular weight and anticoagulant activity was linear over typical values for porcine heparin preparations. • Chloride and moisture contents were negatively influencing factors for heparin activity. Heparin is a carbohydrate polymer, which is clinically used as an anticoagulant for the treatment of thrombotic disorders. The anticoagulant process is mainly mediated by the interaction of heparin with antithrombin followed by inhibition of clotting factors IIa (FIIa) and Xa (FXa). The influence of polymer disaccharide structure, average molecular weight and impurity profiling (e.g., chloride and water content) was investigated by NMR spectrometry and principal component analysis (PCA) for a representative dataset of porcine heparin samples (n = 509). A significant linear dependence was found between anticoagulant activity and scores on the third principal component (PC3) based on the non-targeted analysis of 1H NMR fingerprints. The correlation between average molecular values and anticoagulant activity for the 24 porcine heparin samples from two manufacturers was linear (R = 0.85) over typical values for porcine heparin preparations. Chloride and water contents were identified as negatively influencing factors for the actual activity values as their presence decrease the "pharmaceutically active" organic part of heparin preparations. Some suggestions regarding manufacturing process are made according to the results. [ABSTRACT FROM AUTHOR]

Fixed-bed reactor (FBR) is a promising technology for realising robust high-rate nitrification. Only a few studies have investigated the effect of salinity on these systems. In this research work, the effect of gradual stepwise increase in chloride concentration (NaCl content) on the performance of high-rate nitrifying FBRs was studied at loading rates of about 1 kg NH 4 +-N∙m-3∙d-1 at 25 °C. Two lab-scale FBRs having stable biofilms (adapted to 4 g Cl−/L) grown on commercial media – plastic carrier fed with nanofiltration (NF) permeate of a landfill leachate concentrate, and clay beads fed with synthetic saline wastewater, respectively – were operated using up-flow velocities (u) of about 12 and 8 m/h, respectively, for a period of about 100 days, wherein the chloride content of the feed water was increased from 4 to 16 g/L (electrical conductivity: 13–45 mS/cm). On an average, the FBR packed with plastic carriers (u ≈ 12 m/h) offered ammonia removal percentages greater than 97%, whereas the FBR filled with clay beads due to its low bed porosity (and therefore, u ≈ 8 m/h only) gave nitrification efficiencies of about 70% only. The organic compounds contained in the NF permeate were found to temporarily inhibit the nitrifiers (causing nitrite accumulation), whereas the ammonia removed in the clay beads-packed FBR was transformed almost entirely into nitrate. Increase in chloride content did not have any observable detrimental effect on the performance of the reactors. • Salinity effect on performance of nitrifying fixed bed reactors (FBRs) was studied. • Commercial packing materials and loading rates of ca. 1 kg NH 4 +-N∙m-3∙d-1 were used. • FBR with plastic media fed with NF permeate of landfill leachate gave removals >97%. • FBR with clay beads run with synthetic water offered rates of ca. 0.7 kg N∙m-3∙d-1. • Gradual increase in Cl− content from 4 to 16 g/L did not affect reactors' performance. [ABSTRACT FROM AUTHOR]

The aim of present study is to assess the quality of the groundwater at selected villages of Laksar Block on the basis of Water Quality Index (WQI). During the present study maximum value of TS (790.6±28.26 mg/l) was found at site S1, while the minimum value (705.3±5.59 mg/l) was found at site S4. The maximum average value of TDS (548.7±30.37 mg/l) was found at site S5, while the minimum value (352.8±5.59 mg/l) was found at site S4. The maximum average value of pH (7.8±0.58) was found at site S1, while the minimum value (6.9±0.70) was found at site S6. The maximum average value of DO (6.5±0.57) was mg/l found at site S4, while the minimum value (6.1±0.57) was mg/l found at site S6. The maximum average value of TH (396.9±65.94) was mg/l found at site S3, while the minimum value of TH (223.3±5.59mg/l) was found at site S4. The maximum average value of CaH (331.3±32.57mg/l) was found at site S1, while the minimum value of CaH (142.4±2.88mg/l) was found at site S4. The maximum average value of Chloride (137.3±8.72mg/l) was found at site S1, while the minimum Chloride average value (53.4±2.83mg/l) was found at site S4. The maximum value of Sulphate (45.11±0.78mg/l) was found at site S5, while the minimum value (28±2.24mg/l) was found at site S4. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine quantitative and qualitative changes in the waters of Lake Jamno in northern Poland due to the presence of new hydrotechnical structures in its drainage basin, with a special focus on the effects of a new storm barrier. The study consisted primarily of a review of measurement data, historical records and fieldwork prior to the construction (2002–2008) and following the construction of the storm barrier (2015). Fieldwork included hydrographic surveys and water sampling for laboratory analysis. The main and most easily discernible effect of the construction is the change in water quality in Lake Jamno. This is particularly true in the case of key indicators related to seawater, including conductivity, whose values changed from brackish to fresh water. [ABSTRACT FROM AUTHOR]

