Showing papers on "Arsenic published in 1995"
TL;DR: In six districts of West Bengal arsenic has been found in ground water above the maximum permissible limit recommended by the WHO, and more than 175,000 people are showing arsenical skin lesions that are the late stages of manifestation of arsenic toxicity.
Abstract: In six districts of West Bengal arsenic has been found in ground water above the maximum permissible limit recommended by the WHO of 0.05 mg l–1. This water is used by the villagers for drinking, cooking and other household purposes. These six districts have an area of 34 000 km2 and hold a population of 30 million. Over the last five years we have surveyed only a few small areas of these six affected districts and our survey revealed that, at present, at least 800 000 people from 312 villages in 37 blocks are drinking contaminated water and more than 175 000 people are showing arsenical skin lesions that are the late stages of manifestation of arsenic toxicity. Most of the three stages of arsenic-related clinical manifestations are observed amongst the affected people. The common symptoms are conjunctivitis, melanosis, depigmentation, keratosis and hyperkeratosis; cases of gangrene and malignant neoplasms are also observed. The source of arsenic is geological. We have analysed thousands of arsenic contaminated water samples. Most of the water samples contain a mixture of arsenite and arsenate and in none of them could we detect methylarsonic or dimethylarsinic acid. We have also analysed a large number of urine, hair and nail samples, several skin-scales and some liver tissues (biopsy samples) of the people drinking the arsenic contaminated water and showing arsenical skin lesions. Flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) was used for the analysis of hair, nails, urine and skin-scale after decomposition by various techniques. The liver tissues were analysed by Zeeman corrected-ETAAS using a few milligrams of the biopsy samples.
547 citations
TL;DR: Arsenic in ground water has been found above the maximum permissible limit in six districts of West Bengal covering an area of 34 000 km2 with a population of 30 million as mentioned in this paper.
Abstract: Arsenic in ground water has been found above the maximum permissible limit in six districts of West Bengal covering an area of 34 000 km2 with a population of 30 million. At present 37 blocks of these six districts by the side of the River Ganga are affected and about 800 000 people from 312 villages/wards are drinking arsenic contaminated water and amongst them at least 175 000 people are showing arsenical skin lesions. The source of arsenic is geological. We have analysed thousands of tube-well water samples from these six districts for four arsenic species namely, arsenite, arsenate, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). We could detect no MMAA or DMAA in any of these samples. In urine, DMAA and MMAA are the predominant species along with arsenite and arsenate. The techniques we used for the determination and speciation of arsenic are: (i) separation of arsenite and arsenate from water by sodium diethyldithiocarbamate in chloroform followed by FI-HGAAS; (ii) spectrophotometry using Ag–DDTC in chloroform with hexamethylenetetramine as absorbing solution; (iii) ion-exchange separation of arsenite and arsenate from water followed by FI-HGAAS; and (iv) for analysis of inorganic arsenic and its metabolites in urine, FI-HGAAS was used after separation of the species by a combined cation–anion-exchange column. Total arsenic in urine was determined by FI-HGAAS after acid decomposition. The most toxic species, arsenite, is present in ground water at about 50% of the total arsenic level, and more than 90% of the total arsenic in urine is inorganic arsenic and its metabolites.
522 citations
TL;DR: In this paper, a second order rate law with respect to arsenate(III)-oxidation was studied and it was concluded that the enhanced oxidation after this initial period is caused by bacteria, as some ubiquitous bacteria are involved in managanese oxidation.
334 citations
TL;DR: X-ray photoelectron spectroscopy (XPS) of an unoxidized surface reveals that sulphur is present as disulphide (S22−, 78 At%), monosulphides (S2−, 15%), and as polysulphite (Sn2−), where 2 < n < 8) As1− predominates, but 15% As0 is also observed.
308 citations
TL;DR: The Dimaval-mercury challenge test holds great promise as a diagnostic test for mercury exposure, especially for low level mercurialism.
255 citations
TL;DR: In this article, it was found that As(V) is more effectively removed from solution by using activated carbon with a high ash content, whereas As(II) is also adsorbed independently of the impregnated copper.
