Showing papers on "Arsenic published in 1994"
TL;DR: The concentration of arsenic in natural iron oxyhydroxides and oxide minerals extracted from soils at the Ashanti mine, Ghana, and was found to vary from 2 to 35,600 mg/kg as discussed by the authors.
580 citations
TL;DR: Arsenic removal during coagulation or Fe-Mn oxidation is examined to aid utilities that desire to improve arsenic removal in this paper, where fundamental mechanisms of arsenic removal are discussed, optimization strategies are forwarded, and some new insights are provided to guide future research.
Abstract: Arsenic removal during coagulation or Fe-Mn oxidation is examined to aid utilities that desire to improve arsenic removal. Fundamental mechanisms of arsenic removal are discussed, optimization strategies are forwarded, and some new insights are provided to guide future research. Specifically, As(III) removals by coagulation are primarily controlled by coagulant dose and relatively unaffected by solution pH, whereas the converse is true for As(V).
370 citations
TL;DR: Bacterial plasmids conferring arsenic resistance encode specific efflux pumps able to extrude arsenic from the cell cytoplasm thus lowering the intracellular concentration of the toxic ions.
Abstract: Arsenic ions, frequently present as environmental pollutants, are very toxic for most microorganisms. Some microbial strains possess genetic determinants that confer resistance. In bacteria, these determinants are often found on plasmids, which has facilitated their study at the molecular level. Bacterial plasmids conferring arsenic resistance encode specific efflux pumps able to extrude arsenic from the cell cytoplasm thus lowering the intracellular concentration of the toxic ions. In Gram-negative bacteria, the efflux pump consists of a two-component ATPase complex. ArsA is the ATPase subunit and is associated with an integral membrane subunit, ArsB. Arsenate is enzymatically reduced to arsenite (the substrate of ArsB and the activator of ArsA) by the small cytoplasmic ArsC polypeptide. In Gram-positive bacteria, comparable arsB and arsC genes (and proteins) are found, but arsA is missing. In addition to the wide spread plasmid arsenic resistance determinant, a few bacteria confer resistance to arsenite with a separate determinant for enzymatic oxidation of more-toxic arsenite to less-toxic arsenate. In contrast to the detailed information on the mechanisms of arsenic resistance in bacteria, little work has been reported on this subject in algae and fungi.
333 citations
309 citations
TL;DR: The role of reduced glutathione in the metabolism of arsenic is consistent with the previously described effects of this agent on the organismic toxicity of arsenic.
292 citations
TL;DR: The groundwaters collected from three wells in the Blackfoot disease (BFD) area in southwest Taiwan contain, on the average, 671 149 [mu]g of total dissolved arsenic/L, and the predominant arsenic species in the well waters of the BFD area is As[sup 3+].
Abstract: The groundwaters collected from three wells in the Blackfoot disease (BFD) area in southwest Taiwan contain, on the average, 671 149 [mu]g of total dissolved arsenic/L. The arsenic contents in the well waters of Hsinchu, a city in the northwest of the island where no BFD has ever been reported, are less than 0.7 [mu]g/L. The predominant arsenic species in the well waters of the BFD area is As[sup 3+] with an average As[sup 3+]/As[sup 5+] ratio of 2.6. The methyl arsenicals, monomethylarsinic acid and dimethylarsonic acid, are below detection limits ( 300 000 Da. The results obtained from the BFD area are compared with similar arsenic studies conducted in the United States. The importance of arsenic speciation in environmental water studies and the possible cause of BFD are discussed. 21 refs., 1 fig., 3 tabs.
282 citations
TL;DR: In this paper, the authors showed that 3% v/v methanol in the analyte solutions doubled the level of the background signal for arsenic and selenium, but its fluctuation (noise) was not increased.