The provision of safe drinking water is a key driver of public health and a pressing health issue facing First Nations communities in Canada. Contaminated water is a perennial issue for reserve communities across the country despite numerous government investments. Many First Nations communities rely heavily on cistern use for their drinking water supply; however, bacterial contamination within these systems is frequent and a common reason for household boil water advisories. The sources of contamination during the process of hauling water to cisterns in First Nations communities have received limited attention in academic research. The purpose of this research is to identify the risks to water quality through the truck-to-cistern water system. In partnership with a Saskatchewan First Nations community, drinking water quality was monitored in the treatment plant, in delivery trucks and at 142 household cisterns and taps from July to October, 2014. Risks to water supply were identified through monthly water sampling and laboratory analysis, key informant interviews, and observation. Coliform contamination in trucks, cisterns and taps was most common during August. Total coliforms were more likely to be found in cisterns compared to household taps and samples from trucks. Chlorine residuals were lower in household tap samples than in cisterns for August and September. Together with the community, investigators identified contamination and bacteriological growth in cisterns and household distribution systems, and variable levels of total chlorine concentrations depending on month and site of sampling. Recommendations are provided for advancing guidelines on management of truck-to-cistern drinking water supply chains in First Nations. [ABSTRACT FROM AUTHOR]

Surface chloride concentration (SCC) of concrete is an important measure for marine environmental action on oceanic concrete engineering. However, existing models of the SCC could not estimate accurately the chloride attack on concrete exposed to submerged marine environment, as they only involve part of the main influential factors. A quantitative multifactor model for environmental action of submerged marine concrete was developed in terms of the SCC in this study. First, the water‐to‐binder ratio, binder type, chloride concentration of seawater, and exposure time were investigated and adopted as major factors in the computation model of the SCC for submerged marine concrete. The two‐phase multiple nonlinear regression technique was proposed for evaluation of the correction factors for different binder type as well as undetermined coefficients. Then a multifactor computational model for the SCC of submerged marine concrete was developed on the basis of a large number of collected test data. Finally, the effectiveness and advantages of the proposed multifactor model for the SCC were demonstrated by comparison with existing models and test data. [ABSTRACT FROM AUTHOR]

This paper examines the quality of data collected by the Indigenous Observation Network, a community-based water-quality project in the Yukon River Basin of Alaska and Canada. The Indigenous Observation Network relies on community technicians to collect surface-water samples from as many as fifty locations to achieve their goals of monitoring the quality of the Yukon River and major tributaries in the basin and maintaining a long-term record of baseline data against which future changes can be measured. This paper addresses concerns about the accuracy, precision, and reliability of data collected by non-professionals. The Indigenous Observation Network data are examined in the context of a standard data life cycle: plan, collect, assure, and describe; as compared to professional scientific activities. Field and laboratory protocols and procedures of the Indigenous Observation Network are compared to those utilized by professional scientists. The data of the Indigenous Observation Network are statistically compared to those collected by professional scientists through a retrospective analysis of a set of water-quality parameters reported by all three projects over a number of years. No statistical differences were found among the three projects for pH, Calcium, Magnesium, or Alkalinity, although statistically significant differences were found for Sodium, Chloride, Sulfate, and Potassium concentrations. The statistical differences found were small and likely not significant in terms of interpreting the data for a variety of uses. Our results suggest that Indigenous Observation Network data are of high quality, and with consistent protocols and participant training, community based monitoring projects can collect data that are accurate, precise, and reliable. [ABSTRACT FROM AUTHOR]