232 citations
TL;DR: The metabolism of inorganic arsenic (As) in native women in four Andean villages in north-western Argentina with elevated levels of As in the drinking water has been investigated, and arsenic was excreted in the urine mainly as inorganic As and DMA.
222 citations
TL;DR: In this article, the feasibility of inducing As(III) precipitation through bacterial reduction of sulfate was evaluated in laboratory microcosms established under strictly anaerobic conditions, where As(lII), Fe(II), and sulfate concentrations were routinely monitored in the aqueous phase as sulfates was reduced to sulfide.
Abstract: Contaminated sediments from the Milltown Reservoir in western Montana release arsenic and various heavy metals (eg, Cu, Cd, Pb, Zn, Mn) into an underlying alluvial aquifer as redox conditions in the sediments change with seasonally fluctuating water levels Porewater analyses indicate that sulfate is depleted with depth In this study, the feasibility of inducing As(III) precipitation through bacterial reduction of sulfate was evaluated in laboratory microcosms established under strictly anaerobic conditions As(lII), Fe(II), and sulfate concentrations were routinely monitored in the aqueous phase as sulfate was reduced to sulfide Both As(III) and Fe(II) concentrations in the sediment microcosms decreased as sulfide was made available Energy‐dispersive x‐ray (EDS) analysis indicated that some of the arsenic was precipitated as an iron‐arsenic‐sulfide solid phase The precipitation of arsenic observed in this laboratory study suggests that bacterial sulfate reduction may be a process by which heavy met
189 citations
TL;DR: In this article, the response of tomato plants to different levels of arsenic (As) in nutrient solution was investigated, the processes of uptake, distribution and accumulation of As, and the effect of arsenite on yield and plant growth.
Abstract: The response of tomato (Lycopersicum esculentum Mill, cultivar Marmande) plants to different levels of arsenic (As) in nutrient solution was investigated—the processes of uptake, distribution and accumulation of As, and the effect of arsenite on yield and plant growth (plant height, diameter of stem, stem and root length, fresh and dry weight of root, stems, leaves, and fruit). The experiment was performed at three levels of As: 2, 5 and 10 mg/L [added as sodium arsenite (NaAsO2)] in a nutrient solution, together with the corresponding control plants. Arsenic uptake depended on the As concentration in solution and As content in the roots increased as the time of treatment increased. The most important finding was the high toxicity of arsenite to roots. The concentration in stems, leaves, and fruit was correlated with the As level in the nutrient solution. Although the As level of 10 mg/L damaged the root membranes, resulting in a significant decrease in the upward transport of As. Arsenic exposur...
171 citations
TL;DR: In this paper, the vertical profiles for dissolved antimony, arsenic, and selenium were obtained at four stations in the eastern basins of the North and South Atlantic Ocean, and on a surface-water transect from 24 ° S to 31 ° N.
156 citations
TL;DR: Arsenic profiles were obtained from full-scale conventional treatment (coagulation, Fe-Mn oxidation, or softening) plants, facilitating testing of theories regarding arsenic removal as mentioned in this paper.
Abstract: Arsenic profiles were obtained from full-scale conventional treatment (coagulation, Fe-Mn oxidation, or softening) plants, facilitating testing of theories regarding arsenic removal. Soluble As(V) removal efficiency was controlled primarily by pH during coagulation, be Fe{sup +2} oxidation and Fe(OH){sub 3} precipitation during Fe-Mn oxidation, and by Mg(OH){sub 2} formation during softening. Insignificant soluble As(V) removal occurred during calcite precipitation at softening plants or during Mn{sup +2} oxidation-precipitation at Fe-Mn oxidation plants. The extent of soluble As(V) removal during coagulation and softening treatments was lower than expected. Somewhat surprisingly, during coagulation As(V) removal efficiencies were limited by particulate aluminum formation and removal, because much of the added coagulant was not removed by 0.45-{mu}m-pore-size filters. At one utility, reducing the coagulation pH from 7.4 to 6.8 (at constant alum dose) improved removal of particulate aluminum, thereby enhancing soluble As(V) removal during treatment.
