ArticleLiterature Review

Toxicity of indium arsenide, gallium arsenide, and aluminium gallium arsenide

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Abstract

Gallium arsenide (GaAs), indium arsenide (InAs), and aluminium gallium arsenide (AlGaAs) are semiconductor applications. Although the increased use of these materials has raised concerns about occupational exposure to them, there is little information regarding the adverse health effects to workers arising from exposure to these particles. However, available data indicate these semiconductor materials can be toxic in animals. Although acute and chronic toxicity of the lung, reproductive organs, and kidney are associated with exposure to these semiconductor materials, in particular, chronic toxicity should pay much attention owing to low solubility of these materials. Between InAs, GaAs, and AlGaAs, InAs was the most toxic material to the lung followed by GaAs and AlGaAs when given intratracheally. This was probably due to difference in the toxicity of the counter-element of arsenic in semiconductor materials, such as indium, gallium, or aluminium, and not arsenic itself. It appeared that indium, gallium, or aluminium was toxic when released from the particles, though the physical character of the particles also contributes to toxic effect. Although there is no evidence of the carcinogenicity of InAs or AlGaAs, GaAs and InP, which are semiconductor materials, showed the clear evidence of carcinogenic potential. It is necessary to pay much greater attention to the human exposure of semiconductor materials.

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... The main application of gallium is the production of semiconducting compounds. Gallium arsenide is the most widely used compound among galliumcontaining semiconductors [1][2][3][4]. The increasing use of gallium arsenide has posed the question concerning its toxicity [3]. ...
... The increasing use of gallium arsenide has posed the question concerning its toxicity [3]. The available data indicate that it can be toxic in animals and humans [4,5]. The other application of gallium is as a component of medicinal inorganic therapeutic and diagnostic agents [6]. ...
... However, only a few electrodes have been developed for Ga(III) ion determination. Some characteristics of the electrodes and developed techniques are presented in Table 3. 4-(p-nitrophenyl azo)-pyrocatechol -PVC -tributylpho-sphate 3.5 5·10 -6 -8.3·10 -5 4·10 -6 600-900 - [61] multi-walled carbon nanotube PVC based on 7-(2-hydroxy-5-methoxybenzyl)-5,6,7,8,9,10hexahydro-2H benzo [b] [1,4,7,10,13] dioxa triaza cyclopentadecine-3,11(4H,12H)-dione ionophore + dibutyl sebacate 2.4-6.0 7.9·10 -7 -3.2·10 -2 3.2·10 -7 10-16 40 [58] aliquat 336 -PVC -1.0·10 -4 -1. ...
... One of the key elements in the development of the proposed photonic biosensor to monitor growth and antibiotic susceptibility of bacteria is investigation of growth of bacteria on the surface of GaAs, our material of interest for capping GaAs/AlGaAs heterostructures. Due to the toxic properties of arsenic (As) and gallium (Ga) (Tanaka 2004), we should find the minimum bacterial concentration that could grow on GaAs surfaces while the biochips are kept in darkness or irradiated under laser light. ...
... For bacterial concentrations lower than 2×10 8 CFU/mL, for which around 800-900 bacteria/mm 2 were observed immobilized on the biochip surface (see Supporting Information), we were not able to monitor bacterial growth. The likely reason for this behaviour is a poisonous effect of As and Ga ions released by the photocorroding biochip to the flow cell, which could affect the viability of bacteria (Harvey and Crundwell 1996;Podol'skaia et al. 2002;Tanaka 2004). We note that a non-irradiated GaAs substrate could support the growth of E. coli K12 at concentrations as low as 10 5 CFU/mL . ...
... As and the counter-elements of As, such as Ga (Tanaka 2004). However, some bacteria have plasmids carrying arsenic resistance determinants (ars) which make them resistant to arsenic (Paez-Espino et al. 2009). ...