The process of emulsion separation using an intensifying device tested on the developed mobile well production treatment unit was subjected to quantitative analysis followed by approbation. During tests, cassettes were mounted in the sump of the mobile unit with a distance of 5 mm (standard design) and 2.5 mm between the plates. Experiments were conducted with some variation: with the fluid entering the horizontal sump from the top and from the side, process temperature varying from 60 to 70°C, and with varying fresh water flow rates. It was found that the smaller distance between the plates ensures turbulent diffusion in the intensifying devices, leading to a more intensive oil treatment. It was also found that desalting processes proceed more intensively at 70°С than at 60°C and when fresh water flow rate is increased by 10 and 20%. A 30% increase in the flow rate of fresh water leads to an appreciable increase in the fraction of water in the treated drip oil, the desalting process deteriorates. The study showed that the use of intensifying devices with a distance of 2.5 mm between the plates leads to improved oil treatment: water cut decreased by 2-37% and the content of chloride salts decreased by 5-74% depending on the process. [ABSTRACT FROM AUTHOR]

Bottled drinking water consumption has increased in recent years. Determination of chemical composition of these waters is important interm of public health. Therefore, the objective of the study was to determinenitrate, fluoride, chloride and sulfate levels in bottled waters sold in Sanandajcity during summer and winter of 2012, and their comparison with Iranian and international drinking water standards.Samples were purchased and collected randomly from supermarkets in which 10 types of different brands were examined. The names of the brands are denoted as A to J. The volume of each bottle was 1.5 Lit.Ion Chromatography was used to determine levels of different elements in samples. The results of the study showed that nitrate, fluoride, chloride and sulfate levels in the samples were 0.84-7.69, 0.04-0.32, 0.64-30.29 and 0.26-58.73 mg/l, respectively. levels of nitrate, fluoride, chloride and sulfatein the bottles were lower than drinking water standards, but the written levels on the labels had no enough precision. [ABSTRACT FROM AUTHOR]

The chloride mass balance method of estimating groundwater recharge is generally applied at a point scale but water resources management generally requires information at a regional scale. To estimate groundwater recharge regionally previously used upscaling methods have ranged from simple averaging to empirical relationships and geostatistical interpolation. This study combined the best components of these methods by using regression kriging: in data-sparse areas the recharge is upscaled using global regression equations with gridded rainfall and surface geology as covariates, while in data-dense areas the kriging of the regression equation residuals ensures that the upscaled recharge estimates respect the point estimates of recharge. The uncertainty in the recharge estimates was quantified using 1000 stochastic replicates of the chloride deposition of rainfall, the chloride exported in runoff, the chloride concentration of the groundwater and the regression equations used to perform the upscaling. This study focused on the coal bearing Sydney, Gunnedah, Gloucester and Surat Basins of Eastern New South Wales (Australia). Historically, groundwater recharge to the Permian units of these basins has received little attention due to their low yields of poor quality water. The increased potential extraction of regional groundwater due to coal development has demanded a greater understanding of the water balance. We found that recharge is highest in the younger productive aquifers (up to 20% of long-term mean annual rainfall) and lowest in the Permian units (∼1% of long-term mean annual rainfall). The magnitude of the uncertainty is often close to the magnitude of the median recharge estimate. The method developed here for upscaling the point estimates of recharge using the chloride mass balance provides robust estimates of recharge and its associated uncertainty. The method is applicable to any regional study with variable density input data. [ABSTRACT FROM AUTHOR]

Abstract: The Seymour aquifer consists of unconfined outcrops of sand and gravel in a semiarid, agricultural region of north‐central Texas in the United States of America. Most water samples collected from the aquifer in 2015 had nitrate concentrations above the drinking water standard of 44.3 milligrams per liter (mg/L). Generally, areas with high nitrate concentration in 2010 remained high in 2015, although the median dropped by 3.9 mg/L. The largest decreases in nitrate concentration—up to 97 mg/L (60%)—were observed in wells with depths less than the median of 13.1 meters (m). However, other wells, including depths above and below the median, showed increases in nitrate concentration of up to 40 mg/L (42%). In 2015, chloride concentrations in six wells exceeded the secondary contaminant level of 250 mg/L, and one well had a chloride concentration of 1,810 mg/L. Past and ongoing agricultural practices, including cultivation of native grassland, application of fertilizer, and irrigation with nitrate‐contaminated groundwater, help sustain overall high nitrate concentrations within the aquifer. Local conditions governing nitrogen inputs and dilution result in significant improvement or worsening of the nitrate problem over relatively short timeframes. The pumping of groundwater from the aquifer may facilitate mixing with groundwater of increased salinity that has been affected by the dissolution of evaporites in underlying Permian bedrock. [ABSTRACT FROM AUTHOR]

