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1. Determination of Total Arsenic and Speciation in Apple Juice by Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry: An Experiment for the Analytical Chemistry Laboratory

   https://doi.org/10.1021/acs.jchemed.6b00076  

   He, Ping ; Colón, Luis A. ; Aga, Diana S. ( October 2016 , Journal of Chemical Education)
2. Inhibition of methanogenesis leads to accumulation of methylated arsenic species and enhances arsenic volatilization from rice paddy soil

   https://doi.org/10.1016/j.scitotenv.2021.151696  

   Zhang, Xuhui ; Reid, Matthew C. ( April 2022 , Science of The Total Environment)
3. High Arsenic Levels Increase Activity Rather than Diversity or Abundance of Arsenic Metabolism Genes in Paddy Soils

   https://doi.org/10.1128/AEM.01383-21  

   Zhang, Si-Yu ; Xiao, Xiao ; Chen, Song-Can ; Zhu, Yong-Guan ; Sun, Guo-Xin ; Konstantinidis, Konstantinos T. ( September 2021 , Applied and Environmental Microbiology)

   Cann, Isaac (Ed.)

   ABSTRACT Arsenic (As) metabolism genes are generally present in soils, but their diversity, relative abundance, and transcriptional activity in response to different As concentrations remain unclear, limiting our understanding of the microbial activities that control the fate of an important environmental pollutant. To address this issue, we applied metagenomics and metatranscriptomics to paddy soils showing a gradient of As concentrations to investigate As resistance genes ( ars ) including arsR , acr3 , arsB , arsC , arsM , arsI , arsP , and arsH as well as energy-generating As respiratory oxidation ( aioA ) and reduction ( arrA ) genes. Somewhat unexpectedly, the relative DNA abundances and diversities of ars , aioA , and arrA genes were not significantly different between low and high (∼10 versus ∼100 mg kg −1 ) As soils. Compared to available metagenomes from other soils, geographic distance rather than As levels drove the different compositions of microbial communities. Arsenic significantly increased ars gene abundance only when its concentration was higher than 410 mg kg −1 . In contrast, metatranscriptomics revealed that relative to low-As soils, high-As soils showed a significant increase in transcription of ars and aioA genes, which are induced by arsenite, the dominant As species in paddy soils, but not arrA genes, which are induced by arsenate. These patterns appeared to be community wide as opposed to taxon specific. Collectively, our findings advance understanding of how microbes respond to high As levels and the diversity of As metabolism genes in paddy soils and indicated that future studies of As metabolism in soil or other environments should include the function (transcriptome) level. IMPORTANCE Arsenic (As) is a toxic metalloid pervasively present in the environment. Microorganisms have evolved the capacity to metabolize As, and As metabolism genes are ubiquitously present in the environment even in the absence of high concentrations of As. However, these previous studies were carried out at the DNA level; thus, the activity of the As metabolism genes detected remains essentially speculative. Here, we show that the high As levels in paddy soils increased the transcriptional activity rather than the relative DNA abundance and diversity of As metabolism genes. These findings advance our understanding of how microbes respond to and cope with high As levels and have implications for better monitoring and managing an important toxic metalloid in agricultural soils and possibly other ecosystems. 

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4. Bioremediation of arsenic-contaminated groundwater by sequestration of arsenic in biogenic pyrite

   https://doi.org/10.1016/j.apgeochem.2018.07.007  

   Saunders, James A. ; Lee, Ming-Kuo ; Dhakal, Prakash ; Ghandehari, Shahrzad Saffari ; Wilson, Ted ; Billor, M. Zeki ; Uddin, Ashraf ( September 2018 , Applied Geochemistry)
5. Raman and Electrical Transport Properties of Few-Layered Arsenic-Doped Black Phosphorus

   https://doi.org/10.1039/C9NR04598H  

   Pradhan, Nihar Ranjan ; Garcia, Carlos ; Lucking, Michael ; Pakhira, Sriamanta ; Martinez, Juan ; Rosenmann, Daniel ; Divan, Ralu ; Sumant, Anirudha ; Terrones, H. ; Mendoza-Cortes, Jose L. ; et al ( January 2019 , Nanoscale)

   Black phosphorus (b-P) is an allotrope of phosphorus whose properties have attracted great attention. In contrast to other 2D compounds, or pristine b-P, the properties of b-P alloys have yet to be explored. In this report, we present a detailed study on the Raman spectra and on the temperature dependence of the electrical transport properties of As-doped black phosphorus (b-AsP) for an As fraction x = 0.25. The observed complex Raman spectra were interpreted with the support of Density Functional Theory (DFT) calculations since each original mode splits in three due to P-P, P-As, and As-As bonds. Field-effect transistors (FET) fabricated from few-layered b-AsP exfoliated onto Si/SiO 2 substrates exhibit hole-doped like conduction with a room temperature ON/OFF current ratio of ~10 3 and an intrinsic field-effect mobility approaching ~300 cm 2 /Vs at 300 K which increases up to 600 cm 2 /Vs at 100 K when measured via a 4-terminal method. Remarkably, these values are comparable to, or higher, than those initially reported for pristine b-P, indicating that this level of As doping is not detrimental to its transport properties. The ON to OFF current ratio is observed to increase up to 10 5 at 4 K. At high gate voltages b-AsP displays metallic behavior with the resistivity decreasing with decreasing temperature and saturating below T ∼ 100 K, indicating a gate-induced insulator to metal transition. Similarly to pristine b-P, its transport properties reveal a high anisotropy between armchair (AC) and zig-zag (ZZ) directions. Electronic band structure computed through periodic dispersion-corrected hybrid Density Functional Theory (DFT) indicate close proximity between the Fermi level and the top of the valence band(s) thus explaining its hole doped character. Our study shows that b-AsP has potential for optoelectronics applications that benefit from its anisotropic character and the ability to tune its band gap as a function of the number of layers and As content. 

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