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Metal nanomaterials, such as silver and copper, are often incorporated into commercial textiles to take advantage of their Antibacterial and antiviral properties. The goal of this study was to identify the most parsimonious method for the synthesis of silver, copper, or silver/copper bimetallic treated textiles. To accomplish this eight different methods were employed to synthesize silver, copper, and silver/copper functionalized cotton batting textiles. Using silver and copper nitrate as precursors, different reagents were used to initiate/catalyze the deposition of metal, including: (1) no additive, (2) sodium bicarbonate, (3) green tea, (4) sodium hydroxide, (5) ammonia, (6, 7) sodium hydroxide/ammonia at a 1:2 and 1:4 ratio, and (8) sodium borohydride. The use of sodium bicarbonate as a reagent to reduce silver onto cotton has not been used previously in literature and was compared to established methods. All synthesis methods were performed at 80 °C for one hour following textile addition to the solutions. The products were characterized by x-ray fluorescence (XRF) analysis for quantitative determination of the metal content and x-ray absorption near edge structure (XANES) analysis for silver and copper speciation on the textile. Scanning electron microscopy (SEM) with energy dispersive x-ray (EDX) and size distribution inductively coupled plasma mass spectrometry (ICP-MS) were used to further characterize the products of the sodium bicarbonate, sodium hydroxide, and sodium borohydride synthesis methods following ashing of the textile. For the silver treatment methods (1 mM Ag +), sodium bicarbonate and sodium hydroxide resulted in the highest amounts of silver on the textile (8900 mg Ag/kg textile and 7600 mg Ag/kg textile) and for copper treatment (1 mM Cu +) the sodium hydroxide and sodium hydroxide/ammonium hydroxide resulted in the highest amounts of copper on the textile (3800 mg Ag/kg textile and 2500 mg Ag/kg textile). Formation of copper oxide was dependent on the pH of the solution, with 4 mM ammonia and other high pH solutions resulting in majority of the copper on the textile existing as copper oxide, with smaller amounts of ionic-bound copper. The identified parsimonious methods will lend themselves to the efficient manufacturing of antibacterial and antiviral textiles, or the development of multifunctionalized smart textiles. [ABSTRACT FROM AUTHOR]

Uptake, distribution and speciation of arsenic (As) were determined in the bracket fungus Fomitopsis betulina (previously Piptoporus betulinus), commonly known as the birch polypore, collected from a woodland adjacent to a highly contaminated former mine in the Southwest UK and at an uncontaminated site in Quebec, Canada, with no past or present mining activity. The fruiting body was divided into cap, centre and pores representing the top, middle and underside to identify trends in the distribution and transformation of As. Total As, determined by inductively coupled plasma–mass spectrometry (ICP–MS), was approximately tenfold higher in the mushroom from the contaminated compared to the uncontaminated site. Overall, accumulation of As was low relative to values reported for some soil-dwelling species, with maximum levels of 1.6 mg/kg at the contaminated site. Arsenic speciation was performed on aqueous extracts via both anion and cation high-performance liquid chromatography–ICP–MS (HPLC–ICP–MS) and on whole dried samples using X-ray absorption near edge structure (XANES) analysis. Seven As species were detected in F. betulina from the contaminated site by HPLC–ICP–MS: arsenite (AsIII), arsenate (AsV), dimethylarsinate (DMAV), methylarsonate (MAV), trimethylarsine oxide (TMAO), tetramethylarsonium ion (Tetra) and trace levels of arsenobetaine (AB). The same As species were observed at the uncontaminated site with the exception of TMAO and Tetra. Arsenic species were localized throughout the fruiting body at the contaminated site, with the cap and pores containing a majority of AsV, only the cap containing TMAO, and the pores containing higher concentrations of DMAV and MAV as well as tetra and a trace of AB. XANES analysis demonstrated that the predominant form of As at the contaminated site was inorganic AsIII coordinated with sulphur or oxygen and AsV coordinated with oxygen. This is the first account of arsenic speciation in F. betulina or any fungi of the family Fomitopsidaceae. [ABSTRACT FROM AUTHOR]