TL;DR: In this paper, the authors evaluated the removal of naturally occurring arsenic in a full-scale (106-mgd) conventional treatment plant and found that arsenic removal was 81-96% (ferric chloride) and 23-71% (alum).
Abstract: This study evaluated the removal of naturally occurring arsenic in a full-scale (106-mgd) conventional treatment plant. When the source water was treated with 3--10 mg/L of ferric chloride or 6, 10, or 20 mg/L of alum, arsenic removal was 81--96% (ferric chloride) and 23--71% (alum). Metal concentrations in the sludge produced during this study were below the state`s current hazardous waste levels at all coagulant dosages. No operational difficulties were encountered.
TL;DR: In this paper, the forms of occurrence of the trace elements arsenic, mercury, selenium, zinc, chromium, and antimony were determined by successive chemical extractions of both a bituminous and a subbituminous coal.
Abstract: The extent of vaporization and subsequent recondensation of many trace elements during coal combustion is believed to depend upon the form of occurrence of the trace element in coal. To test this hypothesis, the forms of occurrence of the trace elements arsenic, mercury, selenium, zinc, chromium, and antimony were determined by successive chemical extractions of both a bituminous and a subbituminous coal. Well-controlled laboratory combustion tests were then conducted, and the concentrations of each element measured as a function of flyash particle size. Results indicated that those elements associated with the coal organic matrix, either ion-exchanged or covalently bound, and those associated with the reactive mineral pyrite were highly volatile. Arsenic, selenium, mercury, and antimony provide examples. In contrast, elements that were associated with silicate or oxide minerals (e.g., chromium) were relatively nonvolatile. For all elements, but particularly zinc, differences in form of occurrence between the two coals led to differences in fraction volatilized. For arsenic and selenium, the results indicated that the condensation pathway was dependent upon flyash chemistry. Using thermochemical equilibrium modeling to interpret the experimental data, it was concluded that arsenic vapors reacted to form calcium arsenates during combustion of the high-calcium subbituminous coal, but condensed as arsenic oxide during combustion of the low-calcium bituminous coal. Limited (calcium) selenate formation was also inferred from the data.
TL;DR: Data indicate that sodium arsenite has an aneuploidogenic and a mitotic arrestant effect and is confirmed with the chromosome aberrations levels induced by arsenic in the same donors.
Abstract: Arsenic is a well known carcinogenic environmental pollutant although its mechanism of action remains unknown. Since alterations in chromosome segregation have been observed in individuals exposed to high concentrations of arsenic in the drinking water, the aneuploidogenic potential of arsenic was evaluated in vitro. Whole blood cultures were incubated for 72 h and treated with various concentrations of sodium arsenite for the last 24 h. Cells were harvested and samples were processed specially for aneuploidy evaluation. The number of chromosomes in 200 metaphases of first and second division cells was scored. A dose-related effect was observed: the highest concentration (10−2 μM) induces 28.33% and 22.4% hyperploid cells in first and second division respectively and 29% tetraploid cells. The colchicine-like effect of arsenic was also evaluated. Mitotic arrest was evaluated in cultures treated for the last 2 h. Sodium arsenite can produce 40.24% and 12.93% of the colcemid effect (mitotic arrestant effect at 10−2 μM and 10−10 μM respectively). A different individual susceptibility effect was observed in both parameters and confirmed with the chromosome aberrations levels induced by arsenic in the same donors. Data indicate that sodium arsenite has an aneuploidogenic and a mitotic arrestant effect.
TL;DR: Arsenic species in arsenic accumulating mush- rooms (Sarcosphaera coronaria, Laccaria amethystina, Sarcodon imbricatum, Entoloma lividum,Agaricus haemorrhoidaius, Agaricus placomyces, Lycoperdon perlatum) were determined.
