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Arsenic
Kinds of Arsenic Terms modified by Arsenic Selected AbstractsARSENIC IN THE SHALLOW GROUND WATERS OF CONTERMINOUS UNITED STATES: ASSESSMENT, HEALTH RISKS, AND COSTS FOR MCL COMPLIANCE,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2006Navin Kumar C. Twarakavi ABSTRACT: A methodology consisting of ordinal logistic regression (OLR) is used to predict the probability of occurrence of arsenic concentrations in different threshold limits in shallow ground waters of the conterminous United States (CONUS) subject to a set of influencing variables. The analysis considered a number of maximum contaminant level (MCL) options as threshold values to estimate the probabilities of occurrence of arsenic in ranges defined by a given MCL of 3, 5, 10, 20, and 50 ,g/l and a detection limit of 1 ,g/l. The fit between the observed and predicted probability of occurrence was around 83 percent for all MCL options. The estimated probabilities were used to estimate the median background concentration of arsenic in the CONUS. The shallow ground water of the western United States is more vulnerable than the eastern United States. Arizona, Utah, Nevada, and California in particular are hotspots for arsenic contamination. The risk assessment showed that counties in southern California, Arizona, Florida, and Washington and a few others scattered throughout the CONUS face a high risk from arsenic exposure through untreated ground water consumption. A simple cost effectiveness analysis was performed to understand the household costs for MCL compliance in using arsenic contaminated ground water. The results showed that the current MCL of 10 ,g/l is a good compromise based on existing treatment technologies. [source] Electrochemical Detection of Arsenic(III) in the Presence of Dissolved Organic Matter (DOM) by Adsorptive Square-Wave Cathodic Stripping Voltammetry (Ad-SWCSV)ELECTROANALYSIS, Issue 4 2008Tsanangurayi Tongesayi Abstract This study has demonstrated that As(III) can be electrochemically detected and quantified in the presence of fulvic acid (FA) and dissolved organic matter (DOM). This eliminates the need to remove DOM prior to measurement of As(III) in environmental samples. Apart from reducing analysis time and the cost of the analysis, this could be potentially useful for the development of electrochemical methods for the detection and measurement of As(III) onsite. Both synthetic samples in which FA was added and a real sample with 22.16,mg/L total organic carbon (TOC) were analyzed. [source] Heavy Metals in Matrices of Food Interest: Sequential Voltammetric Determination at Trace and Ultratrace Level of Copper, Lead, Cadmium, Zinc, Arsenic, Selenium, Manganese and Iron in MealsELECTROANALYSIS, Issue 18 2004Clinio Locatelli Abstract The voltammetric methods are very suitable and versatile techniques for the simultaneous metal determination in complex matrices. The present work, regarding the sequential determination of Cu(II), Pb(II), Cd(II), Zn(II) by square-wave anodic stripping voltammetry (SWASV), As(III), Se(IV) by square-wave cathodic stripping voltammetry (SWCSV) and Mn(II), Fe(III) by square-wave voltammetry (SWV) in matrices involved in foods and food chain as wholemeal, wheat and maize meal, are an interesting example of the possibility to sequentially determine each single element in real samples. Besides the set up of the analytical method, particular attention is aimed either at the problem of possible signal interference or to show that, using the peak area Ap as instrumental datum, it is possible to achieve lower limits of detection. The analytical procedure was verified by the analysis of the standard reference materials: Wholemeal BCR-CRM 189, Wheat Flour NIST-SRM 1567a and Rice Flour NIST-SRM 1568a. Precision, as repeatability, and accuracy, expressed as relative standard deviation and relative error, respectively, were lower than 6% in all cases. In the presence of reciprocal interference, the standard addition method considerably improved the resolution of the voltammetric technique. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial meals sampled on market for sale. A critical comparison with spectroscopic measurements is also discussed. [source] Analysis and Speciation of Traces of Arsenic in Environmental, Food and Industrial Samples by Voltammetry: a ReviewELECTROANALYSIS, Issue 9 2004Andrea Cavicchioli Abstract Voltammetric approaches for the determination of arsenic and speciation at trace levels are critically appraised in a review covering the literature from 1970 to 2002. Special attention is devoted to stripping modes and to issues related to the choice of working material and supporting electrolyte. A section is dedicated to the management of real samples and aspects of sample preparation. An extensive compilation, organized by real sample type, gathers essential experimental conditions. Potentiometric stripping analysis is introduced for sake of comparison. The coupling of voltammetric detection or preaccumulation with FIA, chromatography, capillary electrophoresis and ICP techniques is also addressed. [source] Speciation of Arsenic under Dynamic ConditionsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2008J. Ackermann Abstract In periodically flooded soils, reductive conditions can occur, which favor the dissolution of Fe (hydr)oxides. Fe (hydr)oxides such as goethite are important sorbents for arsenate (AsV), which is the dominant As species in soils under aerobic conditions. Hence, the dissolution of Fe (hydr)oxides under reductive conditions can result in the mobilization and reduction of AsV and, thus, in an increase in the bioavailability of arsenic. The temporal dynamics of these processes and possible re-sorption or precipitation of arsenite (AsIII) formed are poorly understood. Under controlled laboratory conditions, the temporal change in the redox potential and arsenic speciation with time after a simulated flooding event in a quartz-goethite organic matter substrate, spiked with AsV, was examined. During a period of 6,weeks, substrate solutions were sampled weekly using micro-suction cups and analyzed for pH, AsIII and AsV, Fe, Mn and P concentrations. Redox potentials and matric potentials were determined in situ in the substrate-bearing cylinders. The redox potential and the ratio between AsIII and AsV concentrations remained unchanged during the experiment without organic matter application. With organic matter applied, the redox potential decreased and the AsIII concentrations in the substrate solution increased while the total As concentrations in the substrate solution strongly decreased. An addition of goethite (1,g/kg) per se led to a decrease of the total As in the substrate solution (almost 50,%). In respect to the potential As availability for plants, and consequently, the transfer into the food chain, the results are difficult to evaluate. The lower the total As concentrations in the substrate solution, determined with decreasing redox potential, the least plant As uptake will occur. This effect may however be compensated by a shift of the molar P/AsV ratio in the solution in favor of AsV which is expected to increase the As uptake. [source] Optimization of an Iron Intercalated Montmorillonite Preparation for the Removal of Arsenic at Low Concentrations,ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2007D. Masih Abstract A series of iron intercalated montmorillonites (Fe-Monts) were prepared using (i) ion exchange of native sodium and calcium ions with iron ions, (ii) base hydrolysis of inserted iron ions in montmorillonite suspension, and (iii) insertion of pre-hydrolyzed iron colloid in montmorillonite. The materials were characterized by X-ray diffraction and gas adsorption-desorption techniques. The basal d(001)-spacing and BET specific surface area increased after the intercalation of iron species in montmorillonite. Local iron structure studied by X-ray absorption fine structure (XAFS) spectroscopy showed an unsaturation of the Fe···Fe coordination number (N 2.5) of the intercalated iron species as compared to the bulk iron oxyhydroxides (N 6). The Fe-Monts were employed for arsenic removal from aqueous solutions at low concentration (0.2,16 mg/L). Among the Fe-Monts, the one prepared by the hydrolysis of inserted iron ions, was the best in performance. The saturation adsorption amount of the optimized iron-montmorillonite was 4 and 28 times higher for the removal of arsenite and arsenate, respectively, as compared to bulk iron oxyhydroxide (goethite). Compared with bulk iron oxyhydroxide, the Fe-Monts were superior for arsenate uptake and comparable for arsenite. In addition, arsenite adsorbed on the Fe-Monts was found to be oxidized to arsenate