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• 36.5 % of the analysed water samples showed a very good quality. • The highest nitrate levels (>25 mg/L) were observed in the Antela lagoon area. • The main source of nitrates seems be the organic inputs through livestock waste. • A relationship between the accumulated rainfall and nitrate levels in waters was found. • Nitrates were correlated with conductivity (+) and with alkalinity and chlorides (−). The aim of this work was to evaluate monthly the presence of pollutants, especially nitrates, in the Limia river and tributaries in order to evaluate the quality of surface water samples during 2018. An isotopic analysis (δ15N and δ18O) of nitrates was also done with the order to explain the primary sources of nitrate contamination. This area is characterised by intensive use of the soil for potato production over the past 50 years, and has a high livestock load, mainly of pigs. Obtained results show that, in general, water pollution in this area is low with 81.5 % of the samples having all their physicochemical parameters within the category of very good or good quality according to the water quality thresholds. The spatial and temporal distribution of nitrates has shown high variability in the interaction between various factors, such as season and sampling area. Values exceeding 25 mg L−1 of nitrates (moderate quality) were observed in seven samples taken in the Antela lagoon area. Besides, it was observed a relationship between the accumulated rainfall and the concentration of nitrates in surface waters due to the dragging effect from the surrounding land. According to the isotopic results, the primary source of nitrates seems to be the organic inputs to the soil through livestock waste. By applying the discriminant function method, nitrates concentration was correlated positively with the conductivity and negatively with the data of alkalinity and chloride content in waters. Moreover, with principal component analysis, it was possible to separate the water samples by their content in nitrates and other measured contaminants or chemical parameters. [ABSTRACT FROM AUTHOR]

Chlorinated solvents such as tetrachloroethylene (PCE) in aquifers should be remediated due to their toxicity that limited the use of groundwater resources. Nanoscale zero-valent iron (NZVI) and palladized/iron (Pd/Fe) bimetallic particles were synthesized and employed to react with PCE in water to investigate its degradation behaviors. Batch tests were conducted in a 1 L serum bottle under airtight and anaerobic conditions with parameters of Pd mass contents, temperature, pH, and dispersant. The results showed that specific reaction rate constants (kSA) of 5 mg L-1 PCE degraded by metal particles at 30°C in the absence of dispersant enhanced with higher Pd mass contents on the Pd/Fe particles. Degradation rates of PCE increased as the reaction temperature was raised from 20 to 40°C. Carboxymethyl cellulose (CMC), a dispersant, enhanced the kSA values of NZVI and 1:100 Pd/Fe particles by a factor of about 33 and 4 at 30°C, respectively. The tests of pH control with buffer solution indicated that PCE degradation rates were promoted under acid and neutral conditions. Additionally, no chlorinated by-products were observed during the experimental period in each test. This study shows that effective dechlorination of PCE in water could be achieved by synthesized Pd/Fe and NZVI particles coupled with CMC dispersant. [ABSTRACT FROM AUTHOR]

The article offers several suggestion for pond maintenance for small and large pond; larger lakes and larger fountains including avoiding the use of harmful chemicals to avoid pollution; need to clean or backwash pump filters to reduce stress on pump motors; and maintenance of chlorine level.

The article presents a science experiment to help undergraduate chemistry students learn the concepts in determining the potentiometric chloride in natural water. It states the safety considerations, methods of preparation and procedures. Moreover, it mentions that tiltration of data can also be used in determining the resulting precipitant on the chemical reaction between the titrant and analyte.

