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The mobility of arsenic compounds in the soil-plant system and its interaction with biogenic macroelements K, P, Ca, Mg, Si, S, Na in plants under conditions of toxic stress have been studied. This is illustrated by the wheatgrass Elytrigia repens. It has been established that the root system is responsible for protecting the aerial part of wheatgrass from excess arsenic, and it is of great importance for phytostabilisation of arsenic pollution therefore indicating the increased tolerance of this plant. The intensity of As accumulation in plants depends on its speciation in the soil. Antagonism of the main essential elements (K, P) to the accumulation of As in wheatgrass shoots is observed. It can lead to disruption of metabolic processes in plant cells. It has been shown that changes in the K+/Na + values may lead to violation of osmotic processes in the aerial plant organs and contribute to their degradation not only under salt stress but also under the influence of higher concentrations of As in the plants. In areas intensively contaminated with arsenic, a decrease in the K/Na value in the above-ground organs of wheatgrass can be used as a criterion for the degree of phytotoxicity. [ABSTRACT FROM AUTHOR]

From at least the fifteenth to late nineteenth centuries, peasants in the Austrian province of Styria ate up to several hundred milligrams of arsenic trioxide or sulfide daily or weekly for periods up to a number of years. Taking these doses of arsenic was believed to increase muscular power and enhance the beauty and sexual attractiveness of peasant girls. There do not appear to be contemporaneous records of the known consequences of chronic arsenic exposure. The historical records of arsenic eating there are reviewed and appear to be valid. The benefits are subjective judgements by arsenic eaters. The lack of objective reports of the anticipated external and internal clinical and pathological effects of arsenic poisoning depends on a smaller number of clinical accounts and autopsy reports and the general medical literature of those times, so it is weaker, but it is consistent. Why the arsenic eaters did not show the well-known consequences of prolonged exposure to high doses of arsenic is not known. Possible explanations include increases in detoxifying metabolism in the consumers due to induced genomic changes and selection in people and in the gut microbiome, as shown in other populations. Whether these effects would suffice to protect people against their high doses of arsenic has not been explored. Although the nature and mechanisms of arsenic toxicity have been extensively described, much still remains to be discovered. [ABSTRACT FROM AUTHOR]

An analytical method for determination of inorganic arsenic species in retorted oil shale slurry by atomic absorption spectrometry coupled to hydride technique with ultrasound assisted acidic extraction is reported. Trivalent arsenic measurement employed sample stabilization with a pH 4.5 prior to reaction with the reducing agent and analysis. In contrast, total inorganic As depended upon the pre-reduction of As(V) to As(III) with KI and ascorbic acid in 6.0 M HCl and of As(V) was estimated by the difference of the total inorganic As and As(III) concentrations. The limit of quantification was 3.7 mg kg−1 for As(III) and 1.3 mg kg−1 for itAs. [ABSTRACT FROM AUTHOR]

Arsenic is a common pollutant and impurity present in complex gold ores. In the pressure oxidation (POX) of refractory gold-bearing sulfides, a major environmental challenge is the treatment of the hazardous waste released from arsenic-bearing minerals during processing. While the bulk removal of arsenic from solution can occur during POX, the formation of stable arsenates relies on the operating conditions during POX and the subsequent curing stage. Herein, response surface methodology (RSM) and central composite design have been investigated as viable approaches for optimizing arsenic fixation during the curing of the POX product of arsenopyrite. Curing time (0–24 h) and temperature (60–120°C) were examined as the model variables for RSM optimization, and the performance was assessed via arsenic and iron precipitation, along with the change in free acid and sulfate concentrations. Experimental validation of the optimized model conditions demonstrated good agreement with the simulated outputs and provided a 10% increase in arsenic removal over the best model input. The formation of basic ferric arsenate sulfate and scorodite under these conditions was supported by RSM and confirmed via characterization. In the investigated system, the maximum arsenic removal occurs at a critical threshold temperature of 107°C, over which the scorodite formation decreases with temperature. Thermodynamic modeling revealed the preferable formation of soluble FeHAsO4+ complexes over scorodite above this threshold temperature, decreasing arsenic fixation at higher temperatures. [ABSTRACT FROM AUTHOR]

Arsenic is a hazardous heavy metalloid that imposes threats to human health globally. It is widely spread throughout the environment in various forms. Arsenic-based compounds are either inorganic compounds (iAs) or organoarsenicals (oAs), where the latter are biotically generated from the former. Exposure to arsenic-based compounds results in varying biochemical derangements in living systems, leading eventually to toxic consequences. One important target for arsenic in biosystems is the network of metabolic enzymes, especially the superfamily of cytochrome P450 enzymes (CYPs) because of their prominent role in both endobiotic and xenobiotic metabolism. Therefore, the alteration of the CYPs by different arsenicals has been actively studied in the last few decades. We have previously summarized the findings of former studies investigating arsenic associated modulation of different CYPs in human experimental models. In this review, we focus on non-human models to get a complete picture about possible CYPs alterations in response to arsenic exposure. [ABSTRACT FROM AUTHOR]

Arsenic pollution in water sources has been a recurring issue for the nations where groundwater is the sole source of survival. While conventional pressure-driven membrane is the epitome of a water treatment solution, it is not without limitations for arsenic removal. Thus, adsorptive membranes are studied since they combine positive features of adsorption and ultrafiltration technology that makes them able to remove arsenic effectively while offering promising flux. While there are studies reporting on the roles of adsorptive membranes for arsenic removal, there is much to discover on the performance of different adsorptive membranes in terms of adsorption capacity, regeneration potential, and stability. In this review, we survey the characteristics of a wide range of nanoadsorbents focussing on the membrane properties for arsenic removal as well as regeneration process of adsorptive membrane using different solutions. The key challenges faced during membrane fabrication and operation are also highlighted providing a better insight toward development of more robust adsorptive membranes. It is hoped that through this review, researchers will be inspired to develop more functional adsorptive membranes with not only outstanding performance but also stable performance for arsenic removal. [ABSTRACT FROM AUTHOR]

In this study N-methyl-D-glucamine selective functional group is bound to magnetic nanoparticles (M-TACA) with click chemistry, which is fast, simple to use, easy to purify, versatile, region-specific and gives high product yield. The synthesized M-TACA nano-sorbent was characterized by SEM and VSM techniques. The parameters effecting sorption of As(V) onto M-TACA such as dosage, initial concentration of As(V), contact time and pH were studied. Sorption of As(V) onto M-TACA nano-sorbent is pH dependent and the maximum sorption capacity was obtained at pH 6 as 76.54 ± 1.21mg/g. The effects of fluoride, sulfate and phosphate ions, which compete with As(V) to hold active groups, on the sorption of As(V) were investigated. Fluoride has minimal effect on arsenic uptake. It is sulfate that has the most negative effect on intake and phosphorus has had a less negative effect. Sorption is more compatible with the Langmuir isotherm model than any other applied isotherm model. Results obtained from intra particle diffusion model shown the two sorption stages indicating that both surface and intra-particle sorption occurs. At the same time, sorption percentages for five times reusability were determined as 99.6 ± 2.5%, 99.0 ± 3.0%, 98.6 ± 3.1%, 97.0 ± 3.5% and 96.6 ± 3.8%, respectively. The reusability results showed that the MTACA nano-sorbent can be reused at least 5 times in removal of As(V). [ABSTRACT FROM AUTHOR]