Abstract: Arsenic species in arsenic accumulating mush- rooms (Sarcosphaera coronaria, Laccaria amethystina, Sarcodon imbricatum, Entoloma lividum, Agaricus haemorrhoidaius, Agaricus placomyces, Lycoperdon perlatum) were determined. HPLC/ICP MS and ion-exchange chromatogra- phy–instrumental neutron activation analysis (NAA) combinations were used. The remarkable accumulator Sarcosphaera coronaria (up to 2000 mg As kg−1 dry wt) contained only methylarsonic acid, Entoloma lividum only arsenite and arsenate. In Laccaria amethystina dimethylarsinic acid was the major arsenic compound. Sarcodon imbricatum and the two Agaricus sp. were found to contain arsenobetaine as the major arsenic species, a form which had previously been found only in marine biota. Its identification was confirmed by electron impact MS.
TL;DR: The plant-induced processes in wetland soils may not only affect the availability of zine and arsenic to plantsmore but also may play an important role in the sink function of wetlands for metals and metalloids.
Abstract: Oxidation of the rhizosphere by wetland plants leads to precipitation of iron oxyhydroxides (ironplaque) in the rhizosphere and on the root surface of the plants. Arsenic and zinc have a high binding affinity for iron oxyhydroxides and were found to accumulate in ironplaque on roots of Aster tripolium L. It was argued that rhizosphere oxidation and formation of an ironplaque would favor the accumulation of iron, arsenic and zinc in the rhizosphere. Oxidation of ferrous iron to its ferric form would lead to precipitation of iron oxyhydroxides in the rhizosphere, which in turn would lead to a decreasing concentration gradient of dissolved iron towards the plant roots. The iron oxyhydroxides in turn would bind arsenic and zinc, again creating a decreasing concentration gradient of both elements towards the roots. These gradients would lead to the diffusion of iron, arsenic and zinc in the direction of the roots. Assuming that uptake of the elements by the roots is slower than supply through diffusion, an increase in concentrations of all three elements would be expected to occur in the solid phase of the rhizosphere. The plant-induced processes in wetland soils may not only affect the availability of zine and arsenic to plantsmore » but also may play an important role in the sink function of wetlands for metals and metalloids. This paper reports the results of a pilot field study which compared concentrations of the metals in ironplaque, rhizosphere soil and bulk soil under Spartina anglica and Halimione portulacoides. 20 refs., 3 figs., 2 tabs.« less
01 Dec 1995
TL;DR: Arsenic is a very important contaminant of drinking water and other substances and represents approximately half of the estimated carcinogenic potential in coal fly ash as discussed by the authors, however, it is difficult to assess the impact of arsenic contamination on a wide variety of areas including distribution, regulation, safety, physiology and medicine.
Abstract: Arsenic is a very important contaminant of drinking water and other substances. It represents approximately half of the estimated carcinogenic potential in coal fly ash. This important new work is written by top international experts in the field who assess the impact of arsenic contamination on a wide variety of areas including distribution, regulation, safety, physiology and medicine. Attention is focused on arsenic in drinking water.
TL;DR: In this paper, the authors measured sediment traps from two cores from the Kalix River estuary and concluded that the interpretation of sedimentary arsenic profiles may be severely complicated due to post-depositional migration of arsenic.
TL;DR: Evidence is presented to suggest that As(III) also formed mixed complexes with protein and glutathione, possibly ProS-As-(SG)x, and the main pathway for arsenate reduction in red cells is sulfhydryl dependent.