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]

• Altered whole rock samples lack enrichment in chloride-transported metals. • There are minor anomalies of bisulfide-complexed close to the surface. • Few high-temperature (>300 °C) samples contain scarce muscovite compositions. • Magmas in the TVZ provide mainly heat to the hydrothermal system. The Taupō Volcanic Zone, New Zealand, is one of the most voluminous volcanic regions on Earth. Over the last 1.8 Myr, bimodal volcanism in this rifted-arc setting has been dominated by voluminous rhyolite ignimbrite eruptions (>6000 km3 cumulative) and minor arc-type andesite and dacite, underpinned by basaltic intrusions. The combination of the magmatism and extensionally thinned arc crust with high heat flow has resulted in more than 23 active geothermal fields in the region. The fluids sampled in the geothermal systems are dominated by dilute meteoric fluids that are low in components such as acids, alkalis, and some trace metals commonly ascribed to magmatic sources but can contain large amounts of deep sourced magmatic volatiles such as CO 2. This study was designed to assess the long-term (>20,000yr) fluid and metal input into two Taupō geothermal systems, and the amount and proportion of magmatic-derived components in these fluids. We collected major and trace element compositions of hydrothermal altered whole rocks and clay minerals from two active geothermal systems and compared them with hydrothermally altered rocks of the fossil (0.6 Ma) Ngatamariki magmatic-hydrothermal system, which has a demonstrated large magmatic contribution. The Ohaaki and Rotokawa geothermal systems have both been drilled to a depth of 3000 m, with sampled reservoir fluids containing low concentrations of chloride (∼1000 mg/kg) but high levels of gas (CO 2 , N 2) that have previously been interpreted to reflect subduction components derived from arc-type magmas. Whole-rock samples lack enrichment in chloride-transported metals such as Cu, Pb or Zn but have minor anomalies of bisulfide-complexed Au, Sb, and As in the uppermost 1500 m of the geothermal reservoirs. Hydrothermal water-rock interactions in the deep reservoirs of both geothermal systems at temperatures between 220 and 300 °C produced assemblages of illite + albite + adularia + calcite + pyrite that are in equilibrium with the observed neutral to slightly acidic pH (6 ± 1) of the present-day fluids. In the lower temperature end of this range, Mg and Fe increasingly enter the illite crystal lattice via Tschermak-type (phengite) substitution, whereas a few high-temperature (>300 °C) samples contain scarce muscovite compositions. The illites commonly have low contents of most trace metals, although minor amounts of Cs, Li, Cu, Sb and Sn occur in near-surface samples. Based on these data, over the >20,000-year lifetime of the Ohaaki and Rotokawa geothermal systems, fluids were dominated by chloride-poor meteoric water and contained little magmatic contributions other than conducted heat, some gases (CO 2 - N 2 ± H 2 S), and a small fraction of the total H 2 O of geothermal waters. Therefore, the inferred magma bodies of intermediate to silicic composition that lie at shallow depth beneath these geothermal systems currently are not, and likely have not been for >20,000 years, degassing significant water and chloride despite the high water and chloride contents of the magmas. By inference, the intermediate to silicic magmas at depth have not transferred large amounts of volatiles to the geothermal systems over this period, and rather are storing them in the magmatic bodies to be released in volcanic eruptions that are commonly explosive and pyroclastic in nature and highly hazardous. [ABSTRACT FROM AUTHOR]

The combined geothermal discharge from over 10,000 features in Yellowstone National Park (YNP) can be can be estimated from the Cl flux in the Madison, Yellowstone, Falls, and Snake Rivers. Over the last 30 years, the Cl flux in YNP Rivers has been calculated using discharge measurements and Cl concentrations determined in discrete water samples and it has been determined that approximately 12% of the Cl flux exiting YNP is from the Snake River. The relationship between electrical conductivity and concentrations of Cl and other geothermal solutes was quantified at a monitoring site located downstream from the thermal inputs in the Snake River. Beginning in 2012, continuous (15 min) electrical conductivity measurements have been made at the monitoring site. Combining continuous electrical conductivity and discharge data, the Cl and other geothermal solute fluxes were determined. The 2013–2015 Cl fluxes (5.3–5.8 kt/yr) determined using electrical conductivity are comparable to historical data. In addition, synoptic water samples and discharge data were obtained from sites along the Snake River under low-flow conditions of September 2014. The synoptic water study extended 17 km upstream from the monitoring site. Surface inflows were sampled to identify sources and to quantify solute loading. The Lewis River was the primary source of Cl, Na, K, Cl, SiO 2 , Rb, and As loads (50–80%) in the Snake River. The largest source of SO 4 was from the upper Snake River (50%). Most of the Ca and Mg (50–55%) originate from the Snake Hot Springs. Chloride, Ca, Mg, Na, K, SiO 2 , F, HCO 3 , SO 4 , B, Li, Rb, and As behave conservatively in the Snake River, and therefore correlate well with conductivity (R 2 ≥ 0.97). [ABSTRACT FROM AUTHOR]