A new procedure is reported for arsenic preconcentration in juvenile eyeshadow using maghemite nanoparticles (γ-Fe2O3) and determination by flow injection analysis – hydride generation atomic absorption spectrometry (FIA-HG-AAS). Maghemite nanoparticles were synthesized and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption measurements at −196 °C. The results showed a crystalline size of 9.1 nm and a surface area of 106 m2 g−1. The experimental conditions for the hydride generation system and the preconcentration process were optimized using a central composite design. For hydride generation, the levels of the concentration of the factors HCl, NaBH4, and flow of carrier gas were optimized, with optimal conditions of 4 mol L−1, 1.1% (m/v), and 145 mL min−1, respectively. The optimized conditions obtained for the adsorption process were a pH equal to 5.3, a mass of γ-Fe2O3 of 184 mg, and stirring time of 41 min in the presence of the sample matrix. The enrichment factor was 50, and the limit of detection was 0.9 μg g−1. Recovery values ranged from 75 to 99%. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a chemical element that is widely distributed in the environment. The high content of As in groundwater represents a major public health problem in many regions of the world. According to the World Health Organization, it is one of the tenth chemicals of major public health concern. The consumption of As for long periods of time has been associated with a disease known as Chronic Endemic Regional Hydroarsenicism (CERHA), a serious condition of long evolution that is characterised by skin lesions and cancerous and non-cancerous alterations. Consequently, As measurement is mandatory; therefore in this work is presented the development of a low-cost, not fragile equipment for the spectrophotometric measurement of As that has the advantage of less manipulation of toxic reagents. The analysis of 42 calibration curves was performed indicating an accuracy of 90.38%. The technique has proven to be effective in determining As in water, at low cost, accessible and reliable, allowing the measurement of a large number of samples. Also, great advantages were performed regarding biosecurity. [ABSTRACT FROM AUTHOR]

Arsenic is a heavy metal having great scientific concern due to its toxic effects. Chrysin is a flavone found in honey and plants. This study was designed to evaluate the therapeutic effects of chrysin against arsenic incited nephrotoxicity in rats. Animals were separated into four different groups and designated as control, arsenic (10 mg/kg) treated, arsenic + chrysin (10 mg/kg and 50 mg/kg respectively) treated and chrysin (50 mg/kg) treated groups. After 30 days of trial, rats were dissected and antioxidant enzymes, renal damage markers, inflammatory markers, DNA damage and histopathology were observed. Catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST) activities and glutathione (GSH) content were significantly (p <.05) reduced whereas thiobarbituric acid reactive substance (TBARS) and reactive oxygen species (ROS) levels were significantly (p <.05) increased due to arsenic exposure. Arsenic treatment caused a significant (p <.05) increase in urea, creatinine, urobilinogen, kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) levels while a substantial reduction in creatinine clearance was observed. Arsenic exposure significantly (p <.05) increased the inflammatory markers, including nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6) levels and cyclooxygenase-2 (COX-2) activity. The results demonstrated that arsenic exposure significantly (p <.05) increased the DNA and histopathological damages. However, chrysin treatment significantly (p <.05) restored the damages induced by arsenic. These results revealed that the chrysin is an effective compound, having curative potential to counter the arsenic-induced renal damage. [ABSTRACT FROM AUTHOR]

One of the emerging environmental concerns is the high levels of arsenic ions found in groundwater and other water sources. Decontaminating water that contains arsenic is crucial for environmental and health reasons. Nano-adsorbents have gained much interest recently for the adsorptive removal of arsenic species from wastewater. On the other hand, for their prospective use in natural water treatment, current nano-adsorbents must be separated from treated fluids. Researchers studied nanocomposite iron oxide-based adsorbents to overcome these problems and to design effective sorbents for removing arsenic. This study provides a summary of current developments in the field of magnetic nanoadsorbents for the removal of various arsenic compounds from wastewater. Adsorption of arsenic from groundwater has been found to be very promising for magnetic nanoadsorbents. In order to eliminate arsenic from the aqueous phase, magnetic nanocomposite adsorbents may offer practical and affordable water purification solutions. [ABSTRACT FROM AUTHOR]

Over 300 species of naturally occurring-organoarsenicals have been identified with the development of modern analytical techniques. Why there so many environmental organoarsenicals exist is a real enigma. Are they protective or harmful? Or are they simply by-products of existing pathways for non-arsenical compounds? Fundamental unanswered questions exist about their occurrence, prevalence and fate in the environment, metabolisms, toxicology and biological functions. This review focuses on possible answers. As a beginning, we classified them into two categories: water-soluble and lipid-soluble organoarsenicals (arsenolipids). Continual improvements in analytical techniques will lead to identification of additional organoarsenicals. In this review, we enumerate identified environmental organoarsenicals and speculate about their pathways of synthesis and degradation based on structural data and previous studies. Organoarsenicals are frequently considered to be nontoxic, yet trivalent methylarsenicals, synthetic aromatic arsenicals and some pentavalent arsenic-containing compounds have been shown to be highly toxic. The biological functions of some organoarsenicals have been defined. For example, arsenobetaine acts as an osmolyte, and membrane arsenolipids have a phosphate-sparing role under phosphate-limited conditions. However, the toxicological properties and biological functions of most organoarsenicals are largely unknown. The objective of this review is to summarize the toxicological and physiological properties and to provide novel insights into future studies. [ABSTRACT FROM AUTHOR]

Removal and immobilization of highly toxic arsenic form industrial wastewater using simple and effective methods is of important practical significance. Although the formation of natroalunite phase NaAl3(SO4)2(OH)6 has been demonstrated to be an effective method for arsenic immobilization in model system with chemical reagent grade arsenates as arsenic source, the further study is needed to investigate its immobilization for real industrial wastewater. This work reported the synthesis of natroalunite phase NaAl3(SO4)2(OH)6 using arsenic-containing industrial wastewater from benzyl acid production. The synthesis temperature and time were optimized to obtain the pure natroalunite phase composites with high crystallinity. When n(Al/As)aq was greater than 3.0, the arsenic could almost precipitate exclusively as natroalunite phase after 60 min hydrothermal reaction at 200°C, with a maximum arsenic immobilization amount of 7.0 mol%. A maximum leaching concentration of 0.50 mg/L was observed at pH = 3.0 during the short-term (24 h) leaching test, which was lower than the US EPA TCLP test limit of 1 mg/L. The long-term leaching test up to 90 days revealed that the arsenonatroalunite could be a safe immobilization material for arsenic in pH 5.0–8.0 environments. [ABSTRACT FROM AUTHOR]