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Monitoring the viability, growth and cellular metabolism of bacteria can contribute significantly to the early diagnosis of disease, but can also help improve yield of bacterial products in industrial- or small-scale experiments. Conventional methods applied for investigation of antibiotic sensitivity of bacteria are mostly culture-based techniques that are time-consuming and take at least 12 h to reveal results. This delay leads to overtreatment of a wide range of infections with broad spectrum antibiotics which is costly and may lead to the development of resistance to these precious antibiotics, whereas rapid detection of a viral infection or absence of bacteria could prevent such treatments and, in the case of bacterial infection, identification of antibiotic susceptibility could allow use of narrow spectrum antibiotics. The project outlined in this document aims at monitoring biological activities of live bacteria immobilized on biofunctionalized surfaces of quantum semiconductor (QS) microstructures. The method takes advantage of the sensitivity of photoluminescence (PL) emitting semiconductors to the perturbation of the electric field induced by the electric charge of bacteria immobilized on the surface of these structures. Our hypothesis was that bacteria growing on the surface of biofunctionalized QS biochips would modify their PL in a different, and measurable way in comparison with inactivated bacteria. In the first phase of the project, we investigated an innovative method involving PL monitoring of the photocorrosion effect in GaAs/AlGaAs heterostructures. Maintaining the balance between device sensitivity and stability in the biosensing (aqueous) environment allowed us to detect Escherichia coli K12 in phosphate buffered saline solutions (PBS) at an attractive limit of detection of 103 CFU/mL in less than 2 hours. Following this research, we hypothesised that these heterostructures could be employed to develop a method for inexpensive and quasi-real time monitoring of the growth and antibiotic susceptibility of bacteria. One of the key elements in the development of this biosensing platform was to demonstrate that GaAs (001), normally used for capping PL emitting GaAs/AlGaAs heterostructures, would not inhibit the growth of bacteria. In the second phase of the project, we explored the capture and growth of E. coli K12 on bare and biofunctionalized surfaces of GaAs (001). It has been determined that the initial coverage, and the subsequent bacterial growth rates are dependent on the biofunctionalization architecture used to capture bacteria, with antibody biofunctionalized surfaces exhibiting significantly higher capture efficiencies. Moreover, for suspensions containing bacteria at less than 105 CFU/mL, it has been found that the surface of GaAs wafers could not support the growth of bacteria, regardless of the type of biofunctionalization architecture. In the third phase of the project, we used PL to monitor the growth and antibiotic susceptibility of E. coli K12 and E. coli HB101 bacteria. While immobilization of bacteria on the surface of GaAs/AlGaAs heterostructures retards the PL monitored photocorrosion, growth of these bacteria further amplifies this effect. By comparing the photocorrosion rate of QS wafers exposed to bacterial solutions with and without antibiotics, the sensitivity of bacteria to the specific antibiotic could be determined in less than 3 hours. Due to the small size, low cost and rapid response of the biosensor, the proposed approach has the potential of being applied in clinical diagnostic laboratories for quick monitoring of antibiotic susceptibility of different bacteria.
... It has been reported to have the potential as a new therapeutic radiopharmaceutical for the treatment of rapidly growing solid tumors [65]. Indium and its compounds have been found to be highly toxic to animals and humans [66,67]. Similar to Al, In compounds have been linked to the induction of oxidative stress [68]. ...
... In medicine, both radioactive ( 67 Ga) and stable isotopes of Ga are applied as diagnostic contrasts [83] and therapeutic agents in various types of cancer as well as some diseases of calcium and bone metabolism. The 67 Ga scan has been used for nearly three decades for tumor detection. The degree of incorporation of the ion inside malignant cells reflects their metabolic activity. ...