The influence of bulk resistivity on the kinetics of chloride-induced macro-cell corrosion of reinforcement was experimentally studied. It was found that the corrosion process was limited by a combination of anodic, ohmic and cathodic control for the geometrical conditions tested (anodes Ø 6 mm, cathode-to-anode ratio 685). The cathodic partial process was independent of the bulk resistivity. Both the anodic and the ohmic partial processes were influenced by local conditions around the anode but were not directly related to the bulk resistivity. The findings indicate that a unique relationship does not exist between bulk concrete resistivity and the corrosion rate. [ABSTRACT FROM AUTHOR]

The effect of wet-dry cycles in tap water and in 3.5% NaCl solution on the passivating products of galvanized steel after concrete carbonation was investigated. The results show that carbonation destroys the passivating layer of calcium hydroxyzincate with the formation of the amorphous products ZnCO3 and Zn5(CO3)2(OH)6, which are also protective. The exposure to wet-dry cycles in tap water after concrete carbonation does not significantly increase the corrosion rate of the galvanized steel with respect to the values measured in non-carbonated concrete. On the contrary, the exposure to chloride solution after concrete carbonation leads to a marked decrease in the chloride threshold for galvanized steel corrosion with respect to that found in non-carbonated concrete. [ABSTRACT FROM AUTHOR]

The objective of the investigation was to analyze the hydro-chemical characteristics of the underground water streams from the northern area of the province of Granma for irrigation use in agriculture. Based on the database available at the National Institute of Hydraulic Resources consisting of 303 wells, it was possible to generate through the Surfer program (version 9.0) hydro-chemical maps on scale of 1:250 000. The maps represent the mineralization, the chloride content, the water chemical class, irrigation coefficient and the marine salinity index. An integral analysis of these maps allowed zoning the hydro-chemical quality of the underground water. The analysis indicates the water streams from the southeast to the area under investigation to be of a higher quality for irrigation purposes. [ABSTRACT FROM AUTHOR]

We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2-·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD-1 at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment. [ABSTRACT FROM AUTHOR]

• The failure analysis of a cast superduplex stainless steel valve has been performed. • The valve failed in proximity of a bar welded on a cast body. • Segregated areas with different PREN in ferritic phase has been found. • The segregated area is less noble and corrodes preferentially. • The cast material showed severe pitting corrosion in immersion tests at 60 °C. This work deals with the failure analysis of a super duplex valve operating in technical waters with high chlorides content up to 80 °C. A careful fracture surfaces and microstructural characterization was combined with corrosion studies (SKPFM (Scanning Kelvin Probe Force Measurements) and polarization curves) of different valve regions in order to determine the failure mechanism. It was found that the cast material presents a segregated microstructure containing ferritic phases with different PREN (Pitting Resistance Equivalent Number). This strongly affects the corrosion properties of the material, enhancing the susceptibility to localized corrosion and leading to SCC (Stress Corrosion Cracking) failure. [ABSTRACT FROM AUTHOR]