North-eastern states of India, including Assam, have a high prevalence of head and neck cancer cases. In these regions, Sadagura is a unique form of smokeless tobacco (SLT). There are fewer reports regarding the effects of simultaneous sadagura and arsenic co-exposure. Analysis of chemical compounds present in sadagura aqueous extract was done using gas chromatography–mass spectrometry. Estimation of arsenic contamination in groundwater and bioaccumulation in human tissues was performed by using atomic absorption spectroscopy. Buccal micronucleus cytome (BMCyt) assay and analysis of various peripheral blood parameters were performed among study volunteers. Chronic exposure (90 days) experiments were performed in mice test system in vivo to determine any possible protective potential of vitamin C (Vit-C) supplementation against sadagura and arsenic co-exposure. BMCyt assay results revealed a higher incidence of micronucleated cells (p < 0.001), and cell death biomarker among sadagura consumers residing in arsenic affected areas. Comet assay of mice femur bone marrow cells following chronic exposure of the test substances revealed a reduction in DNA damage due to Vit-C supplementation. Histological examination of the hepatic and renal tissues revealed marked improvement due to Vit-C supplementation in mice against sadagura and arsenic chronic co-exposure. Indiscriminate consumption, presence of various harmful compounds in sadagura along with arsenic co-exposure might be a vital link for the higher incidence of oral cancer in the region. Chronic Vit-C supplementation study results in mice show its effective remedial potential against combined sadagura and arsenic co-mediated genotoxicity and ultrastructural changes in major organs. [ABSTRACT FROM AUTHOR]

It is very important to develop effective and reusable functional materials for arsenic removal from water. In this study, one carbon fiber nanocomposite mat modified with ceria oxide nanoparticles was successfully prepared by electrospinning. The adsorption performances of the composite for different arsenic species were systematically investigated. The composite possessed good performance for selective adsorption of AsⅤ at pH 12 without obvious coexisting ion interference effects. The adsorption processes fitted well with the quasi-first-order dynamics and Langmuir isotherm models. The composite mat is stable and reusable, and can be easily isolated from water after use. The prepared composites were characterized by scanning electron microscope and energy-dispersive spectroscope (SEM-EDS), x-ray diffraction spectrometry (XRD) and Fourier transform infrared spectrum (FTIR), and the possible adsorption mechanism was also discussed. [ABSTRACT FROM AUTHOR]

The potential application of electrodialysis (ED) for arsenic (As) removal from water was investigated by evaluating the influence of operational parameters on removal efficiency of As. The applied voltage and the initial concentration of As in the feed solution have significant effects on the removal efficiency of As in the transfer As from feed to concentrate compartments. The mass-transfer coefficient is increased with increase in applied voltage, and those of As(V) are always higher than those of As(III). The pH of feed solution has little effect on the mass-transfer coefficients of As(III) and As(V) within the applied voltage range. [ABSTRACT FROM AUTHOR]

Arsenic has been used for various purposes throughout human history, such as medicinal and industrial applications, while its health risks have only been gradually recognized in the 20th century and have raised global concerns since the 1990s. Reviewing the progress of arsenic research from a scientometric viewpoint is of great value and importance to predict future trends in arsenic studies. Unfortunately, such review is lacking, which could possibly lead to a biased understanding of the role of arsenic in human health. In this study, we collected 61,988 published literatures on arsenic research in the past 120 years from Web of Science, on which scientometric analysis using CiteSpace and subsequent review were conducted. Our scientometric-based review demonstrated the progress in the past 120 years of arsenic research and identified emerging trends in recent years, emphasizing the health risks posed by arsenic, arsenic applications, and their interaction. The information summarized in this study will shed light on the wise and extensive use of arsenic, which could be a double-edged sword in human health. [ABSTRACT FROM AUTHOR]

The presence of arsenic in groundwater, eventually in drinking water, has been recognized as a serious community health problem due to its highly toxic nature, and therefore, its removal is highly essential. To enhance the adsorption capacity of chitosan for As (V), chitosan which is a natural biopolymer was modified by grafting with 2-Hydroxyethylmethacrylate (HEMA) and Sodium Styrene Sulfonate (SSS). Modified chitosan was characterized by SEM and FTIR spectroscopy. Maximum Removal percentage of As (V) was found to be higher (95%) at inlet concentration of As (V) 60 mg/L, flow rate 1 ml/min, pH 3.5, and bed depth 3 cm. The bed depth service time model and Thomas model are used to analyze the column data in terms of As (V) uptake rate and column capacities. Developed grafted adsorbent could be successfully regenerated using 0.1 M NaOH. Recycle studies suggested that maximum reusability of grafted polymer up to 8 cycles. [ABSTRACT FROM AUTHOR]

Yellowknife, Northwest Territories, Canada, is located near two closed gold mines. Elevated arsenic concentrations reported in fish are a public health concern. We collected 180 samples of three species of commonly consumed fish in 2013–2018 and analyzed arsenic species, including inorganic arsenic (As(III) and As(V)), monomethylarsonate (MMA), dimethylarsinic acid (DMA), and arsenobetaine. The average total arsenic concentration in fish muscle tissue was 2.30 ± 1.72 µg/g dry weight, and that in burbot liver tissue was 3.16 ± 2.49 µg/g dry weight. Nontoxic arsenobetaine was the main arsenic species in fish muscle (mean = 58.6 ± 34.5%), whereas DMA was the predominant species in burbot liver (mean = 76.6 ± 21.6%). On average, inorganic arsenic species accounted for less than 20% of the arsenic detected in fish. Data on the consumption of locally caught fish were collected from 1611 residents in Yellowknife in 2017 and 2018, including 1417 general residents and 194 members of the Yellowknives Dene First Nation. We evaluated the health risks from inorganic arsenic exposure using Monte Carlo simulations. Our results indicated that there were negligible non-cancer health risks, and the cancer risk was below the baseline cancer risk level of arsenic exposure among the Canadian general population. [ABSTRACT FROM AUTHOR]

A novel bimetallic layered hydroxide (Ca–Fe–Cl LDHs) was prepared for the removal of arsenic (III) (As (III)) from an aqueous solution. The materials were characterized by SEM, XPS, TGA, and FTIR to analyze this removal mechanism. The effects of pH, contact time, dosage, initial concentration, and coexisting anions on the removal of As (III) by Ca–Fe–Cl LDHs were explored. The results demonstrated that Ca–Fe–Cl LDHs exhibited good performance with a maximum adsorption capacity of 22.1 mg/g, and adding 1.26 g/L Ca–Fe–Cl LDHs can reduce the concentration of arsenic solution (0.4 mg/L) to below 0.01 mg/L, and the removal rate of As (III) was not affected within the pH range of 2 − 12. The Langmuir model and the pseudo second-order dynamics model could better fit the experimental data with R2 equal to 0.969 and 0.885, respectively. Coexisting ions, such as HPO42−, SO42−, CO32−, and NO3−could inhibit material adsorption and reduce the removal efficiency of As (III). Under experimental conditions, the concentration of 0.01 M Na2CO3 solution was used for regeneration, and the efficiency of As (III) removal was maintained above 90% after 5 regenerations. [ABSTRACT FROM AUTHOR]