based on XAFS spectroscopy. [source] Arsenate and dimethylarsinic acid in drinking water did not affect DNA damage repair in urinary bladder transitional cells or micronuclei in bone marrow,ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2009Amy Wang Abstract Arsenic is a human skin, lung, and urinary bladder carcinogen, and may act as a cocarcinogen in the skin and urinary bladder. Possible modes of action of arsenic carcinogenesis/cocarcinogenesis include oxidative stress induction and inhibition of DNA damage repair. We investigated the effects of arsenic in drinking water on DNA damage repair in urinary bladder transitional cells and on micronucleus formation in bone marrow. F344 rats were given 100 ppm arsenate [As(V)] or dimethylarsinic acid [DMA(V)] in drinking water for 1 week. The in vivo repair of cyclophosphamide (CP)-induced DNA damage resulting from a single oral gavage of CP, and the in vitro repair of hydrogen peroxide (H2O2)- or formaldehyde-induced DNA damage, resulting from adding H2O2 or formaldehyde into cell medium, were measured by the Comet assay. DMA(V) effects were not observed on either CP-induced DNA damage induction or on DNA repair. Neither DMA(V) nor As(V) increased the H2O2 - or formaldehyde-induced DNA damage, and neither inhibited the repair of H2O2 -induced DNA damage. Neither DMA(V) nor As(V) increased the micronucleus frequency, nor did they elevate micronucleus frequency resulting from CP treatment above the level observed by the treatment with CP alone. These results suggest that arsenic carcinogenesis/cocarcinogenesis in the urinary bladder may not be via DNA damage repair inhibition. To our knowledge this is the first report of arsenic effects on DNA damage repair in the urinary bladder. Environ. Mol. Mutagen. 2009. Published 2009 by Wiley-Liss, Inc. [source] Arsenic, lead, and other trace elements in soils contaminated with pesticide residues at the Hanford site (USA)ENVIRONMENTAL TOXICOLOGY, Issue 2 2003Jerry Yokel Abstract The primary purpose of this study was to characterize arsenic (As) and lead (Pb) concentrations in former orchard soils contaminated with lead arsenate pesticides at the Hanford site in Washington state (USA). Surface samples (n = 31) were collected from former orchard soils (in cultivation during the pre-Hanford period) at five locations at the 100 Areas and at one location at the Old Hanford Townsite (OHT). Another set of samples (n = 17) was collected over a soil depth interval of 10,50 cm at the four locations with the highest As and Pb surface concentrations. All samples were analyzed for 22 trace elements (including As and Pb) with inductively coupled plasma,atomic emission spectrometry (ICP,AES). The mean, standard deviation, and range for As in the surface soils were 30, 61, and 2.9,270 mg/kg dry wt, respectively. The corresponding statistics for Pb were 220, 460, and 6.5,1900 mg/kg dry wt, respectively. As and Pb concentrations in the surface soils were positively and significantly correlated (r = 0.91, Bonferroni p < 0.05). Descriptive statistics and bivariate correlations were also computed for other trace elements. As and Pb mean concentrations in the surface soils each differed significantly (p < 0.05) among Hanford locations, with the highest concentrations at the 100-H and 100-F Areas. Although both As and Pb mean concentrations decreased with soil depth, regression and correlation coefficients only, for Pb significantly differed from zero (b = ,0.0372, r = ,0.805, Bonferroni p < 0.05). Compared with data in the literature As and Pb concentrations found in this study exceeded background levels but were typical of orchard soils. Furthermore, mean As and Pb soil concentrations were in the range of various toxicological benchmarks derived for protection of human and ecological receptors. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 104,114, 2003 [source] Arsenic induces caspase- and mitochondria-mediated apoptosis in Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 6 2007Li Du Abstract In recent years, it has been shown that yeast, a unicellular organism, undergoes apoptosis in response to various factors. Here we demonstrate that the highly effective anticancer agent arsenic induces apoptotic process in yeast cells. Reactive oxygen species (ROS) production was observed in the process. Moreover, mitochondrial membrane potential decreased after arsenic treatment. Resistance of the rho0 mutant strain (lacking mtDNA) to arsenic provides further evidence that this death process involves mitochondria. In addition, hypersensitivity of ,sod1 to arsenic suggests the critical role of ROS. Cell death and DNA fragmentation decreased in a ,yca1 deletion mutant, indicating the participation of yeast caspase-1 protein in apoptosis. The implications of these findings for arsenic-induced apoptosis are discussed. [source] Glacial Sediment Causing Regional-Scale Elevated Arsenic in Drinking WaterGROUND WATER, Issue 6 2005Melinda L. Erickson In the upper Midwest, USA, elevated arsenic concentrations in public drinking water systems are associated with the lateral extent of northwest provenance late Wisconsin-aged drift. Twelve percent of public water systems located within the footprint of this drift (212 of 1764) exceed 10 ,g/L arsenic, which is the U.S. EPA's drinking water standard. Outside of the footprint, only 2.4% of public water systems (52 of 2182) exceed 10 ,g/L arsenic. Both glacial drift aquifers and shallow bedrock aquifers overlain by northwest provenance late Wisconsin-aged sediment are affected by arsenic contamination. Evidence suggests that the distinct physical characteristics of northwest provenance late Wisconsin-aged drift,its fine-grained matrix and entrained organic carbon that fosters biological activity,cause the geochemical conditions necessary to mobilize arsenic via reductive mechanisms such as reductive desorption and reductive dissolution of metal oxides. This study highlights an important and often unrecognized phenomenon: high-arsenic sediment is not necessary to cause arsenic-impacted ground water,when "impacted" is now defined as >10 ,g/L. This analysis also demonstrates the scientific and economic value of using existing large but imperfect statewide data sets to observe and characterize regional-scale environmental problems. [source] Arsenic in Glacial Aquifers: Sources and Geochemical ControlsGROUND WATER, Issue 4 2005Walton R. Kelly A total of 176 wells in sand-and-gravel glacial aquifers in central Illinois were sampled for arsenic (As) and other chemical parameters. The results were combined with archived and published data from several hundred well samples to determine potential sources of As and the potential geochemical controls on its solubility and mobility. There was considerable spatial variability in the As concentrations. High concentrations were confined to areas smaller than 1 km in diameter. Arsenic and well depth were uncorrelated. Arsenic solubility appeared to be controlled by oxidation-reduction (redox) conditions, especially the presence of organic matter. Geochemical conditions in the aquifers are typically reducing, but only in the most reducing water does As accumulate in solution. In wells in which total organic carbon (TOC) was below 2 mg/L and sulfate (SO42,) was present, As concentrations were low or below the detection limit (0.5 ,g/L). Arsenic concentrations >10 ,g/L were almost always found in wells where TOC was >2 mg/L and SO42, was absent or at low concentrations, indicating post,SO42,reducing conditions. Iron (Fe) is common in the aquifer sediments, and Fe oxide reduction appears to be occurring throughout the aquifers. Arsenic is likely released from the solid phase as Fe oxide is reduced. [source] Arsenic in Glacial Drift Aquifers and the Implication for Drinking Water,Lower Illinois River BasinGROUND WATER, Issue 3 2001Kelly L. Warner The lower Illinois River Basin (LIRB) covers 47,000 km2 of central and western Illinois. In the LIRB, 90% of the ground water supplies are from the deep and shallow glacial drift aquifers. The deep glacial drift aquifer (DGDA) is below 152 m altitude, a sand and gravel deposit that fills the Mahomet Buried Bedrock Valley, and overlain by more than 30.5 m of clayey till. The LIRB is part of the USGS National Water Quality Assessment program, which has an objective to describe the status and trends of surface and ground water quality. In the DGDA, 55% of the wells used for public drinking-water supply and 43% of the wells used for domestic drinking water supply have arsenic concentrations above 10 ,g/L (a new U.S. EPA drinking water standard). Arsenic concentrations greater than 25 ,g/L in ground water are mostly in the form of arsenite (AsIII). The proportion of arsenate (AsV) to arsenite