Abstract: Arsenic-thiol interactions were investigated by determining changes in rat blood sulfhydryls after exposure to arsenate, As(V), or arsenite, As(III). Incubation with As(V) resulted in time- and dose-dependent depletion of nonprotein sulfhydryls (NPSH), specifically glutathione (GSH). At the highest As(V) concentration (10 mM), significant loss of glutathione was only observed after 3 h of incubation, but by 5 h 0.5 mM As(V) and higher was sufficient to deplete GSH. As(V) was reduced to As(III) at all dose levels, indicating a redox interaction with GSH, but oxidized glutathione (GSSG) was not formed in sufficient quantities to account for losses in GSH. This may be due to formation of another oxidized species such as a protein-mixed-disulfide (ProSSG). Further evidence that glutathione reduces arsenate was obtained by pretreating cells with the sulfhydryl derivatizing agent N-ethylmaleimide (NEM). Removal of thiols with NEM severely inhibited the formation of As(III) in these incubations, indicating that the main pathway for arsenate reduction in red cells is sulfhydryl dependent. As(III) demonstrated a completely different profile of sulfhydryl interaction. Sulfhydryls (NPSH and GSH) were depleted but the losses were primarily accounted for by oxidation to GSSG. As(III) was also a more potent sulfhydryl depleting agent, requiring only 0.1 mM As(III) to significantly reduce GSH after 5 h of incubation. Significant levels of GSSG formed at all doses of As(III). Evidence is presented to suggest that As(III) also formed mixed complexes with protein and glutathione. Samples that were acid precipitated displayed loss of cytosolic glutathione, which could be reversed if NEM was added prior to protein precipitation. Arsenic was detected in high quantities in the protein precipitates, and this was also found to be reversible by NEM treatment. The fact that both GSH depletion and protein binding were reversible by NEM treatment points to formation of a mixed complex of protein, GSH, and As(III), possibly ProS-As-(SG)x. Arsenic affinity chromatography and polyacrylamide gel electrophoresis were used to characterize arsenic binding proteins in red-cell cytosol. The main arsenic binding protein appeared to be hemoglobin.
TL;DR: In this paper, an industrial waste containing large amounts of arsenic (42 wt %) was studied, and the waste was treated using solidification/stabilisation technology (S S ) with cement and pozzolanic materials.
TL;DR: It is proposed that most of the variation in total arsenic concentrations in the Waikato River are likely to follow a regular seasonal variation, being about 10-25 microg litre(-1) higher in the summer months.
TL;DR: In this article, the authors reviewed the findings on methylation of tin, mercury, and arsenic in the environment, and the development of separation and detection systems in trace analysis has made it possible to determine the concentration of these methylated forms in the environments.
Abstract: Findings on methylation of tin, mercury, and arsenic in the environment are reviewed. The development of separation and detection systems in trace analysis has made it possible to determine the concentration of these methylated forms in the environment. Abiological methylation mechanisms are similar for these three metals, and methylcobalamin and methyl iodide are thought to be the major methyl donors in the environment. Photochemical reaction and transalkylation produce methylmetals. Humic and fulvic acids are the factors affecting methylation. The research on biological methylation started from incubation with polluted water and sediments, and some exceptional reports cast doubt as to whether it was really biomethylation. Some organisms that can form methyl metals from their metal forms have been separated, and the mechanism has been investigated using the pure culture. Methylation of tin and mercury increases the toxicity of their original metal forms, while methylation of arsenic lowers its t...
TL;DR: Soil collected from a disused cattle dip in northern New South Wales was studied with the aim of developing an inexpensive, yet effective method for quantitative determination of arsenic(III), arsenic(V) and total organic arsenic in a contaminated soil.
TL;DR: In this article, an industrial waste, originating from a metallurgical process in which copper is refined and containing large amounts of arsenic (42 wt%), was studied, and a suitable treatment method, solidification/stabilisation (SS), allowing a reduction of the leachability of arsenic from the waste was studied and optimised by measurement of the influence of all additives used in the process.
TL;DR: In this article, a study was made of thiourea as an agent for the pre-reduction and masking of interferences in the multi-element determination of arsenic, antimony, bismuth, selenium and tellurium by hydride generation inductively coupled plasma atomic emission spectrometry.
Abstract: A study was made of thiourea as an agent for the pre-reduction and masking of interferences in the multi-element determination of arsenic, antimony, bismuth, selenium and tellurium by hydride generation inductively coupled plasma atomic emission spectrometry. Thiourea reduces arsenic and antimony from the pentavalent to the trivalent state, without preventing the determination of tetravalent selenium and tellurium. Thiourea also eliminates the interference from a number of metals in the determination of arsenic, antimony and bismuth, but it is not effective for selenium and tellurium.
TL;DR: In this paper, the analytical potential of such a hybrid technique is illustrated for the speciation of mercury and arsenic compounds using a combination of vesicle-mediated high-performance liquid chromatography (HPLC) and microwave-induced plasma (MIP) detection.