Abstract: Water resources in the Middle East, particularly in Palestine, are extremely scarce and costly. The Jordan Valley is a fertile productive region, described as the food basket of Palestine. Groundwater originating from the Quaternary Aquifer System forms the main water resource in the Jordan Valley. However, the quality of this groundwater is threatened mainly by the high chloride concentration. The most representative area of the Jordan Valley is Jericho area, which was chosen to be the study area. The study area (65km2) is almost a flat area with a gentle decline towards the east. It is the lowest land on earth with ground levels reaching 400meters below sea level (mbsl) near the Dead Sea shores. The Quaternary Aquifer System in the study area could be divided into an upper alluvial layer with thickness varying from 40 to 150m and a lower low-permeable Lisan layer, which crops out in the eastern part of the study area with thickness over 200m. Hydrogeochemical investigation reveals that the water is generally earth alkaline with higher content of earth alkalis and prevailing chloride. According to Stuyfzand (1986) and Piper’s (1944) classification systems, water type in the Alluvial Aquifer varies from fresh hard CaMgHCO3 or MgCaHCO3 water in the west and northwest to brackish very-hard MgNaCl or NaMgCl in the middle. In the east, the water becomes brackish-salt extremely-hard MgNaCl or NaCl. Groundwater quality is deteriorating (increase in salinity) spatially towards the east and vertically with increasing depth (when nearing the Lisan Formation). As an indication of groundwater salinity, total dissolved solids show some variability with time over the last 21years (1983–2004). In short-time scale, there are high seasonal and yearly fluctuations with regard to salinity, specifically in Cl− and contents. Spring water from the Upper Cenomanian Aquifer (CaHCO3) represents the fresh end member, while Rift Valley Brines (RVB-CaNaCl) and Dead Sea Brines (DSB-MgNaCl) represent the saline end members. Existing water types are mixtures of the 3 end members. There is a consistency in results and analysis of geological, hydrogeological, hydrochemical and geophysical data. There are three probable sources of increase in groundwater salinity: mixing with saline end members (RVB/DSB); dissolution of minerals of the Lisan Formation (calcite, dolomite, gypsum and halite); and to some extent, agricultural effluent pollution. [Copyright &y& Elsevier]

• A generic framework is presented for studying recharge processes at field scales. • Piston flow is dominant during soil water infiltration in loess tableland. • The tritium peak method can still be used in loess unsaturated zones. • The groundwater in Xifeng tableland is tritium-free. The corrected 14C age ranges from 220 to 19,220 years. Characterization of the rainfall infiltration mechanism, whether piston or preferential flow, through an unsaturated zone is necessary for groundwater resource assessment and for analysis of environmental geological hazards. However, several limitations and difficulties remain in determining the infiltration mechanism in arid and semiarid areas. This study combines the evaluations of soil water infiltration characteristics, recharge rate, and determination of groundwater age at a water table in a semiarid loess tableland to examine the recharge processes. The case study is the Xifeng loess tableland in the Loess Plateau of China, which has an unsaturated zone depth of 40–75 m and an obvious 1963-3H peak at a depth of 7.5 m. According to the piston flow, the soil water infiltration velocity is 0.12–0.14 m/yr, corresponding to a recharge rate of 37–41 mm/yr, based on the 1963-3H peak and chloride mass balance method. All of the groundwater from the water table and wells is old (tritium-free), with ages ranging from hundreds of years to 20,000 years, which suggests that no rapid modern recharge has occurred since the 1950s. The chloride content of soil water in the deep unsaturated zone, with an average value of 10.8 mg/L in the unsaturated zone below 30 m, overlaps with that in groundwater, at 4.0–10.9 mg/L. The comprehensive isotopic and chemical compositions for soil water and groundwater showed that piston flow was dominant during soil water infiltration at the field scale, resulting in the delay of modern water and related solutes entering the groundwater. Combined evaluations of the unsaturated zone with those of the saturated zone and the use of multiple environmental tracers, such as Cl, Br, 2H, 18O, 13C, 3H and 14C, can be regarded as a generic framework for studying the recharge processes in arid and semiarid areas with thick unsaturated zones at macroscopic and field scales. [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]