Abstract: Addition of carbon as methanol or ammonium carbonate to the aqueous analyte solutions in combination with increased plasma power input enhanced the inductively coupled plasma mass spectrometry (ICP-MS) signal intensities of arsenic and selenium. In the presence of the optimum 3% v/v methanol concentration the signal intensities achieved were about 4500–5000 counts s–1 per ng ml–1 of arsenic and about 700–1100 counts s–1 per ng ml–1 of selenium (82Se), corresponding to enhancement factors of 3.5–4.5 compared with aqueous solution for the two elements. Differences in sensitivity (calculated on the basis of analyte atom) were observed between the individual arsenic species and between the selenium species in aqueous as well as in carbon-added solutions. The presence of 3% v/v methanol in the analyte solutions doubled the level of the background signal for arsenic and selenium, but its fluctuation (noise) was not increased. Therefore, the observed increase in analyte sensitivity led to a similar increase in signal-to-noise ratio. The addition of carbon as ammonium carbonate enhanced the arsenic signal by a similar factor but caused severe contamination of the ICP-MS instrument by carbon. In the 3% v/v methanol solutions of arsenic and selenium the signal intensity from antimony (internal standard) was enhanced by a factor of 1.5, which indicates that the enhancement effect of the arsenic and selenium signals by methanol is only to a limited extent caused by improved sample transport/nebulization efficiency. It is proposed that an increased population of carbon ions or carbon-containing ions in the plasma facilitates a more complete ionization of analytes lower in ionization energy than carbon itself. The enhanced detection power for arsenic was applied to arsenic speciation by high-performance liquid chromatography (HPLC)–ICP-MS, and made possible the detection of the arsenocholine ion (AsC) in extracts of shrimp at the 5–10 ng g–1 concentration level. The limit of detection was improved by a factor of 3.4 after addition of methanol and was 4.7 ng g–1 as the AsC ion.
276 citations
TL;DR: In this paper, the use of enhanced coagulation for arsenic removal was examined at the facilities of a California utility in 1992 and 1993, with two source waters, and the results showed that for the source waters tested, enhanced co-agulation could be effective for the arsenic removal and that less ferric chloride than alum is needed to achieve the same removal.
Abstract: The possible use of enhanced coagulation for arsenic removal was examined at the facilities of a California utility in 1992 and 1993. The tests were conducted at bench, pilot, and demonstration scales, with two source waters. Alum and ferric chloride, with cationic polymer, were investigated at various influence arsenic concentrations. The investigators concluded that for the source waters tested, enhanced coagulation could be effective for arsenic removal and that less ferric chloride than alum, on a weight basis, is needed to achieve the same removal.
272 citations
TL;DR: The marmoset monkey is the only species which has been shown unable to methylate inorganic arsenic, and in contrast to other species, the rat shows a marked binding of DMA to the hemoglobin, which results in a low rate of urinary excretion of arsenic.
Abstract: Humans are exposed via air, water and food to a number of different arsenic compounds, the physical, chemical, and toxicological properties of which may vary considerably. In people eating much fish and shellfish the intake of organic arsenic compounds, mainly arsenobetaine, may exceed 1000 μg As per day, while the average daily intake of inorganic arsenic is in the order of 10–20 μg in most countries. Arsenobetaine, and most other arsenic compounds in food of marine origin, e.g. arsenocholine, trimethylarsine oxide and methylarsenic acids, are rapidly excreted in the urine and there seem to be only minor differences in metabolism between animal species. Trivalent inorganic arsenic (AsIII) is the main form of arsenic interacting with tissue constituents, due to its strong affinity for sulfhydryl groups. However, a substantial part of the absorbed AsIII is methylated in the body to less reactive metabolities, methylarsonic acid (MMA) and dimethylarsinic acid (DMA), which are rapidly excreted in the urine. All the different steps in the arsenic biotransformation in mammals have not yet been elucidated, but it seems likely that the methylation takes place mainly in the liver by transfer of methyl groups from S-adenosylmethionine to arsenic in its trivalent oxidation state. A substantial part of absorbed arsenate (AsV) is reduced to AsIII before being methylated in the liver. There are marked species differences in the methylation of inorganic arsenic. In most animal species DMA is the main metabolite. Compared with human subjects, very little MMA is produced. The marmoset monkey is the only species which has been shown unable to methylate inorganic arsenic. In contrast to other species, the rat shows a marked binding of DMA to the hemoglobin, which results in a low rate of urinary excretion of arsenic.