Co-occurrence of arsenic and nitrate in groundwater sources at a wide range of concentrations is reported. In this work, performance of suspended growth semi-batch reactor was assessed for co-removal of arsenic and nitrate from simulated groundwater to meet the drinking water standards in the absence of iron. The bioreactor was inoculated with mixed bacterial culture and operated in the absence of oxygen for more than 450 days under varying influent arsenate (200–800 µg/L), nitrate concentrations (50–250 mg/L), and hydraulic retention time of 3–6 days. Complete nitrate removal was observed at all tested concentrations. Arsenic removal was found to meet drinking water standards from initial concentrations and up to 600 µg/L. The extended toxicity characteristic leaching procedure leaching experiments indicated that arsenic-laden biosolids would not constitute a hazardous waste. The arsenic leaching was found to increase with an increase in dissolved oxygen and the final leachate concentrations of arsenic were below 150 µg/L. The leaching experiments suggested maintaining non-alkaline conditions for minimum arsenic release from arsenic biosolids formed under sulphidogenic conditions. This study is the first to report that nitrate and arsenic can be simultaneously removed to meet drinking standards in a suspended growth bioreactor. [ABSTRACT FROM AUTHOR]

Dietary intake and urinary excretion of monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AsB) were measured in 150 adult Japanese subjects. Duplicate diet (DD) samples and first void of urine on the next morning of DD sampling day were collected and analysed for arsenic species with liquid chromatography-ICP mass spectrometry. Median (min-max) intakes of MMA, DMA and AsB were <2.3 (<2.3-<2.3), 4.57 (<2.3–24.3), and 13.6 (<2.4–231) μg As/day, respectively, and median urinary concentrations were 1.90 (<0.37–26.), 21.9 (<0.27–141) and 19.6 (<0.37–1063) ng As/mg creatinine, respectively. Interrelationships between intake levels and urinary concentrations were mostly significant with positive coefficients indicating mutual association due to co-exposure, metabolism and/or dietary habit. Urinary concentrations and intake levels of AsB were also positively correlated confirming the applicability of urine analysis as biomarker of exposure. The present descriptive results provide with essential piece of information in assessing health risk of methylated arsenicals for population who consume marine products and rice. [ABSTRACT FROM AUTHOR]

Plants used in phytoremediation should accumulate and tolerate a specific pollutant. Here, we aimed at evaluating a possible arsenic (As) accumulation and mechanisms of tolerance against As-induced damage in Landoltia punctata to explore this species for phytoremediation. Plants were subjected to increasing As levels. As absorption was higher with increasing As levels. The activity of superoxide dismutase and glutathione reductase as well as anthocyanin levels increased with As levels. Catalase and peroxidase activities increased in plants subjected to As levels up to 1.0 mg L−1 and decreased at higher levels. Due to the antioxidant system, higher levels of reactive oxygen species were restrained in plants under low levels of As. However, the levels of superoxide anion, hydrogen peroxide, and lipid peroxidation increased in response to the impaired antioxidant system induced by the highest As levels. Biomass decreased in plants exposed to As and scanning electron microscopy revealed root structural damage in the root cap of plants under 3.0 mg L−1 As. This work highlights that L. punctata can be considered a hyperaccumulator species and has potential for As phytoremediation when levels are lower than 1.0 mg L−1—a concentration 100-fold higher than that recommended for drinking water. Novelty Statement:Landoltia punctata can be considered a hyperaccumulator species and has the potential for arsenic phytoremediation when levels are lower than 1.0 mg L−1. [ABSTRACT FROM AUTHOR]

The presence of arsenic in potable water is a serious problem for human. Arsenic-containing water has irreparable effects on the consumer. So, the total objective of this work was to provide a photo-catalytic process to degrade of arsenic from aqueous solutions. The studied variables included H2O2 concentration, initial arsenic concentration, ZnO dosage, pH, and contact time. The intensity of the output light was equivalent to 600 mJ cm−2. The removal of arsenic efficiency by UV and H2O2 alone was 15% and 8%, respectively. In acidic conditions, the combined process had a higher removal efficiency for arsenic. pHzpc for ZnO was nearly 9. The optimal dose of ZnO nanoparticles was 1 g L−1. The average diameter of ZnO was from 52.27 to 304.8 nm. The optimal contact time was chosen for 45 min. After this time, the removal efficiency of arsenic has a slight difference. [ABSTRACT FROM AUTHOR]

Arsenic contamination in agricultural soil now imposing a major threat to crop productivity and causing several hazardous health effects through percolation in food chain. Bioremediation, an efficient way of soil health restoration toward sustainability offered by some soil-borne microorganisms, has been reported. The present work deals with application of two potent arsenic-tolerant bacterial strains (Bacillus thuringiensis A01 and Paenibacillus glucanolyticus B05), obtained from natural sources in modulating overall growth and antioxidant defense against arsenic-treated rice plants. Between the two, former could reduce arsenic uptake up to 56% (roots) and 85% (shoots), and the preceding one up to 31% (roots) and 65% (shoots) in a hydroponic environment. Germination percentage was noted to be enhanced significantly (p ≤ 0.05). Expression of oxidative stress defensive enzymes such as superoxide dismutase, peroxidase and catalase have been augmented at seedling stages (21 days) toward detoxification of arsenic imposed excess ROS generation. Increment of leaf Thiobarbituric acid reactive substances due to arsenic exposure have been ameliorated by both the bacterial application. Phenolic and flavonoid mediated free radical scavenging ability of the test plants elevated significantly (p ≤ 0.05). The present work revealed that, selected bacterial strains can perform efficient bioremediation against arsenic pollutant rice cultivation. [ABSTRACT FROM AUTHOR]

This article deals with the sensing properties of pristine phosphorene and those modified with boron, nitrogen, and arsenic toward sulfur trioxide (SO3) using density functional theory (DFT). The periodic calculations revealed a planar parallel configuration for the analyte. Among others, the arsenic-doped nanosensor showed the lowest adsorption energy (–3.04 kcal/mol) for the adsorbate at hand. The gas response correlated with the electrophilicity of the sensor at rest. Overall, the pristine phosphorene sensor provided the highest sensitivity (up to 64.9) and selectivity (16.9 with respect to nitrogen), followed by the arsenic-doped phosphorene layer, which was predicted to provide high sensitivity with respect to work function (13.4%) while exhibiting quick reusability (∼170 ns) at room temperature. The sensitivity to SO3 was dropped remarkably on a bilayer system in both cases, however. The results of this study would help design more efficient sensors of acidic gases. [ABSTRACT FROM AUTHOR]

The removal of As (V) from aqueous solution was investigated with the grafted polymeric adsorbent (chitosan-g-HEMA) synthesized by using high energy 60Co gamma radiation as well as by conventional chemical method. The swelling behavior of grafted polymer at different pH conditions and their kinetic studies were investigated. Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the grafted polymer and the morphological structure was analyzed by Scanning Electron Microscope (SEM). As (V) ions uptake capacity of the adsorbent was evaluated in the light of varying pH, contact time, temperature, adsorbent dose, and different arsenate ion concentration. The adsorption data was fitted well in the Langmuir model and various static parameters were calculated. The removal of toxic As (V) ions was carried out by batch method using grafted sorbents synthesized by both gamma radiation and chemical grafting methods and it was observed that the adsorbent synthesized by the use of gamma radiation shows higher adsorption capacity as compared to the chemically grafted polymer. [ABSTRACT FROM AUTHOR]