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 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]

Imidazole-based compounds are used as reagents for the manufacturing of other compounds including imidazolium-based ionic liquids, which have been recently proposed as a green alternative to conventional solvents. Since some imidazole-based compounds have been demonstrated to be harmful to aquatic organisms, the removal of imidazole, 1-methylimidazole, 1-ethyl-3-methyl-imidazolium chloride and 1-butyl-3-methyl-imidazolium chloride from aqueous solutions was attempted by biological oxidation, direct UV 254 photolysis, and UV 254 /H 2 O 2 process at pH 5.5 and 8.5. Results showed that UV 254 /H 2 O 2 treatment is an effective tool for the removal of the selected compounds at both pHs. In fact, the kinetic constants of the reaction between the photogenerated HO radicals and the four target compounds, estimated by means of both numerical and competition kinetic method, range between 2.32·10 9 M −1 s −1 and 5.52 ·10 9 M −1 s −1 . Moreover, an ecotoxicity assessment of the contaminated water before and after initial treatment without further processing was assessed by using two living aquatic organisms: Raphidocelis subcapitata and Daphnia magna . The results of this assessment not only corresponded closely to previous findings (in terms of EC 50 values) reported in the literature, but also indicated that, in some cases, UV 254 /H 2 O 2 oxidation by-products could be even more toxic than parent compounds. [ABSTRACT FROM AUTHOR]

The prediction of proper repair times for reinforced concrete structures in marine environments is an important task for structural maintenance and safety. Chloride attack is the primary threat to marine reinforced concrete structures. Chloride attack can be expressed using a diffusion equation based on Fick's second law. However, for structures that are strongly affected by the shape of the structural sections, or in the case of a surface with repaired concrete, one-dimensional analytical solutions are not sufficient for predicting long-term chloride ion penetration because of shape effects and domain discontinuity. The purpose of this study is to predict the proper repair time of reinforced concrete structures in marine environments that are exposed to long-term chloride attack. In this research, a chloride attack simulation program involving application of a two-dimensional finite difference method was developed to predict chloride ion penetration. Each discretized element of the finite difference method was implemented as an object to allow us to store the required parameters and to calculate the chloride content value independently in order to enable simulation of the discontinuity of the problem domain. The simulation program was applied to the Saemangeum tide gate bridge piers, and the results are presented herein. The results show that the deterioration of steel bars in marine reinforced concrete structures is strongly affected not only by the concrete material but also by the shape of the structures. [ABSTRACT FROM AUTHOR]

Electrochemical processes have been extensively investigated for the removal of a range of organic and inorganic contaminants. The great majority of these studies were conducted using nitrate-, perchlorate-, sulfate-, and chloride-based electrolyte solutions. In actual treatment applications, organic and inorganic constituents may have substantial effects on the performance of electrochemical treatment. In particular, the outcome of electrochemical oxidation will depend on the concentration of chloride and bromide. Formation of chlorate, perchlorate, chlorinated, and brominated organics may compromise the quality of the treated effluent. A critical review of recent research identifies future opportunities and research needed to overcome major challenges that currently limit the application of electrochemical water treatment systems for industrial and municipal water and wastewater treatment. Given the increasing interest in decentralized wastewater treatment, applications of electrolytic systems for treatment of domestic wastewater, greywater, and source-separated urine are also included. To support future adoption of electrochemical treatment, new approaches are needed to minimize the formation of toxic byproducts and the loss of efficiency caused by mass transfer limitations and undesired side reactions. Prior to realizing these improvements, recognition of the situations where these limitations pose potential health risks is a necessary step in the design and operation of electrochemical treatment systems. [ABSTRACT FROM AUTHOR]