236 citations
TL;DR: It seems that arsenosugars are not decomposed by stomach acid and that reactions involving enzymatic and (or) microbial activity in the human body may be responsible for the metabolism of arsenosUGars.
Abstract: We studied chemical speciation of arsenic compounds in urine samples by using HPLC with inductively coupled plasma mass spectrometry detection. We examined urinary arsenic excretion patterns and the arsenic species excreted from nine human subjects who ingested seaweed products and crab (or shrimp). Fast urinary excretion of unchanged arsenobetaine was seen after ingestion of crab and shrimp, which contain arsenobetaine as the major arsenic species. In contrast, the arsenosugars, which comprise the major arsenic species in seaweed, are metabolized and have a longer retention time in the human body. When nine volunteers ingested the commercial seaweed product nori, both the urinary arsenic excretion pattern and the excreted arsenic species varied from individual to individual, and as many as six metabolites could be detected. It seems that arsenosugars are not decomposed by stomach acid and that reactions involving enzymatic and (or) microbial activity in the human body may be responsible for the metabolism of arsenosugars.
31 Dec 1994
TL;DR: In this paper, the authors identify the natural and anthropogenic sources of arsenic in the environment, including coal combustion by products and sewage sludge, and discuss arsenic concentrations in natural soils.
Abstract: The paper identifies the natural and anthropogenic sources of arsenic in the environment. Anthropogenic sources include mining and smelting activities, pesticide use, coal, coal combustion by products and sewage sludge. It goes on to discuss arsenic concentrations in natural soils, speciation of arsenic in the soil environment, and arsenic in pyritic mine spoils and inland acid sulfate soils, arsenic concentrations in arsenic-contaminated soils, and arsenic in coal and coal combustion residues applied to land. Further sections cover arsenic in sediments, groundwater contamination with arsenic, and arsenic in higher plants. 178 refs., 3 figs., 3 tabs.
25 Apr 1994
TL;DR: Nagase et al. as mentioned in this paper described the structural chemistry of organic compounds containing Arsenic, Antimony and Bismuth, and showed that the properties of these compounds are similar to those of As, Sb and Bi.
Abstract: Partial table of contents: General and Theoretical Aspects (S. Nagase). Structural Chemistry of Organic Compounds Containing Arsenic, Antimony and Bismuth (D. Sowerby). Detection, Identification and Determination (T. Crompton). Mass Spectra of the Organometallic Compounds of As, Sb and Bi (Y. Nekrasov & D. Zagorevskii). Substituent Effects of Arsenic, Antimony and Bismuth Groups (M. Charton). Thermochromism of Organometallic Derivatives Containing As, Sb or Bi (H. Breunig). Electrochemistry (M. Nielsen). Thermolysis (C. McAuliffe & A. Mackie). Syntheses and Uses of Isotopically Labelled Compounds of Bismuth, Antimony and Arsenic (M. Zielinski & M. Kanska). The Biochemistry of Arsenic, Bismuth and Antimony (K. Dill & E. McGown). Safety and Environmental Effects (S. Maeda). Indexes.
Journal Article•
TL;DR: Evidence is provided that chronic ingestion of high levels of inorganic arsenic in drinking water is associated with an increased frequency of micronucleated bladder cells, consistent with a genotoxic effect of arsenic on bladder cells.