A sonochemical reduction method of permanganate (MnO4−) was utilized for preparation of manganese dioxide (MnO2) coating on the surface of XAD-4 resin. Characterization of the modified MnO2-coated XAD-4 resin (MX-4) was done and sorption studies were carried out using arsenic (76As) radiotracer. The adsorption capacity for As(III) and As(V) using MX-4 were 5.5 mg/g and 7.6 mg/g, respectively. The MX-4 resin was successfully applied for quantitative removal of arsenic from two ground water samples collected from arsenic contaminated regions of North 24 Parganas, West Bengal, India. A schematic mechanism of removal of arsenic by MX-4 beads was also suggested. [ABSTRACT FROM AUTHOR]

The sorption behavior of biochar derived from green seaweed (Ulva reticulata) toward arsenic(V) ions was explored in both batch and continuous modes. The pH edge experiments indicated optimum arsenic(V) sorption observed at pH 4, with maximum sorptional capacity of 7.67 mg/g through isotherm experiments. The kinetic experimental trials indicated that arsenic(V) sorption onto biochar was a fast electrostatic attraction process, with maximum removal occurred within 30 min. The sorption isotherms were modeled using the Toth, Redlich–Peterson, Langmuir and Freundlich isotherm models while the adsorption kinetics was modeled using the pseudo-first- and pseudo-second-order kinetic equations. The three-parameter models (Redlich–Peterson and Toth) better described the isotherm data, whereas pseudo-first-order model represented kinetic data well with low error and high correlation coefficient values. Among the different alkaline and acidic elutants investigated, the solution of 0.01 M NaOH effectively desorbed arsenic(V) from spent biochar. The feasibility of the biochar in continuous remediation of arsenic(V) from contaminated waters was explored in an up-flow fixed column. The biochar exhibited arsenic(V) removal efficiency and sorptional uptake of 59.5% and 8.12 mg/g, respectively. The biochar-loaded column was effectively desorbed using NaOH (0.01 M), with desorption efficiency of 99.5%. [ABSTRACT FROM AUTHOR]

A total of 200 rice and rice products from New Zealand and Australia were purchased from retail outlets during 2017 for inorganic arsenic analysis by ICP-MS. The survey of foods placed a particular emphasis on products marketed specifically for infants and young. A total of 159 samples (80%) gave positive results for inorganic arsenic, with a mean concentration of 0.06 mg/kg and a range of <0.01–0.14 mg/kg. Two products marketed for infants and young children age-cohort had the highest concentrations of inorganic arsenic. Both exceeded the EU maximum level for rice destined for the production of food for infants and young children of 0.1 mg/kg. The mean concentration of inorganic arsenic for only raw rice samples was 0.07 mg/kg, with a range of <0.02–0.12 mg/kg. In general, the concentration of inorganic arsenic in rice and rice products from New Zealand and Australia was low compared to concentrations reported from comparable studies overseas. [ABSTRACT FROM AUTHOR]

With the climate warming leading to thawing permafrost, the trace metal releasing from the permafrost is of increasing importance. The source area of the Yellow river (SAYR) in Tibet Plateau, underlain by permafrost which provides important source water, was investigated. One hundred and eleven water samples across SAYR were collected in April 2014, when permafrost thawing began and the precipitation season had not arrived yet. It was found that the arsenic concentration level was relatively higher than other pristine surface water in the world, but similar to other source regions on the Tibetan Plateau, showing SAYR is pristine and can serve as a reference region for determining the human influence on permafrost-affected landscapes. The positive correlation of arsenic with sulfate suggested that the arsenic was predominantly derived from the weathering process of arsenic-rich sulfides. Climate warming enhanced thawing depth of permafrost may accelerate the release and mobilization of arsenic to the surface water. [ABSTRACT FROM AUTHOR]

An adsorbent material arranged in a ceramic monolith (CM) obtained by extrusion technique using natural bentonite and alumina (as raw materials) is presented. Ceramic and raw materials were characterized by X-ray fluorescence, thermal analysis, X-ray diffraction, and textural analysis (with N2 adsorption–desorption at 77 K and Hg intrusion–extrusion porosimetry) to determine their chemical and physical properties. Then, As (V) adsorption capacity of the CM at different pH (3–9) using arsenic aqueous solution (with 2000 µg As (V) L−1) was evaluated. Additionally, studies of kinetics and equilibrium of As (V) adsorption on CM were performed. It was found that: (i) the As (V) removal capacity is favored at acidic pH, reaching an average value of 15 µg As (V) per gram of CM; (ii) from kinetic studies, As (V) adsorption on CM occur in two stages, the first of them reaching a lower As uptake in a short time period, followed by an slow second stage with a subsequent higher As uptake, which continued for a longer time period, reaching equilibrium conditions in approximately 24 h; and (iii) the As (V) adsorption isotherm is a type-Langmuir, indicating that the CM present an homo quantity of fixed sites to adsorb the As (V). [ABSTRACT FROM AUTHOR]

The present investigation was premeditated to explore the toxic effects of arsenic (As) on an essential oil-bearing plant, the menthol mint (Mentha arvensis L.). Arsenic was applied in the form of sodium arsenate (Na2HAsO4.7H2O) to the soil. Different concentrations of As (20, 40, 60, 80, and 100 mg kg-1of soil) were applied and one set of plants was kept as control. The response of plants towards As exposure was in a dose dependent order. Soil-applied As showed negative effects on the growth and physiological performance of plants. The chlorophyll, carotenoids content and chlorophyll fluorescence were significantly decreased by the As treatment ranging from 20 to 100 mg kg-1 of soil, however, maximum reduction was observed at the highest applied As concentration of 100 mg kg-1 of soil. The level of antioxidants whether enzymatic (superoxide dismutase, peroxidase) or non-enzymatic (proline) were enhanced by increasing the concentration of As to the plants with a slight decrease in activity of catalase (CAT) beyond 60 mg As kg-1of soil. The content of essential oil (EO) was significantly decreased at the highest concentration (100 mg As kg-1 of soil), but a slight increase in EO content was observed at 20 mg As kg-1 of soil. GC-MS analysis revealed the percentage of EO active components of the crop. The main constituent (menthol content) of the EO was also reduced at the maximum concentration of As. Interestingly; contents of menthyl acetate and menthone were enhanced in a dose dependent manner. Thus, the present study illustrates that the highest concentration of As proved toxic for mint crop. [ABSTRACT FROM AUTHOR]