The morphologies and phase transitions of waxy cornstarch in solvent mixtures of ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl) and water were systematically studied, combining microscopic observation with SEM and DSC measurements. In pure AMIMCl at room temperature (25 °C), starch granules were gradually dissolved over time; the dissolution process was completed in 52 h. With the presence of water in the solvent mixture, dissolution of starch was obviously delayed and even inhibited. During the heat-dispersed process of starch in solvent mixtures of AMIMCl/water at various ratios, starch dissolution and gelatinization occurred simultaneously, depending on the ratio. After 7 days of storage, no apparent retrogradation was observed, as evidenced in the DSC measurements, and the correlations within the double helices of the gelatinized starch were considered to be permanently eliminated in the presence of a large amount of AMIMCl. [ABSTRACT FROM AUTHOR]

Without claiming to achieve an integrated monitoring or intensive activities for the quality of surface water in the investigated area, this paper aims to assess the quality of water from Bega and Timiş rivers with regard to nitrites, nitrates and chlorides. This is part of a larger study on the quality of water sources in the region, with regard to the anionic and cationic pollutants. The study follows the impact of the drinking water on the human health, especially children and pregnant women. The considered parameters were below the admitted value, therefore no pollution problems were found. [ABSTRACT FROM AUTHOR]

The WASP 7.4 model was applied to the Tumaque basin (Lara and Yaracuy states, Venezuela), to evaluate contaminant dispersion. The geographical characterization of the basin was made considering spot and diffuse sources for sampling points with the aid of Google Earth. Physical, chemical and biological characterization of the waters was carried out. For the hydrodinamic model, the water body was divided into 12 cells. The calibration was performed using two tracers: total dissolved solids and chlorides. The differences between determined and predicted values was 6% when dissolved solids is used as a tracer for the control point at Entrada al Eneal. [ABSTRACT FROM AUTHOR]

Abstract: Disinfection of swimming pool water is essential to deactivate pathogenic microorganisms. Many swimming pools apply chlorine or bromine based disinfectants to prevent microbial growth. The chlorinated swimming pool water contains higher chlorine residual and is maintained at a higher temperature than a typical drinking water distribution system. It constitutes environments with high levels of disinfection by-products (DBPs) in water and air as a consequence of continuous disinfection and constant organic loading from the bathers. Exposure to those DBPs is inevitable for any bather or trainer, while such exposures can have elevated risks to human health. To date, over 70 peer-reviewed publications have reported various aspects of swimming pool, including types and quantities of DBPs, organic loads from bathers, factors affecting DBPs formation in swimming pool, human exposure and their potential risks. This paper aims to review the state of research on swimming pool including with the focus of DBPs in swimming pools, understand their types and variability, possible health effects and analyze the factors responsible for the formation of various DBPs in a swimming pool. The study identifies the current challenges and future research needs to minimize DBPs formation in a swimming pool and their consequent negative effects to bathers and trainers. [Copyright &y& Elsevier]

Dairy waste lagoons are considered to be point sources of groundwater contamination by chloride (Cl−), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl− and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy lagoons and the spatial variability in Cl− and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy lagoons in this region (0.8%), leachates from lagoons have contributed 6.0% and 12.6% of the total mass of Cl− and TN (mainly as ) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl− and TN to the groundwater. A low spatial correlation between the Cl− and concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl− and . Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the lagoons would decrease the regional groundwater salinization process (11% of the total Cl− load is stored under lagoons). A more considerable reduction in the groundwater contamination by is expected (25% of the load is stored under lagoons). Results demonstrate that analyzing vadose zone and groundwater data by spatial statistical analysis methods can significantly contribute to the understanding of the relations between groundwater contaminating sources, and to assessing appropriate remediation steps. [Copyright &y& Elsevier]