Abstract: It is well established that inorganic arsenic is causally associated with lung cancer via inhalation and skin cancer via ingestion. Epidemiological evidence based on studies in Taiwan suggests that ingestion of inorganic arsenic may also cause other more fatal internal cancers, with the highest relative risks reported for bladder cancer. Here, we have used a biological marker of response, the micronucleus assay in exfoliated bladder cells, to evaluate the possible genotoxic effects of chronic arsenic ingestion on the bladder. The overall objective of this study was to compare the frequency of micronucleated cells in exfoliated bladder and buccal cells between a group of 18 individuals in Nevada who chronically ingested high levels of inorganic arsenic from their well water (average level, 1,312 micrograms/liter) and an individually matched control group with low exposure to arsenic (average level, 16 micrograms/liter). A 1.8-fold increase (90% confidence interval, 1.06-2.99) was observed in the weighted mean frequency of micronucleated bladder cells in the exposed group (2.79 per 1000 cells) compared with the unexposed group (1.57 per 1000 cells). In addition, the frequency of micronucleated bladder cells was positively associated with the urinary concentration of inorganic arsenic plus its methylated metabolites (Spearman correlation = 0.33; P = 0.03). In contrast, there was no increase in micronucleated buccal cells associated with arsenic ingestion (frequency ratio = 1.0; 90% confidence interval, 0.65-1.53). The results of this study provide evidence that chronic ingestion of high levels of inorganic arsenic in drinking water is associated with an increased frequency of micronucleated bladder cells. These findings are consistent with a genotoxic effect of arsenic on bladder cells, but a larger study is needed to confirm them.
TL;DR: In this article, it was demonstrated that X-ray absorption fine structure (XAFS) spectroscopy is capable of providing speciation information at realistic concentration levels of 10-100 ppm, provided a solid-state multielement germanium detector is used.
TL;DR: Using directly coupled high performance liquid chromatography-inductively coupled plasma mass spectrometry, non-toxic arsenobetaine was identified as the major arsenic species in cod, dab, haddock, mackerel, plaice and whiting.
Abstract: Using directly coupled high performance liquid chromatography–inductively coupled plasma mass spectrometry, non-toxic arsenobetaine was identified as the major arsenic species in cod, dab, haddock, mackerel, plaice and whiting. The fish was caught in coastal waters around Plymouth, UK and purchased from local markets. Arsenic levels ranged between 1.0 mg kg–1 dry mass, in the mackerel, to 187 mg kg–1 dry mass, in the plaice. Mackerel also contained dimethylarsinic acid (DMAA) and possibly a lipid bound arsenic species. Levels of the toxic inorganic species were low in all cases. No monomethylarsonic acid was recorded in any of the fish. No degradation of arsenobetaine to more toxic species was observed when an enzymic digestion procedure, based on the action of trypsin, was applied to the fish, with the possible exception of one of the plaice samples for which DMAA was characterized in the digest at the mg kg–1 level. For total arsenic determinations, nitrogen addition ICP-MS was used to overcome the potential interference from 40Ar35Cl+. The results obtained compared well with certified values for the dogfish reference material DORM-1.
TL;DR: An arsenic specific detection system utilizing on-line microwave digestion and hydride generation atomic absorption spectrometry (MD/HGAAS) is described for arsenic speciation by using high performance liquid chromatography (HPLC).
TL;DR: The data on sister-chromatid exchanges showed that arsenic at concentrations used by the population (0.13 mg/l) induced a significantly elevated response, and other health effects of arsenic at these concentrations were found, e.g., hyperkeratosis, melanosis, actinic ker atosis, basal cell carcinoma.
Abstract: A study was carried out on human subjects of various ages and backgrounds who had been drinking water containing more than 0.13 mg/l (0.13 ppm) arsenic for a period of at least 20 years. The main aim was not only to correlate the frequency of sister-chromatid exchanges in the lymphocytes with the amount of arsenic in water and urine but also to correlate the frequency of SCE with sex and age. In addition, family background regarding skin alterations or other arsenic-related symptoms was explored, so that individual health conditions could be assessed. External factors such as exposure to other chemical or contaminating agents (pesticides, battery manufacturing plants, foundries) were also taken into consideration. The data on sister-chromatid exchanges (282 exposed and 155 control individuals) showed that arsenic at concentrations used by our population (0.13 mg/l) induced a significantly elevated response. Other health effects of arsenic at these concentrations were found, e.g., hyperkeratosis, melanosis, actinic keratosis, basal cell carcinoma.