Insects are promising sources of protein and lipid in feeds for farmed animals. In the European Union, the use of insect meal (IM) and insect oil is permitted in fish feed. However, the European Food Safety Authority has highlighted the lack of data regarding the chemical safety of insects and products thereof. In this study, Atlantic salmon (Salmo salar) were fed diets in which fish meal (FM) was partially or fully substituted with IM, resulting in four diets with an FM replacement of 0%, 33%, 66% and 100% by IM. The IM was produced from Black soldier fly (Hermetia illucens) larvae fed media containing 60% seaweed (Ascophyllum nodosum). After 16 weeks of feeding, fish fillet samples were collected. The concentrations of undesirable substances, e.g., heavy metals, arsenic, dioxins, mycotoxins, pesticides, in the IM, the diets and fillets were determined. The concentrations of the analysed compounds in the IM were all below EU maximum levels for feed ingredients, except for arsenic. However, for complete feeds the concentrations of these compounds in the feeds, including arsenic, were all below EU MLs. Arsenic was transferred from seaweed to IM, resulting in arsenic levels in IM similar to what has been documented for FM. Transfer of arsenic from feed to fillet was observed; however, total arsenic concentrations in the fillet significantly decreased when fish were fed diets with more IM and less FM. Arsenic speciation analysis of the diets showed that although total arsenic levels were similar, the arsenic species were different. Arsenobetaine was the major organoarsenic species in the diets containing FM, while in diets containing IM several unidentified arsenic species were detected. The results suggest that the lower feed-to-fillet transfer of arsenic when FM is replaced by IM may be due to the presence of arsenic species with low bioavailability in the IM. [ABSTRACT FROM AUTHOR]

This study investigated a potential method for the removal of arsenic from enargite leach solution containing 5.86 g/L As(V) by precipitation of magnesium ammonium arsenate (MAA). The experimental results showed the As(V) concentration can be reduced to 1.8 mg/L under the optimum conditions. The molar ratio NH4/Mg/As in precipitates formed at different pH values was checked by wet chemical analysis, indicating that some of by-products such as Mg3(AsO4)2, Mg(OH)2, and MgHAsO4 will be formed at the solution pH above or below pH 9.5. Notably, this study indicated MAA has a better ability for arsenic removal than magnesium arsenate. The precipitates also were characterized by XRD and SEM. [ABSTRACT FROM AUTHOR]

We herein report the development and testing of a novel material, namely activated carbon-supported nano titanium dioxide (ACTD) for the immobilization of arsenic in soil. This material, which was prepared using a sol-gel method, effectively reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiologically based extraction test (PBET) bioaccessibility of As(III) in soil samples. Upon processing the soils for 56 d at an ACTD dosage of 0.25 mmol g−1, the TCLP leachability of As(III) was reduced by 82.7–97.7%, while the bioaccessibility was lowered by 58.6–81.2%. In addition, sequential extraction resulted in an 11.5–96.0% decrease in the mobile-As(III) and the mobilizable-As(III) fractions, but an increase in the residual-As(III) fraction upon treatment with ACTD. These observations indicate that the application of ACTD could result in an 80% reduction in As(III) environmental leaching, thereby confirming that ACTD appears suitable for the treatment of arsenic-contaminated soil. [ABSTRACT FROM AUTHOR]

Manganese dioxide (MnO2) synthesized by solid-state reaction was characterized and sorption of As(III) and As(V) on it was studied in batch mode using 76As radiotracer. Arsenic removal efficiency was ∼98 % in the pH range of 3–9. Solvent extraction study indicated that >95% of arsenic is present as As(V) after sorption. A new electrochemical method was developed for explaining the arsenic–manganese interactions. Cyclic voltammetry and chronopotentiometry measurements were carried out which indicated the difference in the interaction of As(III) and As(V) with MnO2. X-ray Photoelectron Spectroscopy (XPS) was carried out in which the 3p3/2 binding energy peak of As(III) and As(V) standards was compared with the binding energy peaks observed for arsenic sorbed on manganese dioxide. The binding energy peaks of arsenic on MnO2 were matching with that of As(V), irrespective of the oxidation state of arsenic taken for sorption. The study confirmed that irrespective of the initial oxidation state, arsenic was sorbed on MnO2 as As(V); during the oxidation of As(III) by MnO2, manganese was reduced to Mn(II) and the Mn(II) formed during sorption was sorbed on the surface creating fresh surface promoting further sorption. Based on the observations, a mechanism of sorption has been proposed. [ABSTRACT FROM AUTHOR]

Carcinogenic effects of arsenic through consumption of contaminated water are an alarming threat and there is an emergent need to reduce extremely high levels of toxic arsenic from environment. Bacterial biofilms produce polyanionic extracellular polymeric substance (EPS) that is considered an excellent biosorbent material for the remediation of toxic metals and metalloids. This study was aimed to investigate the role of bacterial EPS in arsenic bioremediation. EPS was extracted from biofilm forming and arsenic reducer bacterial strains that were isolated from industrial waste water and characterized biochemically. Fourier transform infrared spectroscopy was also performed to study functional groups. Both Exiguobacterium profundum PT2 and Ochrobactrum ciceri SW1 exhibited enhanced EPS production in the presence of arsenic. Arsenic stress increased protein and carbohydrate contents in the EPS of both bacterial strains as indicated by the peaks of 1363 to 1613 and 1035 to 1218 cm−1 wavenumbers, respectively to cope with arsenic present in the surroundings. Shifting of peaks in As5+ treated samples from 1363 to 1379, 847 to 800 and 1211 to 1134 cm−1 demonstrated the involvement of proteins, carbohydrates and phosphates in the sequestration of arsenic. Scanning electron microscopic examination of EPS revealed structural alterations such as the presence of closely embedded large clumps with interstitial spaces between stacked layers of the EPS of E. profundum PT2 treated with As5+ displayed the enhanced polysaccharide content and arsenic sorption. Therefore, increased production of bacterial EPS with large number of polyanionic functional groups on its surface having tendency to sequester arsenic through electrostatic or covalent interactions presented EPS an excellent biosorbent material for arsenic bioremediation. [ABSTRACT FROM AUTHOR]

Background:Arsenic trioxide (ATO) is widely applied to treat acute promyelocytic leukemia (APL). To elucidate metabolism and toxicity of arsenic, we analyzed time course of arsenic species in red blood cells (RBCs) of APL patients. Methods:Nine APL patients received ATO (0.16 mg/kg/day) through 18-h infusion. Blood was collected before daily administration (days 2 to 9), and at different time points on day 8. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were detected by HPLC-ICP-MS. Results:Arsenic species reached Cmax at 18 h on day 8. Arsenicals gradually accumulated during days 2 to 9, whereas their percentages remained almost constant. The general trend in red blood cells (RBCs) was iAs > MMA > DMA. MMA was consistently the predominant methylated arsenic metabolite in RBCs. iAs, MMA, and tAs (tAs = iAs + DMA + MMA) concentrations (P < 0.0001), MMA/DMA ratios (P = 0.0016) and iAs% (P = 0.0013) were higher in RBCs than in plasma. Conclusions:Time course of arsenic species reveal kinetic characteristic of ATO metabolites in RBCs. Arsenic species accumulated with administration frequency. Arsenic species in RBCs were remarkably different from those in plasma. Time course of arsenic species in RBCs is important in ATO clinical application. [ABSTRACT FROM AUTHOR]