The reaction of phosphor-containing pesticides such as methidathion (MT) and dimethoate (DM) with dichloride radical anions was investigated. The second order rate constants (1.3 ± 0.4) × 108 and (1.1 ± 0.4) × 108 M−1 s−1 were determined for the reaction of cl˙-2 with MT and DM, respectively. A reaction mechanism involving an initial charge transfer from the sulfide groups of the insecticides is proposed and supported by the identified transient intermediates and reaction products. The formation of chlorinated byproducts was determined. The unexpected consequences of an efficient cl˙-2 reactivity towards MT and DM on the degradation capacity by Advanced Oxidation Procedures applied to polluted waters containing the insecticides and Cl− anions is discussed. [Copyright &y& Elsevier]

Abstract: Groundwater, surface water, and soil in the Goose Lake oil field in northeastern Montana have been affected by Cl−-rich oil-field brines during long-term petroleum production. Ongoing multidisciplinary geochemical and geophysical studies have identified the degree and local extent of interaction between brine and groundwater. Fourteen samples representing groundwater, surface water, and brine were collected for Sr isotope analyses to evaluate the usefulness of 87Sr/86Sr in detecting small amounts of brine. Differences in Sr concentrations and 87Sr/86Sr are optimal at this site for the experiment. Strontium concentrations range from 0.13 to 36.9mg/L, and corresponding 87Sr/86Sr values range from 0.71097 to 0.70828. The local brine has 168mg/L Sr and a 87Sr/86Sr value of 0.70802. Mixing relationships are evident in the data set and illustrate the sensitivity of Sr in detecting small amounts of brine in groundwater. The location of data points on a Sr isotope-concentration plot is readily explained by an evaporation-mixing model. The model is supported by the variation in concentrations of most of the other solutes. [Copyright &y& Elsevier]

Abstract: Fluoride bioaccumulation in the signal crayfish Pacifastacus leniusculus (Dana) was examined through field and laboratory studies, considering in the latter the effects of several biotic and abiotic factors: water chloride content, developmental stage, sex, and tissue. The potential use of P. leniusculus as bioindicator of fluoride pollution in freshwater ecosystems was also assessed by testing the capability of juvenile crayfish to release fluoride during depuration periods. After discussing the obtained results, we concluded that: (1) fluoride pollution by industrial effluents may significantly increase the fluoride content in signal crayfish inhabiting polluted freshwater ecosystems; (2) although high chloride levels in the aquatic medium may significantly reduce the fluoride content in signal crayfish exposed to fluoride pollution conditions, fluoride bioaccumulation can still occur in significant amounts; (3) sex does not seem to be an important biotic factor affecting fluoride bioaccumulation in signal crayfish; (4) in contrast, the type of tissue is an important biotic factor affecting fluoride bioaccumulation in signal crayfish, with the exoskeleton accumulating more fluoride than the muscle, in absolute terms, but with the muscle accumulating more fluoride than the exoskeleton, in relative terms (in relation to pre-effluent/control values); (5) the developmental stage seems to be another important biotic factor affecting fluoride bioaccumulation in signal crayfish, with juveniles being able to accumulate fluoride more rapidly than adults under fluoride pollution conditions; (6) although, during depuration periods, signal crayfish may significantly release fluoride, they can still retain significant amounts of the fluoride previously bioaccumulated during exposure periods. We can overall conclude that fluoride bioaccumulation in signal crayfish may be used as suitable bioindicator of fluoride pollution in those freshwater ecosystems where it is already present. However, this notable capability to accumulate and retain fluoride poses a potential risk to human health when signal crayfish from fluoride polluted areas are consumed. [Copyright &y& Elsevier]