Abstract: Recent trends of assimilating water well records into statewide databases provide a new opportunity for evaluating spatial dynamics of groundwater quality and quantity. However, these datasets are scarcely rigorously analyzed to address larger scientific problems because they are of lower quality and massive. We develop an approach for utilizing well databases to analyze physical and geochemical aspects of groundwater systems, and apply it to a multiscale investigation of the sources and dynamics of chloride (Cl−) in the near‐surface groundwater of the Lower Peninsula of Michigan. Nearly 500,000 static water levels (SWLs) were critically evaluated, extracted, and analyzed to delineate long‐term, average groundwater flow patterns using a nonstationary kriging technique at the basin‐scale (i.e., across the entire peninsula). Two regions identified as major basin‐scale discharge zones—the Michigan and Saginaw Lowlands—were further analyzed with regional‐ and local‐scale SWL models. Groundwater valleys (“discharge” zones) and mounds (“recharge” zones) were identified for all models, and the proportions of wells with elevated Cl− concentrations in each zone were calculated, visualized, and compared. Concentrations in discharge zones, where groundwater is expected to flow primarily upwards, are consistently and significantly higher than those in recharge zones. A synoptic sampling campaign in the Michigan Lowlands revealed concentrations generally increase with depth, a trend noted in previous studies of the Saginaw Lowlands. These strong, consistent SWL and Cl− distribution patterns across multiple scales suggest that a deep source (i.e., Michigan brines) is the primary cause for the elevated chloride concentrations observed in discharge areas across the peninsula. [ABSTRACT FROM AUTHOR]

Santiago del Estero is a province located in northwestern Argentina. The Dulce River is used for irrigation through a vast network of channels and ditches, including the San Martin Canal (SMC), which crosses the capital city of Santiago del Estero. This canal's water is used for drinking, as well as recreational use for the general population. However, this river has been seriously polluted for several decades. The present study focuses on the identification and the quantification of the water pollution levels of total phenols in the SMC according to the seasonal periods. Water samples from various areas of the canal in different months of the year, extending from December to September, were collected for analysis. Additionally, the concentration of total dissolved solids (TDS), chlorides, sulphates, nitrites and organic matter, as well as water hardness and alkalinity, were analysed in order to conduct a more complete study of the contamination of this area. The results showed a worrying total phenol concentration that exceeded the limit set by Argentine legislation for drinking water, as well as water for recreational use (5 μg/L). The total phenol (TP) concentration was directly determined by a molecular absorption spectroscopy method based on a new flow injection analysis system (FIA). Under the selected experimental conditions, the detection and quantification limits were 0.0490 and 0.1633 μg/mL, respectively. The developed method provides a number of improvements related to the speed of analysis, the restricted consumption of the reagents and sample volumes and the unnecessary sample treatment that contribute to environmentally friendly analytical chemistry. The results showed that TP make a significant contribution in the SMC pollution, especially during the months of April (400 ± 110 μg/L) and September (240 ± 20 μg/L). A high sulphate concentration that was higher than the limit allowed by the legislation was also found. [ABSTRACT FROM AUTHOR]

Chlorine is geochemically stable and is widely used as a groundwater tracer. Stable isotopes of chlorine ( 35 Cl and 37 Cl) are fractionated by diffusion and are used to characterize diffusion-dominant systems, understand seawater intrusion and identify the origin of chlorine. However, a method for measuring the fractionation factor by diffusion (α = D Cl−35  / D Cl−37 ) has not been established for rock samples. We propose a method for measuring α using a conventional through-diffusion experiment, in which a sample is embanked by a high- to low-concentration tank. This study shows that theoretically, the diffusive flux in a through-diffusion experiment should have mass ratio fractionated by diffusion and that the difference between δ 37 Cl in the high- to low-concentration tank will approach to 10 3 ln α with time. The results of the through-diffusion experiment showed a significant difference between δ 37 Cl in the high- and low-concentration tanks. Measured α ranged from 1.0015–1.0022, which is in good agreement with previous studies. Moreover, the sampling period and correction method are suggested to determine α excluding errors due to an unsteady state. The proposed method is applicable to other isotopes to measure α and will contribute to a more quantitative evaluation of Cl and δ 37 Cl profiles. [ABSTRACT FROM AUTHOR]