Abstract: The on-line coupling of vesicle-mediated high-performance liquid chromatography (HPLC) to low-power argon microwave-induced plasma (MIP) detection is described. The analytical potential of such a hybrid technique is illustrated for the speciation of mercury and arsenic compounds. Continuous cold vapour (CV) or hydride generation (HG) techniques were used as interfaces between the exit of the HPLC column and the MIP, held in a surfatron at reduced pressure. Detection was by atomic emission spectrometry (AES). The effect of different surfactants on mercury CV generation was evaluated using SnCl2 as the reducing solution instead of sodium tetrahydroborate(III). Emission signals increased by about 75% by adding the vesicle-forming surfactant didodecyldimethylammonium bromide (employed as the HPLC mobile phase for speciation). Enhancements of around 100% of signals were found in micelles of cetyltrimethylammmonium bromide. The detection limits by vesicular HPLC–HG-MIP-AES for the more toxic arsenic species investigated (namely, arseneous, arsenic, monomethylarsonic and dimethylarsinic acids) were in the range 1–6 ng ml–1. The detection limits for mercury speciation by vesicular HPLC–CV-MIP-AES were 0.15 ng ml–1 Hg for inorganic mercury and 0.35 ng ml–1 Hg for methylmercury. Both methods have been successfully applied to the speciation of mercury and arsenic in natural waters (sea-water and tap water) and in human urine.
TL;DR: In this paper, blue mussels (Mytilus edulis) were exposed to 100 μg As dm -3 in the form of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide or dimethyl(2-hydroxyethyl)arsine oxoxide in seawater for 10 days.
Abstract: Blue mussels (Mytilus edulis) were exposed to 100 μg As dm -3 in the form of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide or dimethyl(2-hydroxyethyl)arsine oxide in seawater for 10 days. The seawater was renewed and spiked with the arsenic compounds daily. Analyses of water samples taken 24 h after spiking showed that arsenobetaine and arsenocholine had been converted to trimethylarsine oxide, whereas trimethylarsine oxide and tetramethylarsonium iodide were unchanged. Arsenobetaine was accumulated by mussels most efficiently, followed in efficiency by arsenocholine and tetramethylarsonium iodide. None of the other arsenic compounds was significantly accumulated by the mussels. Extraction of mussel tissues with methanol revealed that control mussels contained arsenobetaine, a dimethyl-(5-ribosyl)arsine oxide and an additional arsenic compound, possibly dimethylarsinic acid. Mussels exposed to arsenobetaine contained almost all their experimentally accumulated arsenic as arsenobetaine, and mussels exposed to tetramethylarsonium iodide contained it as the tetramethylarsonium compound. Mussels exposed to arsenocholine had arsenobetaine as the major arsenic compound and glycerylphosphorylarsenocholine as a minor arsenic compound in their tissues. The results show that arsenobetaine and arsenocholine are efficiently accumulated from seawater by blue mussels and that in both cases the accumulated arsenic is present in the tissues as arsenobetaine. Consequently arsenobetaine and/ or arsenocholine present at very low concentrations in seawater may be responsible for the presence of arsenobetaine in M. edulis and probably also among other marine animals. The quantity of arsenobetaine accumulated by the mussels decreases with increasing concentrations of betaine. HPLC-ICP-MS was found to be very powerful for the investigation of the metabolism of arsenic compounds in biological systems.
TL;DR: The arsenic species which can be measured using the hydride procedure may represent intermediates in the decomposition of the bioarsenicals, such as arsenosugars, which are released, either actively as excretion/secretion products or passively as part of the decay process.