Abstract: Aquatic biota living in urban watersheds, are chronically exposed to a complex mixture of contaminants from various sources, including municipal wastewater effluents and road runoff. This study examined the general condition, immune function and contaminant load of wild freshwater mussels collected from a large urbanized river over three consecutive field seasons. Four study sites along the Grand River (ON) were selected to represent an incremental contaminant exposure, such that mussels collected from the final downstream site were exposed to the cumulative inputs from 11 municipal wastewater treatment plants and road runoff from four cities. Wild mussels collected downstream of the urban area had significantly lower (p <0.05) condition factor and did not live as long (significantly reduced mean age) as the mussels collected upstream of the cities. There appears to be a trend of increasing proportions of gravid females at the downstream sites, but whether this trend indicates feminization of the mussel population or is simply an artifact of sampling effort is unclear. An examination of hemocyte phagocytosis revealed a pattern of increasing immune activity at the downstream sites, but only in one of the years sampled. The significant and cumulative increase in Cu, Pb, Zn, Al, Cr, and Ni in the gills of downstream mussels indicates that metals are bioavailable in this ecosystem and that tissue concentrations increase with multiple urban inputs. While the complex nature of the exposure prevents identification of the cause(s) of the observed effects, some contaminants such as ammonia and chloride reach levels known to be toxic to freshwater mussels at the downstream sites. These results indicate that chronic exposure to multiple contaminants negatively impacts mussel health and longevity and corroborates previous assumptions that waterborne contaminants contributed to the decline of the freshwater mussel populations in this watershed. [Copyright &y& Elsevier]

Guha, Hillol and Sorab Panday, 2012. Impact of Sea Level Rise on Groundwater Salinity in a Coastal Community of South Florida. Journal of the American Water Resources Association (JAWRA) 48(3): 510-529. DOI: 10.1111/j.1752-1688.2011.00630.x Abstract: Freshwater resources of coastal communities in the United States and world over are threatened by the rate of sea level rise. According to recent estimates by various governmental agencies and climate researchers, the global sea level rise is likely to be between 0.6 and 2.1 m by the year 2100. South Florida is a coastal community and much of its coastline is subject to sea level rise and potential impacts to wetlands and the water resources of the area. To understand what the impact of sea level rise would cause to the groundwater level and salinity intrusion, an integrated groundwater and surface water model was developed for North Miami-Dade and Broward Counties of South Florida. The model was calibrated against daily groundwater heads, base flows in canals, and chloride concentrations for a period of one year and six months. Three separate sensitivity analyses were conducted by increasing the sea level by 0.6, 0.9, and 1.22 m. Results of the simulations shows increase of groundwater heads in some areas from 4 to 15%; whereas the average relative chloride concentrations increased significantly by 100-600% in some wells. The increase in groundwater elevations and chloride concentrations varies from location of the wells and its proximity to the coast. The model results indicate that even a 0.6 m increase in sea level (which is the conservative estimate) is likely to impair the vital freshwater resources in many parts of South Florida. [ABSTRACT FROM AUTHOR]

Abstract: Water treatment processes can cause secondary changes in water chemistry that alter finished water quality including chloride, sulfate, natural organic matter (NOM), and metal release. Hence, the goal of this research was to provide an improved understanding of the chloride-to-sulfate mass ratio (CSMR) with regards to chloride and sulfate variations at full-scale water treatment plants and corrosion potential under simulated premise plumbing conditions. Laboratory corrosion studies were conducted using Pb–Sn solder/Cu tubing galvanic cells exposed to model waters with low (approx. 5 mg/L Cl− and 10 mg/L SO4 2–) and high (approx. 50 mg/L Cl− and 100 mg/L SO4 2–) concentrations of chloride and sulfate at a constant CSMR of ∼0.5. The role of NOM during corrosion was also evaluated by changing the type of organic material. In addition, full-scale sampling was conducted to quantify the raw water variability of chloride, sulfate, and NOM concentrations and the changes to these parameters from magnetic ion exchange treatment. Test conditions with higher concentrations of chloride and sulfate released significantly more lead than the lower chloride and sulfate test waters. In addition, the source of NOM was a key factor in the amount of lead released with the model organic compounds yielding significantly less lead release than aquatic NOM. [Copyright &y& Elsevier]

The antimalarial and cytotoxic activity of the products is evaluated. [ABSTRACT FROM AUTHOR]