TL;DR: The vertical distribution of Pb and As was examined in six contaminated orchard soils in the State of Washington, USA as discussed by the authors, with Pb concentration maxima ranging from 2.15 to 10.69 mmol/kg, and As concentration minima varying from 0.77 to 4.85 mmol/ kg.
Abstract: Many deciduous fruit tree orchard sites throughout the world are contaminated with lead (Pb) and arsenic (As) from past use of lead arsenate insecticides. The vertical distribution of Pb and As was examined in six contaminated orchard soils in the State of Washington, USA. Most of the Pb and As was restricted to the upper 40 cm of soil, with Pb concentration maxima ranging from 2.15 to 10.69 mmol/kg, and As concentration maxima ranging from 0.77 to 4.85 mmol/kg. In all cases, there were lower Pb and As concentrations at the soil surface than deeper in the profile. Arsenic was depleted relative to Pb in the topsoils and was enriched relative to Pb in the subsoils, suggesting that there has been preferential movement of As. Absolute soil enrichment with Pb occurred to depths between 15 and 50 cm. Absolute soil enrichment with As occurred to depths between 45 and > 120 cm. At 120 cm, Pb concentrations were < 0.05 mmol/kg, and As concentrations ranged from 0.07 to 0.63 mmol/kg. The deeper movement of Pb and As in the study soils relative to that reported for lead arsenate-contaminated soils elsewhere is attributed to high loading rates of lead arsenate, coarse soil texture, low organic matter content, and use of irrigation. The results indicate that Pb and As concentrations in lead arsenate-contaminated soils are high enough to be of potential environmental concern. The amount of As redistribution appears to be substantial enough to preclude some methods of remediation and to create potential risk of contamination of underlying shallow groundwater.
TL;DR: In this article, the authors compared the leaching of As and Se from fly ash with the sorption of arsenate and selenite on hematite, portlandite and mullite.
TL;DR: In this paper, a new approach was described for the speciation of arsenic species including trivalent methylarsenicals in natural waters, and the detection limits for the trivalents were about 13-17 pM.
Abstract: A new approach is described for the speciation of arsenic species including trivalent methylarsenicals in natural waters. Arsenious acid [As(III)]; monomethylarsonous acid [MMAA(III)], and dimethylarsinous acid [DMAA(III)] are separated from pentavalent species by solvent extraction using diethylammonium diethyldithiocarbamate (DDDC) and determined by hydride generation atomic absorption spectrometry (HG-AAS) after cold trapping and chromatographic separation. The detection limits for the trivalent species are about 13-17 pM. The sum of concentrations of the trivalent and pentavalent species are determined directly by HG-AAS in aliquots of the same samples. This is the first report of trivalent methylarsenicals being found and measured in natural waters
TL;DR: Arsenosugars were identified as the major arsenic compounds present in marine algae, whereas arsenobetaine was the dominant arsenic species present in crab and skimp.
Abstract: Speciation of arsenic compounds in some marine algae, bivalves, and crustaceans was studied by using two techniques: (i) high-performance liquid chromatography with inductively coupled plasma mass spectrometry detection and (ii) hydride generation atomic adsorption spectrometry following microwave-assisted digestion. Arsenosugars were identified as the major arsenic compounds present in marine algae, whereas arsenobetaine was the dominant arsenic species present in crab and skimp. In contrast to most previous reports, which claimed arsenobetaine as the only major arsenic species present in marine bivalves, tits study revealed the presence of arsenosugars in addition to arsenobetaine in the bivalves
TL;DR: In this paper, the use of hydride generation techniques for arsenic species is shown to be pH dependent and the optimum conditions for the determination of these arsenic species are in the same range, and a single arsenic species can be used for calibration.
TL;DR: In the Ashanti Au mine in southwest Ghana, arsenopyrite constitutes an important part of the hypogene ore assemblage, often hosting significant concentrations of Au as discussed by the authors.
Book•
01 Jan 1994
TL;DR: Azcue et al. as mentioned in this paper presented a survey of the history of the use of arsenic in aquatic organisms and their relationship with aquatic organisms and showed that the chemical forms of arsenic in Aquatic Organisms and their interrelationships are well-known.