Abstract: The links between dissolved arsenic speciation, biological activity and the availabilities of the nitrogen and phosphorus plant nutrients have been investigated in a seasonal survey of Southampton Water (U.K.). Southampton Water (Hampshire, southern England) is an approximately 10 km long, and 2 km wide north-westerly extension of the Solent, receiving water from the rivers Test and Itchen. It is a partially mixed estuary bordered by broad intertidal mudflats with shingle and sand on the eastern side, and a salt marsh to the west. Two sites were chosen: NW Netley Buoy is in a sheltered high-salinity estuarine environment whilst Calshot Buoy lies just outside Southampton Water and in a more exposed location of less-variable salinity. The first evidence of arsenic(III) production at both sites occurred in the second half of April, during the decay of a major Skeletonema costatum diatom bloom. Arsenic(III) levels rose as Skeletonema was replaced by a numerically smaller but more chlorophyll-rich bloom of another diatom, Rhizosolenia delicatula. Rhizosolenia is therefore implicated as a possible source of arsenic(III). Methylated arsenic was absent whilst the water temperature was low and during the initial Skeletonema bloom, but a week later, during the growth phase of the succeeding bloom of the diatom R. delicatula , they became detectable. Methylated arsenic levels gradually increased through the spring to a broad maximum covering the mid-summer, when Mesodinium rubrum , Scrippsiella trochoidea and associated microflagellates also peaked. No subsequent single organism could be linked to the release of methylated arsenic into Southampton Water; organoarsenicals having been observed in the presence of flagellates, diatoms and ciliates. A large bacterial maximum was observed following blooms of S. trochoidea and M. rubrum but laboratory culture experiments of natural bacteria from Netley failed to produce significant changes in the concentration of any arsenic species. Phosphate depletion did not appear to be a prerequisite for arsenate assimilation. From the summer peak methylated arsenic levels then gradually diminished to undetectable levels in the winter months. Monomethylarsenic, present at concentrations approximately 50% those of dimethylarsenic, persisted longer through the summer. The arsenic species which can be measured using the hydride procedure may therefore represent intermediates in the decomposition of the bioarsenicals, such as arsenosugars, which are released, either actively as excretion/secretion products or passively as part of the decay process. Currently unidentified precursors of hydride-reducible arsenic species (‘ hidden ’ arsenic) may explain the poor link between planktonic activity and the levels of measurable arsenic species in the water column.
TL;DR: Using directly coupled ion-pair, reversed phase, high-performance liquid chromatography and inductively coupled plasma mass spectrometry, arsenic acid (AsV) was identified as a major arsenic species in spring-waters and bottled mineral waters.
Abstract: Using directly coupled ion-pair, reversed-phase, high-performance liquid chromatography and inductively coupled plasma mass spectrometry, arsenic acid (AsV) was identified as a major arsenic species in spring-waters and bottled mineral waters. Spring-waters were collected from a volcanic area in the centre of France and bottled waters were purchased from local supermarkets. Two bottled waters also contained traces of arsenious acid (AsIII); no monomethylarsonic acid (MMA) or dimethylarsinic acid (DMA) were characterized in the samples. Using this developed method, six arsenic species were determined with limits of detection sufficiently low to study the chemical species at their naturally occurring concentration levels. Detection limits were in the range of 1.0–3.0 µg l–1 and a good mass balance was obtained with total As content in samples determined by a hydride generation system.
TL;DR: Anion and cation exchange HPLC-ICP-MS was used to separate and detect mixtures of four dimethylarsinyl-riboside derivatives (arsenosugars), in the presence of eight other arsenic species naturally occurring in the marine environment as mentioned in this paper.
Abstract: Anion and cation exchange HPLC-ICP-MS was used to separate and detect mixtures of four dimethylarsinyl-riboside derivatives (arsenosugars), in the presence of eight other arsenic species naturally occurring in the marine environment. The separations achieved showed that two arsenosugars 11 and 13 (cf. Table 2) were present in shellfish certified reference materials (CRMs) and in a lobster hepatopancreas CRM. The concentration of the two arsenosugars in the shellfish samples amounts to 18% of the total arsenic as compared to arsenobetaine at 9–13% and dimethylarsinate at 4–9% of the total arsenic. Additionally, a chromatographic peak with the same retention time as that of 2-dimethylarsinylacetic acid was detected in the shellfish samples. Further support of the identity of this peak was gained after spiking the sample extracts with the standard substance which resulted in a single, but larger peak. The indication that this novel arsenical is present in shellfish, and the recently reported finding of arsenocholine in seafood supports a proposed marine biosynthetic pathway of arsenic that includes both of these compounds as the immediate precursors of arsenobetaine, the end-product of the marine arsenic metabolism.