does not change along the flowpath of the DGDA. Because of the limited number of arsenic species analyses, no clear relations between species and other trace elements, major ions, or physical parameters could be established. Arsenic and barium concentrations increase from east to west in the DGDA and are positively correlated. Chloride and arsenic are positively correlated and provide evidence that arsenic may be derived locally from underlying bedrock. Solid phase geochemical analysis of the till, sand and gravel, and bedrock show the highest presence of arsenic in the underlying organic-rich carbonate bedrock. The black shale or coal within the organic-rich carbonate bedrock is a potential source of arsenic. Most high arsenic concentrations found in the DGDA are west and downgradient of the bedrock structural features. Geologic structures in the bedrock are potential pathways for recharge to the DGDA from surrounding bedrock. [source] Effect of Well Disinfection on Arsenic in Ground WaterGROUND WATER MONITORING & REMEDIATION, Issue 2 2008Madeline Gotkowitz Domestic water wells are routinely subjected to in situ chemical disinfection treatments to control nuisance or pathogenic bacteria. Most treatments are chlorine based and presumably cause strongly oxidizing conditions in the wellbore. Water resource managers in Wisconsin were concerned that such treatments might facilitate release of arsenic from sulfide minerals disseminated within a confined sandstone aquifer. To test this hypothesis, a well was subjected to four disinfection treatments over 9 months time. The first treatment consisted of routine pumping of the well without chemical disinfection; three subsequent treatments included chlorine disinfection and pumping. Pretreatment arsenic concentrations in well water ranged from 7.4 to 18 ,g/L. Elevated arsenic concentrations up to 57 ,g/L in the chemical treatment solutions purged from the well are attributed to the disintegration or dissolution of biofilms or scale. Following each of the four treatments, arsenic concentrations decreased to less than 10 ,g/L during a period of pumping. Arsenic concentrations generally returned to pretreatment levels under stagnant, nonpumping conditions imposed following each treatment. Populations of iron-oxidizing, heterotrophic, and sulfate-reducing bacteria decreased following chemical treatments but were never fully eradicated from the well. Strongly oxidizing conditions were induced by the chlorine-based disinfections, but the treatments did not result in sustained increases in well water arsenic. Results suggest that disruption of biofilm and mineral deposits in the well and the water distribution system in tandem with chlorine disinfection can improve water quality in this setting. [source] Regulation of Arsenic in Drinking Water Affects Ground Water SystemsGROUND WATER MONITORING & REMEDIATION, Issue 1 2002Charles Job First page of article [source] Impact of Regional Geology on Water Arsenic in Ground Water Studied: Mercury Pollution from Dentistry AlleviatedGROUND WATER MONITORING & REMEDIATION, Issue 2 2000Article first published online: 22 FEB 200 No abstract is available for this article. [source] Protective effect of arjunolic acid against arsenic-induced oxidative stress in mouse brain,JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 1 2008Mahua Sinha Abstract Arsenic, a notoriously poisonous metalloid, is ubiquitous in the environment, and it affects nearly all organ systems of animals including humans. The present study was designed to investigate the preventive role of a triterpenoid saponin, arjunolic acid against arsenic-induced oxidative damage in murine brain. Sodium arsenite was selected as a source of arsenic for this study. The free-radical-scavenging activity and the in vivo antioxidant power of arjunolic acid were determined from its 2,2-diphenyl-1-picryl hydrazyl radical scavenging ability and ferric reducing/antioxidant power assay, respectively. Oral administration of sodium arsenite at a dose of 10 mg/kg body weight for 2 days significantly decreased the activities of antioxidant enzymes, superoxide dismutase, catalase, glutathione- S -transferase, glutathione reductase and glutathione peroxidase, the level of cellular metabolites, reduced glutathione, total thiols and increased the level of oxidized glutathione. In addition, it enhanced the levels of lipid