A new submersible probe for the in situ detection of nitrate, nitrite, and chloride in seawater is presented. Inline coupling of a desalination unit, an acidification unit, and a sensing flow cell containing all-solid-state membrane electrodes allows for the potentiometric detection of nitrate and nitrite after removal of the key interfering ions in seawater, chloride and hydroxide. Thus, the electrodes exhibited attractive analytical performances for the potentiometric detection of nitrate and nitrite in desalinated and acidified seawater: fast response time (t95 < 12 s), excellent stability (long-term drifts of <0.5 mV h-1), good reproducibility (calibration parameter deviation of <3%), and satisfactory accuracy (uncertainties <8%Diff compared to reference technique). The desalination cell, which can be repetitively used for about 30 times, may additionally be used as an exhaustive, and therefore calibration-free, electrochemical sensor for chloride and indirect salinity detection. The detection of these two parameters together with nitrate and nitrite may be useful for the correlation of relative changes in macronutrient levels with salinity cycles, which is of special interest in recessed coastal water bodies. The system is capable of autonomous operation during deployment, with routines for repetitive measurements (every 2 h), data storage and management, and computer visualization of the data in real time. In situ temporal profiles observed in the Arcachon Bay (France) showed valuable environmental information concerning tide-dependent cycles of nitrate and chloride levels in the lagoon, which are here observed for the first time using direct in situ measurements. The submersible probe based on membrane electrodes presented herein may facilitate the study of biogeochemical processes occurring in marine ecosystems by the direct monitoring of nitrate and nitrite levels, which are key chemical targets in coastal waters. [ABSTRACT FROM AUTHOR]

A dredging process is essential for the development of harbours and ports, allowing the functional daily operation of the port. The management of dredged material represents a worldwide challenge, especially considering unwanted deposition of material. Because of their chemical, petrographic, mineralogical and homogeneity composition, marine sediments could represent an appropriate raw material for the brick industry, particularly for the production of clay blocks, roofing and ceramic tiles. In this study dredged material from Port of Koper was tested for such use, thus various analyses were carried out in order to determine if the dredged material is environmentally friendly and suitable for use in the brick industry. These included: chemical analysis, mineralogical analysis, particle size analysis, chloride content analysis and tests of firing in a gradient furnace. Furthermore, tests of mechanical properties, as well as tests of the frost-resistance of the samples were carried out. On the basis of the primary analyses and samples prepared in a laboratory, it was confirmed that marine sediments from the Port of Koper, without any additives are only conditionally suitable as a source material for producing brick products, because without additives they exhibit too much shrinkage on drying and firing, as well as high water absorption, this can be improved by the incorporation of suitable additives, for example, virgin clay or other suitable waste material. The approach described herewith can also be followed to assess sediments from other ports and rivers regarding its potential use in clay brick sector. [ABSTRACT FROM AUTHOR]

Corrosion in water-distribution systems is a costly problem and controlling corrosion is a primary focus of efforts to reduce lead (Pb) and copper (Cu) in tap water. High chloride concentrations can increase the tendency of water to cause corrosion in distribution systems. The effects of chloride are also expressed in several indices commonly used to describe the potential corrosivity of water, the chloride-sulfate mass ratio (CSMR) and the Larson Ratio (LR). Elevated CSMR has been linked to the galvanic corrosion of Pb whereas LR is indicative of the corrosivity of water to iron and steel. Despite the known importance of chloride, CSMR, and LR to the potential corrosivity of water, monitoring of seasonal and interannual changes in these parameters is not common among water purveyors. We analyzed long-term trends (1992–2012) and the current status (2010–2015) of chloride, CSMR, and LR in order to investigate the short and long-term temporal variability in potential corrosivity of US streams and rivers. Among all sites in the trend analyses, chloride, CSMR, and LR increased slightly, with median changes of 0.9 mg L − 1 , 0.08, and 0.01, respectively. However, urban-dominated sites had much larger increases, 46.9 mg L − 1 , 2.50, and 0.53, respectively. Median CSMR and LR in urban streams (4.01 and 1.34, respectively) greatly exceeded thresholds found to cause corrosion in water distribution systems (0.5 and 0.3, respectively). Urbanization was strongly correlated with elevated chloride, CSMR, and LR, especially in the most snow-affected areas in the study, which are most likely to use road salt. The probability of Pb action-level exceedances (ALEs) in drinking water facilities increased along with raw surface water CSMR, indicating a statistical connection between surface water chemistry and corrosion in drinking water facilities. Optimal corrosion control will require monitoring of critical constituents reflecting the potential corrosivity in surface waters. [ABSTRACT FROM AUTHOR]