Biochar is a renewable energy byproduct that shows promise for remediating contaminated mine sites. A common contaminant at mine sites is arsenic (As). In this study, the effects of biochar amendments to a mine-contaminated soil on As concentrations in mountain brome (Bromus marginatus Nees ex Steud.) were investigated. In the biochar-amended soil, mountain brome had greater root biomass and decreased root and shoot As concentrations. X-ray absorption near-edge structure spectroscopy results showed that arsenate [As(V)] is the predominant species in both the nonamended and biochar-amended soils. Soil extraction tests that measure phosphate and arsenate availability to plants failed to accurately predict plant tissue As concentrations, suggesting the arsenate bioavailability behavior in the soils is distinct from phosphate. Results from this study indicate that biochar will be a beneficial amendment to As-contaminated mine sites for remediation. [ABSTRACT FROM AUTHOR]

Abstract: Arsenic and lead have been found in a number of traditional Ayurvedic medicines, and the practice of Rasa Shastra (combining herbs with metals, minerals and gems), or plant ingredients that contain these elements, may be possible sources. To obtain an estimate of arsenic and lead solubility in the human gastrointestinal tract, bioaccessibility of the two elements was measured in 42 medicines, using a physiologically-based extraction test. The test consisted of a gastric phase at pH 1.8 containing organic acids, pepsin and salt, followed by an intestinal phase, at pH 7 and containing bile and pancreatin. Arsenic speciation was measured in a subset of samples that had sufficiently high arsenic concentrations for the X-ray absorption near edge structure analysis used. Bioaccessible lead was found in 76% of samples, with a large range of bioaccessibility results, but only 29% of samples had bioaccessible arsenic. Lead bioaccessibility was high (close to 100%) in a medicine (Mahayograj Guggulu) that had been compounded with bhasmas (calcined minerals), including naga (lead) bhasma. For the samples in which arsenic speciation was measured, bioaccessible arsenic was correlated with the sum of As(V)–O and As(III)–O and negatively correlated with As–S. These results suggest that the bioaccessible species in the samples had been oxidized from assumed As–S raw medicinal ingredients (realgar, As4S4, added to naga (lead) bhasma and As(III)–S species in plants). Consumption at recommended doses of all medicines with bioaccessibile lead or arsenic would lead to the exceedance of at least one standard for acceptable daily intake of toxic elements. [Copyright &y& Elsevier]

Abstract: The localization and identification of arsenic compounds in terrestrial plants are important for the understanding of arsenic uptake, transformation and translocation within these organisms, and contributes to our understanding of arsenic cycling in the environment. High performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS), and X-ray absorption near-edge structure (XANES) analysis identified arsenite, arsenate and arsenic(III)–sulphur compounds in leaf, stem and root sections of Rhaphanus sativus (radish) plants grown in both arsenic contaminated mine waste, and arsenic amended liquid cultures. The total arsenic distribution was similar between the plants grown in mine waste and those grown hydroponically. Arsenate was the predominant form of arsenic available in the growth mediums, and after it was taken up by roots, X-ray absorption spectroscopy (XAS) imaging indicated that some of the arsenate was transported to the shoots via the xylem. Additionally, arsenate was reduced by the plant and arsenic(III)–sulphur compound(s) accounted for the majority of arsenic in the leaf and stem of living plants. In this study the application of synchrotron techniques permitted the identification of arsenic(III)–sulphur species which were “invisible” to conventional HPLC-ICP-MS analysis. [Copyright &y& Elsevier]

Arsenic is an element that is ubiquitous in the environment and is known to form compounds with toxic, even carcinogenic properties. Arsenic toxicity is a function of its chemical form (species). Identification of arsenic species is necessary to accurately determine the transformation and fate of arsenicals as well as the actual risk posed by arsenic contamination. We report X-ray absorption near-edge structure (XANES) measurements of 16 biologically important arsenic compounds. Solid and aqueous standards were studied for differences in XANES spectral features, white line positions, stability during exposure to the beam, and stability between two beam exposures separated by 48 h. Samples containing As(III) (11870.0-118713 ± 0.5 eV) and As(V) (11872.6-11875.3 ± 0.5 eV) were easily distinguished by white line energies and could be further subdivided into a total of seven groups. Valuable examples include As(III)--sulfur compounds (11870.0 ± 0.5 eV), arsenobetaine and arsenocholine (11812.6 ± 0.5 eV), and a dimethyl arsinyl riboside (11813.3 ± 0.5 eV). A growing number of environmental and biological studies use X-ray absorption spectroscopy (XAS) results to complement their more traditional analyses. Results provided here are intended to help make XAS more accessible to new users interested in the study of arsenic in the environment. [ABSTRACT FROM AUTHOR]