peroxidation end products and protein carbonyl content. Treatment with arjunolic acid at a dose of 20 mg/kg body weight for 4 days prior to arsenic administration almost normalized above indices. Histological findings due to arsenic intoxication and arjunolic acid treatment supported the other biochemical changes in murine brains. Results of 2,2-diphenyl-1-picryl hydrazyl radical scavenging and ferric reducing/antioxidant power assays clearly showed the in vitro radical scavenging as well as the in vivo antioxidant power of arjunolic acid, respectively. The effect of a well-established antioxidant, vitamin C, has been included in the study as a positive control. Combining all, results suggest that arjunolic acid possessed the ability to ameliorate arsenic-induced oxidative insult in murine brain and is probably due to its antioxidant activity. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:15,26, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20209 [source] Defective ,1 -integrins expression in arsenical keratosis and arsenic-treated cultured human keratinocytesJOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2006Chih-Hung Lee Background:, ,1 -integrins, which localize to the basolateral surface of basal keratinocytes, are important in the differentiation control and proliferation of the epidermis. Many cutaneous diseases with perturbed differentiation, including arsenical keratosis, show altered patterns of integrin distribution and expression. Arsenic may induce arsenical keratosis through the differentiation and apoptosis aberration by integrins. The purpose of this study is to investigate the role of integrin and arsenic in the pathogenesis of arsenical keratosis. Methods:, Twenty-five specimens obtained from 25 patients with arsenical keratosis disease were studied. Immunohistochemistry staining to ,1, ,2,1, or ,3,1 integrins was performed in arsenical keratosis and clinically normal perilesional skin. Western blotting was used to assess the expression of integrin ,1 and focal adhesion kinase (FAK) in arsenic-treated cultured keratinocytes. Results:, A decreased expression of ,1, ,2,1, or ,3,1 integrins was demonstrated in arsenical keratosis and clinical normal perilesional skin in a large proportion of arsenical keratosis cases studied. The expressions of integrin ,1 and FAK were both decreased in arsenic-treated keratinocytes. Conclusions:, Our results suggest that arsenic induces abnormal differentiation in arsenical keratosis via the effects of integrin expression in keratinocytes. [source] Speciation and distribution of arsenic and localization of nutrients in rice grainsNEW PHYTOLOGIST, Issue 1 2009E. Lombi Summary ,,Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. ,,Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC),inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (µ-XANES, µ-X-ray fluorescence (µ-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. ,,The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III),thiol complexes. ,,The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains. [source] Arsenic and thallium data in environmental samples: Fact or fiction?REMEDIATION, Issue 4 2010Susan D. Chapnick Matrix effects may increasingly lead to erroneous environmental decisions as regulatory limits or risk-based concentrations of concern for trace metals move lower toward the limits of analytical detection. A U.S. Environmental Protection Agency Office of Technical Standards Alert estimated that environmental data reported using inductively coupled plasma spectrometry (ICP-AES) has a false-positive rate for thallium of 99.9 percent and for arsenic of 25 to 50 percent. Although this does not seem to be widely known in the environmental community, using three case studies, this article presents data in environmental samples that demonstrate severe matrix effects on the accuracy of arsenic and thallium results. Case Study 1 involves soil results with concentrations that approached or exceeded the applicable regulatory soil cleanup objectives of 13 mg/kg for arsenic and 2 mg/kg for thallium. Reanalysis using ICP coupled with a mass spectrometer (ICP-MS) confirmed all thallium results were false positives and all arsenic results were biased high, concluding no action was required for soil remediation. Case Study 2 involves groundwater results for thallium at a Superfund site, where thallium was