Accurate, efficient, inexpensive, and multi-parameter monitoring of water quality parameters is critical for continued water safety from developed urban regions to resource-limited or sparsely populated areas. This study describes an integrated sensing system with solution-processed pH, free chlorine, and temperature sensors on a common glass substrate. The pH and temperature sensors are fabricated by low-cost inkjet printing of palladium/palladium oxide and silver. The potentiometric pH sensor has a high sensitivity of 60.6 mV/pH and a fast response of 15 s. The Wheatstone-bridge-based temperature sensor shows an immediate response of 3.35 mV/°C towards temperature change. The free chlorine sensor is based on an electrochemically modified pencil lead, which exhibits a stable and reproducible sensitivity of 342 nA/ppm for hypochlorous acid. Such a free chlorine sensor is potentiostat-free and calibration-free, so it is easy-to-use. The three sensors are connected to a field-programmable gate array board for data collection, analysis and display, with real-time pH and temperature compensation for free chlorine sensing. The developed sensing system is user-friendly, cost-effective, and can monitor water samples in real-time with an accuracy of >82%. This platform enables water quality monitoring by nonprofessionals in a simple manner. [ABSTRACT FROM AUTHOR]

Zerovalent iron (ZVI) based technology has been applied to remediate contaminated groundwater and has been paid great attention as an economic alternative. But it is still remains highly challenging to remove chlorinated pollutants such as trichloroethylene (TCE) with ZVI. Low molecular weight carboxylic ligands (formic acid (FA), oxalic acid (OA), and citric acid (CA)) were chosen to study the influence on the performance of ZVI in groundwater, including the morphology of Fe surface and the Fe dissolution. The removal rate of TCE with ZVI in the presence of 30 mM carboxylic groups followed an order of FA > OA > pure water ≅ CA. FA provides protons to promote the surface corrosion and generated more magnetite on the ZVI surface, which was further responsible for a high adsorption of TCE. With the strong complexing ability of OA and CA, passive layers could form dissoluble complexes via a ligand-promoted dissolution process. However, high concentration of OA resulted in Fe oxalate reprecipitated back onto the ZVI surface then inhibited the reactivity of ZVI. The Fe-ligand complexes also have ability to transform TCE depending on their redox properties. It is expected that effectiveness of carboxylic ligands on the ZVI: those low molecular weight carboxylic ligands in groundwater and soil may enhance the reaction efficiency of ZVI by altering the surface characteristics of ZVI. Therefore, the carboxylic ligands could increase the reactivity and the longevity of ZVI. [ABSTRACT FROM AUTHOR]

The concentration of atmospheric tracers in groundwater samples collected from springs and deep wells is, in most cases, the result of a mixture of waters with a wide range of residence times in the ground. Such is the case of an unconfined aquifer recharged over all its surface area. Concentrations greatly differ from the homogeneous residence time case. Data interpretation relies on knowledge of the groundwater flow pattern. To study relatively large systems, the conservative ion chloride and the decaying radiocarbon ( 14 C) are considered. Radiocarbon ( 14 C) activity in groundwater, after correction to discount the non-biogenic contribution, is often taken as an indication of water age, while chloride can be used to quantify recharge. In both cases, the observed tracer content in groundwater is an average value over a wide range which is related to water renewal time in the ground. This is shown considering an unconfined aquifer recharged all over its area under arid conditions, in which a period of greater recharge happened some millennia ago. The mathematical solution is given. As the solution cannot be made general, to show and discuss the changes in water reserve and in chloride and radiocarbon concentration (apparent ages), two scenarios are worked out, which are loosely related to current conditions in Northern Chile. It is shown that tracer concentration and the estimated water age are not directly related to the time since recharge took place. The existence of a previous wetter-than-present period has an important and lasting effect on current aquifer water reserves and chloride concentration, although the effect on radiocarbon activity is less pronounced. Chloride concentrations are smaller than in current recharge and apparent 14 C ages do not coincide with the timing, duration and characteristics of the wet period, except in the case in which recharge before and after the wet period is negligible and dead aquifer reserves are non-significant. The use of chloride concentration in springs as a proxy of chloride concentration in recharge to estimate recharge from atmospheric deposition leads to recharge value larger than the real one and it approaches the wet period recharge. Drawing inferences about radiocarbon data and recharge by the chloride balance method has rarely been taken into account before. It is important to consider the variable aquifer groundwater reserve. Current recharge estimation can be improved by careful selection of groundwater samples, supported by tritium and radiocarbon measurements. [ABSTRACT FROM AUTHOR]