Using XANES, we studied the recently identified hexa-coordinated pentavalent arsenic, specifically, octahedral As(v)-glycerol compound As(v)(OCH2CH(O)CH2OH)3. It is stable at all pHs tested (1–12), but is transformed to the conventional tetrahedral AsO43− compound in the presence of water. Dehydration of environmental samples (i.e., Manitoba maple leaf and hare muscle) spiked with a AsO43− standard resulted in XANES features of the As(v)-glycerol compound. Therefore the compound we hypothesize to be the As(v)-glycerol in environmental samples is likely only visible using XAS analysis, and does not appear to survive wet environments such as those in biological systems, where toxicity may be experienced, or in conventional speciation methods, which generally use aqueous separation techniques. [ABSTRACT FROM AUTHOR]

Abstract: A sequential arsenic extraction method was developed that yielded extraction efficiencies (EE) that were approximately double those using current methods for terrestrial plants. The method was applied to plants from two arsenic contaminated sites and showed potential for risk assessment studies. In the method, plants were extracted first by 1:1 water–methanol followed by 0.1M hydrochloric (HCl) acid. Total arsenic in plant and soil samples collected from contaminated sites was mineralized by acid digestion and detected by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and hydride generation-atomic absorption spectrometry (HG-AAS). Arsenic speciation was done by high performance liquid chromatography coupled with HG-AAS (HPLC–HGAAS) and by HPLC coupled with ICP-mass spectrometry (HPLC–ICP-MS). Spike recovery experiments with arsenite (As(III)), arsenate (As(V)), methylarsonic acid (MA) and dimethylarsinic acid (DMA) showed stability of the species in the extraction processes. Speciation analysis by X-ray absorption near edge spectroscopy (XANES) demonstrated that no transformation of As(III) and As(V) occurred due to sample handling. Dilute HCl was efficient in extracting arsenic from plants; however, extraction and determination of organic species were difficult in this medium. Sequential extraction with 1:1 water–methanol followed by 0.1M-HCl was most useful in extracting and speciating both organic and inorganic arsenic from plants. Trace amounts of MA and DMA in plants could be detected by HPLC–HGAAS aided by the process of separation and preconcentration of the sequential extraction method. Both organic and inorganic arsenic compounds could be detected simultaneously in synthetic gastric fluid extracts (GFE) but EEs by this method were lower than those of the sequential method. The developed sequential method was shown to be reliable and applicable to various terrestrial plants for arsenic extraction and speciation. [Copyright &y& Elsevier]

Bioaccessibility tests and mineralogical analyses were performed on arsenic-contaminated tailings and soils from gold mine districts of Nova Scotia, Canada, to examine the links between soil composition, mineralogy, and arsenic bioaccessibility. Arsenic bioaccessibility ranges from 0.1% to 49%. A weak correlation was observed between total and bioaccessible arsenic concentrations, and the arsenic bioaccessibility was not correlated with other elements. Bulk X-ray absorption near-edge structure analysis shows arsenic in these near-surface samples is mainly in the pentavalent form, indicating that most of the arsenopyrite (As1-) originally present in the tailings and soils has been oxidized during weathering reactions. Detailed mineralogical analyses of individual samples have identified up to seven arsenic species, the relative proportions of which appear to affect arsenic bioaccessibility. The highest arsenic bioaccessibility (up to 49%) is associated with the presence of calcium-iron arsenate. Samples containing arsenic predominantly as arsenopyrite or scorodite have the lowest bioaccessibility (<1%). Other arsenic species identified (predominantly amorphous iron arsenates and arsenic-bearing iron(oxy)hydroxides) are associated with intermediate bioaccessibility (1 to 10%). The presence of a more soluble arsenic phase, even at low concentrations, results in increased arsenic bioaccessibility from the mixed arsenic phases associated with tailings and mine-impacted soils. [ABSTRACT FROM AUTHOR]