Abstract: Partial table of contents: Arsenic: Historical Perspectives (J. Azcue & J. Nriagu). Arsenic Distribution in Soils (H. Yan-Chu). Arsenic Mobilization and Bioavailability in Soils (D. Bhumbla & R. Keefer). Mobilization of Arsenic in Contaminated River Waters (W. Mok & C. Wai). Removal of Arsenic in Drinking Water Treatment (M. Jekel). Biotransformation of Arsenic in the Freshwater Environment (S. Maeda). The Chemical Forms of Arsenic in Aquatic Organisms and Their Interrelationships (D. Phillips). Arsenic in Several Chinese Estuaries and Coastal Seas (L. Xiankun, et al.). Arsenic in Vegetation of Wetlands (M. Otte & W. Ernst). Arsenic Minerals Formed at Low Temperatures (F. Schaufelberger). Index.
TL;DR: In this article, the arsenic pressure dependence of Ga adatom surface diffusion in molecular beam epitaxy (MBE) on nonplanar substrates was investigated by using in situ scanning microprobe reflection high-energy electron diffraction (µ-RHEED).
Abstract: The arsenic pressure dependence of Ga adatom surface diffusion in molecular beam epitaxy (MBE) on nonplanar substrates was investigated. By using in situ scanning microprobe reflection high-energy electron diffraction (µ-RHEED), the distribution of the growth rate of GaAs on the (001) surface near the edge of the (111)A or (111)B sidewall was measured under various arsenic pressures. The surface diffusion length of Ga adatom incorporation on the (001) surface derived from the distribution is on the order of micrometers and it shows a strong dependence on arsenic pressure. A simple model based on one-dimensional surface diffusion was proposed. With this theory, the lifetime of Ga adatom incorporation on other surfaces is obtained.
TL;DR: Polyphysa peniculus did not metabolize dimethylarsinic acid when it was used as a substrate, and significant amounts of more complex arsenic species, such as arsenosungars, were not observed in the cells or medium on the evidence of flow injection–microwave digestion–hydride generation–atomic absorption spectrometry methodology.
Abstract: Polyphysa peniculus was grown in artificial seawater in the presence of arsenate, arsenite, monomethylarsonate and dimethylarsinic acid. The separation and identification of some of the arsenic species produced in the cells as well as in the growth medium were achieved by using hydride generation–gas chromatography–atomic absorption spectrometry methodology. Arsenite and dimethylarsinate were detected following incubation with arsenate. When the alga was treated with arsenite, dimethylarsinate was the major metabolite in the cells and in the growth medium; trace amounts of monomethylarsonate were also detected in the cells. With monomethylarsonate as a substrate, the metabolite is dimethylarsinate. Polyphysa peniculus did not metabolize dimethylarsinic acid when it was used as a substrate. Significant amounts of more complex arsenic species, such as arsenosungars, were not observed in the cells or medium on the evidence of flow injection–microwave digestion–hydride generation–atomic absorption spectrometry methodology. Transfer of the exposed cells to fresh medium caused release of most cell–associated arsenicals to the surrounding environment.
TL;DR: The data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels.
Abstract: In a group of 43 smelter workers exposed to inorganic arsenic dust for 13-45 years, nerve conduction velocities (NCVs) were significantly lower in two peripheral nerves as compared with matching referents. With multivariate data analysis, a significant negative correlation was found between cumulative absorption of arsenic and NCV in four examined nerves and the sural amplitude. Clinical symptoms of neuropathy and other symptoms related to arsenic exposure were moderate, though the difference between the groups was significant. The mean total absorption of arsenic was calculated to be less than 5 g, and the maximal absorption about 20 g. These data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels. © 1994 Wiley-Liss, Inc.
TL;DR: The in vitro model appears to be valid for further study of these arsenite-binding proteins and the radioactive profiles after gel filtration chromatography of liver cytosolic proteins are very similar whether As3+ binding occurs in vitro or in vivo.