High energy 60Co gamma radiation was used for degradation of chitosan under different radiation doses. Molecular weight of degraded chitosan was determined by intrinsic viscosity measurement. The intrinsic viscosity values were used to determine the viscosity-average molecular weight of degraded oligo-chitosan using Mark-Houwink equation. Degraded chitosan was investigated for its suitability as an adsorbent for removal of As (V) from aqueous solution. The adsorption capacity of degraded chitosan on As (V) was compared with pristine chitosan. The process of adsorption of As (V) ions was monitored and various adsorption parameters were evaluated. The experimental results indicate that adsorption of As (V) decreases with increasing rate of degradation of chitosan. [ABSTRACT FROM AUTHOR]

Among the heavy metals and other chemicals that contaminate the immediate environment of all gold mining communities, Arsenic and Mercury compounds are some of the most prevalent, exposing residents to their health risks. This menace is the result of the mining activities, particularly, Artisanal and Small-scale gold mining, in these communities. Among the mining areas in Ghana, Artisanal and small-scale gold mining is a recent activity only in the Eastern Region, particularly in the Aduasena, Afosu, Intronang, Hweakwae, New Abirem, Mamano and Hamlets communities. The objective of this research is to investigate the levels of Arsenic and Mercury in the residents of these seven communities using spectroscopic analysis of their urine samples and to identify which gender and at what age does any resident in a typical Ghanaian mining community stand most endangered by the levels of these contaminants. Samples of first urine void of residents upon waking up in the morning were taken, digested with nitric acid and analysed for the concentrations of Arsenic and Mercury using the Perkin Elmer PinAAcle 900T Graphite Furnace AAS. The spectroscopic analysis of the urine samples showed that more than 20% of the residents had concentrations of Arsenic higher than the (normal) recommended level, with some reaching as high as 221 μ g / L for Arsenic and 3.90 μ g / L for mercury. Statistical analysis of the results showed that the levels of both Arsenic and Mercury seem to increase with increasing age, despite some extremely high concentrations for arsenic in the Aduasena youth between 31 and 40 years. This trend indicates that males were seen to be more at risk from these contaminants, with the youth between 11 and 20 years standing most endangered. [ABSTRACT FROM AUTHOR]

Several low-molecular-weight organic carbon (LMWOC) compounds (acetate, propionate, butyrate, lactate, and glucose) were added to flooded arsenic-rich tailing mine soil to investigate their effect to the mobilization of As/Fe and potential shift of microbial community. A promoting effect to the mobilization and biotransformation of As(V)/Fe(III) in the soils resulting from the supplementation with LMWOCs substrate was indicated compared to the biotic microcosm amended with deionized water alone. During 38-day biotic incubation, more than 2100 μg/L of As(III) and 4.2 mg/L of Fe(II) levels were released from the soils amended with LMWOCs substrates, compared to the levels of As(III) and Fe(II) (less 35 μg/L and 1.82 mg/L) derived from the biotic supplementation with deionized water alone. PCR-DGGE indicated that several LMWOCs-responded bacteria were mostly related to Firmicutes and Proteobacteria. Moreover, a negligible impact on the abundance of Fe(III)-reducing family Geobacteraceae was indicated in the LMWOCs-amended soils. However, an increased abundance of sulfate-reducing bacteria but a decreased abundance of arsenate-respiring bacteria were indicated upon the soils supplemented with acetate alone, compared with other LMWOC amendments. DNA-stable isotope probing analysis demonstrated that the dual roles of acetate was not only served as an electron donor for biotransformation of As(V)/Fe(III) in soil, but also assimilated as a powerful energy source to promote the growth of sulfate-reducing bacteria. The findings suggest that there are specific bacteria that preferentially respond to the additions of LMWOC for controlling the biochemical cycle process of As/Fe in soils. [ABSTRACT FROM AUTHOR]

Inorganic arsenic (iAs) is a contaminant present in food, especially in rice and rice-based products. Toxicity of arsenic compounds (As) depends on species and oxidative state. iAs species, such as arsenite (As(III)) and arsenate (As(V)), are more bioactive and toxic than organic arsenic species, like methylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) or arsenosugars and arsenobetaine. An ion chromatography-inductively coupled-plasma-mass spectroscopy method was developed to separate the four following arsenic anions: As(III), As(V), MMA(V) and DMA(V). Sample preparation was done in mild acidic conditions to ensure species preservation. The predominant arsenic species found in rice and rice-based products, except for rice drinks, was As(III), with 60-80% of the total As content, followed by DMA(V) and As(V). MMA(V) was measured only at low levels (<3%). Analyses of rice products (N = 105) intended for toddlers, including special products destined for infants and toddlers, such as dry form baby foods (N = 12) or ready-to-use form (N = 9), were done. It was found in this study that there is little or no margin of exposure. Risk assessment, using the occurrence data and indicated intake scenarios compared to reference BMDLs as established by EFSA, demonstrated toddlers with a high consumption of rice based cereals and rice drinks are at risk of high iAs exposure, for which a potential health risk cannot be excluded. [ABSTRACT FROM AUTHOR]

Sodium arsenite (NaAsO2) is one of the major environmental toxicants with severe toxicological consequences in some developing and developed countries. Rats in Group A received normal saline. Genotoxicity and apoptosis were induced by single intraperitoneal injection of 10 mg/kg sodium arsenite to rats in Groups B–F. Rats in Groups C and D had earlier been pretreated with Azadirachta indica (100 and 200 mg/kg) or E and F with vitamin E (50 and 100 mg/kg), respectively. Markers of oxidative stress, inflammation, hepatic damage, genotoxicity, and apoptosis were assessed. Pretreatment of rats with either Azadirachta indica or vitamin E led to a significant (p <.05) increase in the activities of glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) in the liver compared to the group that received NaAsO2 alone. Markers of oxidative stress and inflammation, malondialdehyde (MDA), hydrogen peroxide (H2O2) generation, nitric oxide (NO), and myeloperoxidase (MPO), were significantly (p <.05) lowered in rats pretreated with Azadirachta indica or vitamin E. The frequency of micronucleated polychromatic erythrocytes (MNPCEs) and expression of caspase-3 were significantly (p <.05) reduced in rats pretreated with either Azadirachta indica or vitamin E compared to rats intoxicated with arsenite. Histopathology of the liver showed areas of infiltration of inflammatory cells with deaths of numerous hepatocytes in NaAsO2-intoxicated rats, and these were reversed by Azadirachta indica. Together, we report for the first time the genoprotective and antiapoptotic effect of Azadirachta indica by a significant reduction in the frequency of micronuclei-induced apoptosis and oxidative stress by arsenic intoxication. [ABSTRACT FROM AUTHOR]