detected in groundwater up to 21.6 , g/L using ICP-AES. Reanalysis by ICP-MS reported thallium as nondetect below the applicable regulatory level in all samples. ICP-MS is usually a more definitive and accurate method of analysis compared to ICP-AES; however, this is not always the case, as we demonstrate in Case Study 3, using data from groundwater samples at an industrial site. Through a weight-of-evidence approach, it is demonstrated that although method quality control results were acceptable, interferences in some groundwater samples caused biased high results for arsenic using ICP-MS, which were significantly lower when reanalyzed using hydride generation atomic fluorescence spectrometry. Causes of these interference effects and conclusions from the three case studies to obtain accurate metal data for site assessment, risk characterization, and remedy selection are discussed. © 2010 Wiley Periodicals, Inc. [source] Use of Gold Nanoparticles in a Simple Colorimetric and Ultrasensitive Dynamic Light Scattering Assay: Selective Detection of Arsenic in Groundwater,ANGEWANDTE CHEMIE, Issue 51 2009Jhansi, Rani Kalluri Ganz wenig genügt: Der Gehalt von Arsen in Brunnenwasser in Bangladesh sowie in käuflichem Trinkwasser und in Leitungswasser im US-Staat Mississippi kann mithilfe eines Assays auf der Basis dynamischer Lichtstreuung (DLS) angezeigt werden. Die hochempfindliche und selektive colorimetrische Analyse (siehe Bild) weist Arsen in Konzentrationen von nur 3,ppt nach. [source] Coencapsulation of Arsenic- and Platinum-based Drugs for Targeted Cancer Treatment,ANGEWANDTE CHEMIE, Issue 49 2009Haimei Chen Zwei in einem: Eine neuartige Strategie für den effizienten Doppeleinschluss von Arsen- und Platin-Wirkstoffen in 100,nm große Liposomen (NBs) beruht auf der Bildung von PtII -AsIII -Addukten (siehe Bild). Das zweifach beladene System dient als robuste Plattform für weitere Modifizierungen mit zielgenauen Liganden und bietet einen Ansatz für die Verbesserung von Tumortherapeutika. [source] Preface: 10th International Symposium of the Japanese Arsenic Scientists' Society (JASS-10) on Natural and Industrial Arsenic, 29,30 November 2001, University Research Center Hall, Nihon University, Tokyo, JapanAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2002Article first published online: 8 JUL 200 No abstract is available for this article. [source] The Partitioning of Arsenic, Selenium, Cadmium, and Cesium during Pulverized Coal Combustion in a 17 kW Downflow CombustorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2001Wayne S. Seames The combustion of coal liberates arsenic, selenium, cadmium, and cesium into the environment. These toxic metals, which are discharged with the flue gas or collected with fly ash, may vaporize in the hot portions of the combustor then return to the solid phase in cooler zones of the process downstream. Understanding the mechanisms by which toxic metals partition between the vapor and solid phases is an important step for predicting and mitigating the effect of these metals upon the environment. An investigation of these partitioning mechanisms was performed. The results suggest that the dominant heterogeneous partitioning mechanism for transformation to the solid phase in the post-combustion zone is the reaction of metal vapor on the surface or within the pores of a supermicron ash particle for the Pittsburgh seam and Illinois #6 coals but not for the Ohio blend coal. A relationship between the concentration of supermicron phase arsenic, selenium, and cadmium to calcium was also observed, suggesting the formation of As-Ca, Se-Ca, and Cd-Ca reaction products. Selenium appears to be more reactive than arsenic for the formation of these calcium-based complexes. [source] Crystallization and preliminary X-ray crystallographic analysis of the ArsM arsenic(III) S -adenosylmethionine methyltransferaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Kavitha Marapakala Arsenic is the most ubiquitous environmental toxin and carcinogen and consequently ranks first on the Environmental Protection Agency's Superfund Priority List of Hazardous Substances. It is introduced primarily from geochemical sources and is acted on biologically, creating an arsenic biogeocycle. A common biotransformation is methylation to monomethylated, dimethylated and trimethylated species. Methylation is catalyzed by the ArsM (or AS3MT) arsenic(III) S -adenosylmethionine methyltransferase, an enzyme (EC 2.1.1.137) that is found in members of every kingdom from bacteria to humans. ArsM from the thermophilic alga Cyanidioschyzon sp. 5508 was expressed, purified and crystallized. Crystals were obtained by the hanging-drop vapor-diffusion method. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 84.85, b = 46.89, c = 100.35,Å, , = 114.25° and one molecule in the asymmetric unit. Diffraction data were collected at the Advanced Light Source and were processed to a resolution of 1.76,Å. [source] Mineralogical and Geochemical Constraints on Arsenic Mobility in a Philippine Geothermal FieldACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2006Chelo PASCUA Abstract, Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range of pH and redox conditions. [source] ChemInform Abstract: Theoretical Investigation of Clusters of Phosphorus and Arsenic: Fascination and Temptation of High Symmetries.CHEMINFORM, Issue 30 2008Paola Nava Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Two Unprecedented Inorganic,Organic Boxlike and Chainlike Hybrids Based on Arsenic,Vanadium Clusters Linked by Nickel Complexes.CHEMINFORM, Issue 21 2007Yanfei Qi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Icosahedral and Ring-Shaped Allotropes of ArsenicCHEMPHYSCHEM, Issue 16 2007Antti J. Karttunen Dr. Abstract We predict the existence of two novel families of arsenic nanostructures: icosahedral cages and ring-shaped chains. Quantum chemical calculations on the cages, rings, and the experimentally known allotropes of arsenic suggest the nanostructures to be thermodynamically stable. The icosahedral cages are modifications of the gray allotrope of arsenic, while the ring-shaped chains are structurally related to the red allotrope of phosphorus. Comparisons between the analogous allotropes of arsenic and phosphorus show distinct differences. While phosphorus favors the ring-shaped chains over the icosahedral cages, large cages become favorable for arsenic. From the thermodynamical point of view, experimental preparation of the proposed families of arsenic nanostructures is expected to be viable. [source] Environmental Risk Factors Predisposing to the Development of Basal Cell CarcinomaDERMATOLOGIC SURGERY, Issue 2004Malgorzata Zak-Prelich MD Background. Basal cell carcinomas (BCCs) are the most common malignancies in white people. The incidence varies depending on the region of the world, with the highest rate of 1% to 2% per year noted in Australia. It is estimated that BCC incidence increases by 5% annually. An increasing incidence of BCC is in line with the changes in the living style and exposure to various environmental factors. Objective. To present the environmental factors that may influence the development of BCCs. The influence of ultraviolet radiation exposure alone and in connection with immunosuppression, smoking, occupational factors, as well as arsenic and ionizing radiation exposure, was described. Conclusion. BCC is a very complex disease, with many factors influencing its development. Environmental factors are very important for the prevalence of BCC, and most of them can be avoided. The exposure to ultraviolet radiation is undoubtedly of great risk; therefore, the national campaigns against aggressive, seasonal sun exposure, especially in children and adolescents, as well as using sunscreens, are of great value in the fight against BCC development. [source] Analysis and Speciation of Traces of Arsenic in Environmental, Food and Industrial Samples by Voltammetry: a ReviewELECTROANALYSIS, Issue 9 2004Andrea Cavicchioli Abstract Voltammetric approaches for the determination of arsenic and speciation at trace levels are critically appraised in a review covering the literature from 1970 to 2002. Special attention is devoted to stripping modes and to issues related to the choice of working material and supporting electrolyte. A section is dedicated to the management of real samples and aspects of sample preparation. An extensive compilation, organized by real sample type, gathers essential experimental conditions. Potentiometric stripping analysis is introduced for sake of comparison. The coupling of voltammetric detection or preaccumulation with FIA, chromatography, capillary electrophoresis and ICP techniques is also addressed. [source] | |||||||||||||||||||||||||||||||||||||