Greater environmental protections and increased public safety are often believed to be synonymous, or at least to go hand-in-hand. Sometimes, however, those two goals are arguably in tension--for example, when the excess application of salt for winter deicing, in combination with other chloride sources, causes elevated chloride concentrations in waterways. Sodium chloride, commonly known as salt, has often played a critical role in human culture, trade, religion, economics, public safety, and even warfare. But it has a complicated legacy that includes potentially serious adverse consequences for human health and the environment, including deteriorated water quality, toxicity to aquatic and benthic organisms, adverse effects on vegetation, and impacts to drinking water supplies. Moreover, environmental chloride concentrations are on the rise, having approximately doubled over the past two decades. Hundreds of scientific studies have examined potential risks to human health and the environment associated with excess chlorides in the environment, especially those sourced from deicing operations. Yet little, if any, of that work has been directed toward developing legal and policy strategies to address the chloride issue. This interdisciplinary Article examines the underlying causes of unsustainable chloride pollution from a scientific and engineering perspective, and then proposes a menu of responsive legal and policy options. These options include incentivized self-governance at the community or individual levels; informational strategies to encourage optimal chloride use levels for deicing and in water softening applications; direct legal and regulatory mechanisms or mandated best practices issued pursuant to the Clean Water Act, state regulations, or municipal ordinances; use of chloride alternatives such as green infrastructure and substitute deicing substances; integrated watershed management; and direct economic measures. The Article does not suggest that all these options are appropriate in every context, nor does it rank them from most to least useful. Those decisions are left to affected stakeholders. Moreover, the Article does not suggest the elimination of chloride use in its most visible forms (winter maintenance and water softening). Rather, it suggests that such use be optimized. In that spirit, the Article examines the technical and legal contours of each option, and links the scientific underpinnings to the legal and policy dimensions. This approach increases the likelihood that ultimate policy decisions can be both legally defensible and scientifically sound. [ABSTRACT FROM AUTHOR]

The resistance to seawater corrosion was investigated for OPC, CAC, OPC-CAC-gypsum, OPC-SG-FA, and OPC-CAC-gypsum-SG. The specimens were cured in tap water for 28 days and then immersed in artificial seawater for 30, 90, and 180 days. Compressive strength, weight change, apparent porosity, free and total chloride content were measured. The results demonstrated that the compressive strength of all specimens immersed in seawater increased up to 90 days and then decreased up to 180 days. Additional, the compressive strength of CAC immersed in seawater is higher than that in tap water. The OPC-CAC-gypsum-SG system had the highest resistance to seawater corrosion. [ABSTRACT FROM AUTHOR]

The study of groundwater in Amaravathi River basin of Karur District resulted in large geochemical data set. A total of 24 water samples were collected and analyzed for physico-chemical parameters, and the abundance of cation and anion concentrations was in the following order: Na > Ca > Mg > K = Cl > HCO > SO . Correlation matrix shows that the basic ionic chemistry is influenced by Na, Ca, Mg, and Cl, and also suggests that the samples contain Na-Cl, Ca-Cl an,d mixed Ca-Mg-Cl types of water. HCO , SO , and F association is less than that of other parameters due to poor or less available of bearing minerals. PCA extracted six components, which are accountable for the data composition explaining 81% of the total variance of the data set and allowed to set the selected parameters according to regular features as well as to evaluate the frequency of each group on the overall variation in water quality. Cluster analysis results show that groundwater quality does not vary extensively as a function of seasons, but shows two main clusters. [ABSTRACT FROM AUTHOR]