Arsenic trioxide (As2O3) is a promising new regimen for the treatment of acute promyelocytic leukemia (APL). The induction of oxidative stress mediated by reactive oxygen species (ROS) and excessive intracellular calcium influx are the main reasons behind (As2O3) toxicity. Since liver is the major organ for xenobiotic metabolism, it is always under stress. Antioxidant vitamins such as LAscorbic acid (L-AA) and a-Tocopherol (α-TOC) have been proposed to have beneficial effects against a variety of pathological conditions and are known by their free radical scavenging properties. The present study evaluates the curative efficacy of L-AA and a-TOC against As2O3 toxicity using immortalized human Chang liver cells. Our results suggest that L-AA (100 mM) and α-TOC (50 mM) recovered (As2O3) (10 mM) cytotoxicity. Furthermore, (As2O3) treatment showed an increase in lipid peroxidation and depletion in antioxidant status, mitochondrial trans membrane potential and values of total antioxidant capacity. Cotreatment of antioxidant vitamins with (As2O3) resulted in a significant reversal of oxidative stress markers. Our findings substantiate the effect of antioxidant vitamins in protecting the hepatocytes from oxidative stress which may be attributed through Nrf2 (Nuclear factor erythroid 2-related factor 2) mediated upregulation of Bcl2 (B-cell lymphoma 2) expression. [ABSTRACT FROM AUTHOR]

The granular activated carbon/MnFe2O4composite with a mass ratio of 2:1 was synthesized using a simple chemical coprecipitation procedure and used for the removal of As(III) and As(V) from synthetically prepared wastewater. Physicochemical analysis of the composite was carried out through Brunauer, Emmett and Teller surface area and total pore volume, Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Micrograph and Energy-Dispersive X-Ray Spectroscopy (SEM-EDX). The impact of various adsorption parameters such as the initial pH, adsorbent dose, contact time, temperature and initial arsenic concentration were systematically investigated to evaluate the optimum operating conditions. Nonlinear regression analysis was employed to identify the best-fit isotherm on the basis of three correlation coefficients and three error functions and also to predict the parameters involved in one one-parameter, six two-parameter, nineteen three-parameter, three four-parameter and one five-parameter isotherms. The maximum adsorption capacities estimated using the Langmuir model were 1253 mg/g for As(III) and 1314 mg/g for As(V) at 30 °C temperature and 70 min contact time. The results showed that As(III) and As(V) removal was strongly pH-dependent with an optimum pH value of 7.0 and 4.0, respectively. The mean adsorption energy (E) calculated from the D–R model indicated the nature of adsorption being ion exchange type. [ABSTRACT FROM AUTHOR]

The association of arsenic variables in urine, total arsenic (UAS), arsenobetaine (UAB), dimethylarsinic acid (UDMA), and arsenic adjusted for arsenobetaine (UAAS) with thyroid-stimulating hormone (TSH), free and total serum thyroxine (FT4, TT4), free and total triiodothyronine (FT3, TT3), and thyroglobulin (TGN) was evaluated by analyzing data from 2007–2010 National Health and Nutrition Examination Survey. For iodine deficient males, there was a positive association between TSH and UDMA (p < 0.01) and a negative association between the levels of TT4 and UDMA (p < 0.01). Levels of UAAS were inversely associated with the levels of TT4 for both iodine-deficient (p = 0.054) and iodine-replete females (p < 0.01). For iodine-replete females, levels of both TSH and TGN increased with decrease in the levels of both UAB (p < 0.01) and UAS (p < 0.01). There was also a negative association between TSH and UAB as well as UAS (p < 0.01). For iodine-replete males, increased levels of UDMA were associated with decreasing levels of FT4 (p = 0.03). [ABSTRACT FROM AUTHOR]

Three compounds, [AsMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·4H2O (1), [PMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·3H2O (2) and [PMo8V6O42][Cu(2,2ʹ-bpy)2]2[Cu(2,2ʹ-bpy)]·3.5H2O (3), have been synthesized under hydrothermal conditions and characterized by IR, UV–vis, XRD, TG, elemental analysis, and X-ray diffraction analysis. Single-crystal X-ray structure analysis reveals that1and2are isostructural and isomorphous, whereas2and3are polymorphs. Polymorphs of1have not been synthesized yet. The mixed-valent transition metal ion in1–3has been further confirmed by TG analyses. Catalytic properties of1and2have also been studied. [ABSTRACT FROM PUBLISHER]

1. Arsenite alters the expression of aryl hydrocarbon receptor (AhR)-regulated genes in extrahepatic tissues; yet, the effect of organic arsenicals still unknown. Therefore, C57BL/6 mice received trimethylarsine oxide (TMAO; 13 mg/kg i.p.) with or without 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 15 μg/kg), and euthanized at 6 or 24 h. 2. Our results demonstrated that TMAO increased Cyp1a1 and Cyp1b1 mRNA, protein and activity in the lung. TMAO potentiated the TCDD-mediated induction of Cyp1a1 and Cyp1a2 mRNA, protein and activity in the lung. In the kidney, TMAO increased Cyp1b1 mRNA and protein. TMAO potentiated the TCDD-mediated induction of Cyp1a1 and Cyp1b1 mRNA, protein and activity. In the heart, TMAO potentiated the TCDD-mediated induction of Cyp1a1 and Cyp1b1 mRNA. 3. Moreover, TMAO induced Nqo1 mRNA in the lung, kidney and heart, with subsequent increase in Nqo1 protein and activity in the lung. TMAO increased Gsta mRNA in the heart; and increased Gsta protein and activity in the lung and kidney. TMAO increased Nqo1 mRNA as compared to TCDD in the kidney and heart, and potentiated the TCDD-mediated induction of Gsta protein and activity in the kidney. 4. In conclusion, TMAO modulates AhR-regulated genes in a tissue- and enzyme-specific manner. [ABSTRACT FROM AUTHOR]

Arsenite (AsO33-) is the dominant arsenic (As) oxyanion in most of As rich groundwaters, generating serious health problems worldwide. It is assumable that the isotopic composition of the associated oxygen may broaden our understanding about the causes, which led to the appearance of this kind of contamination. The aim of this study was to work out an efficient method for the selective extraction of arsenite from natural water samples, in a form adequate for isotopic measurements. Three adsorbents, i. basic yttrium carbonate (BYC), ii. porous polymer beads loaded with monoclinic hydrous zirconium oxide (MHZR), and iii. nanoparticlate Fe2O3(NFO) were tested for their suitability to separating AsO33-from coexisting anions that may interfere with the isotopic measurement. Results show that 95.1%, 99.3%, and 98.2% of AsO33-were adsorbed selectively and separated from SO42-and Cl-in water by BYC, MHZR, and NFO, respectively. Using different desorption agents, 95.0% and 87.5% of AsO33-were stripped from BYC in 0.05 M HNO3and NFO in 2 M NaOH, respectively, but only 27.5% from MHZR. By adding AgNO3in excess to these solutions, 98.3 ± 1.28% (n = 4) and 95.7 ± 4.81% (n = 4) of the AsO33-, desorbed from the BYC and NFO, were precipitated as Ag3AsO3, respectively. The purity of the precipitates was checked with SEM-EDX. [ABSTRACT FROM AUTHOR]