Article
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The role metals play in living organisms is well established and subject to extensive research. Some of them participate in electron-exchange reactions. Such reactions cause generation of free radicals that can adversely impact biological systems, as a result of oxidative stress. The impact of ‘non-biological’ metals on oxidative stress is also a worthy pursuit due to the crucial role they play in modern civilization. Lanthanides (Ln) are widely used in modern technology. As a result, human exposure to them is increasing. They have a number of established medical applications and are being extensively researched for their potential antiviral, anticancer and anti-inflammatory properties. The present review focuses on lanthanum (La) and its impact on oxidative stress. Another metal, widely used in modern high-tech is gallium (Ga). In some respects it shows certain similarities to La, therefore it is a subject of the present review as well. Both metals exhibit ionic mimicry which allows them to specifically target malignant cells, initiating apoptosis. That makes their simple salts and coordination complexes promising candidates for future anticancer agents.
... There is increasing evidence to suggest that indium (In) compounds may be harmful to human health, yet the potential transfer mechanisms into the human body are very poorly understood. While in vivo tests on mice and rats have shown that In-phosphide, In-arsenide In-trichloride and In-acetate have toxic and carcinogenic effects (Chapin et al., 1995;Oda, 1997;Tanaka, 2004;Lee et al., 2016), the most widely used compound, indium-tin oxide (ITO), was until recently considered to be comparably inert (Fowler et al., 2009). However, studies by Homma et al. (2003) and Cummings et al. (2010Cummings et al. ( , 2016 linked health problems and fatalities among factory workers to their exposure to ITO. ...
... Sintered ITO remains a hardly soluble compound when compared to other In compounds such as In-phosphide, In-arsenide In-trichloride and In-acetate (Chapin et al., 1995;Oda, 1997;Tanaka, 2004;Lee et al., 2016). Our study demonstrates that ITO is nearly insoluble under simulated upper respiratory tract conditions and in deionized water, while it displays some dissolution in the simulated deep lung and stomach environments. ...
Article
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From being a metal with very limited natural distribution, indium (In) has recently become disseminated throughout the human society. Little is known of how In compounds behave in the natural environment, but recent medical studies link exposure to In compounds to elevated risk of respiratory disorders. Animal tests suggest that exposure may lead to more widespread damage in the body, notably the liver, kidneys and spleen. In this paper, we investigate the solubility of the most widely used In compound, indium-tin oxide (ITO) in simulated lung and gastric fluids in order to better understand the potential pathways for metals to be introduced into the bloodstream. Our results show significant potential for release of In and tin (Sn) in the deep parts of the lungs (artificial lysosomal fluid) and digestive tract, while the solubility in the upper parts of the lungs (the respiratory tract or tracheobronchial tree) is very low.
... Toys [15] carcinogens and very toxic. As, Al, In, and Ga have been shown to be carcinogenic [23][24][25]. Other metallic elements present in e-waste include: beryllium (Be), cobalt (Co), barium (Ba), selenium (Se), zinc (Zn), yttrium (Y), europium (Eu), gold (Au), platinum, iron (Fe), aluminium (Al), tin, germanium, tantalum, vanadium, ruthenium, tanialum, rhodium, americium, palladium, manganese, silver, bismuth, niobium, silica, lithium, tritium, terbium, etc. [23][24][25][26][27][28]. ...
... As, Al, In, and Ga have been shown to be carcinogenic [23][24][25]. Other metallic elements present in e-waste include: beryllium (Be), cobalt (Co), barium (Ba), selenium (Se), zinc (Zn), yttrium (Y), europium (Eu), gold (Au), platinum, iron (Fe), aluminium (Al), tin, germanium, tantalum, vanadium, ruthenium, tanialum, rhodium, americium, palladium, manganese, silver, bismuth, niobium, silica, lithium, tritium, terbium, etc. [23][24][25][26][27][28]. Heavy metals like Pb with known toxicity is present in most electronic devices in large quantities [29]. ...
Article
PurposeIn recent years, electronic waste has become the fastest growing waste stream globally with potential deleterious environmental and public health effects from its hazardous constituents. This review aims at providing an up-to-date information on the environmental and public health effects of e- wastes, and also identify research gaps that could form basis of further innovative studies on this important subject.Methods We carried out literature survey using several search engines. All available literature which reported directly on environmental contamination of air, soil, and water by e-wastes, and their effects on exposed plants, animals, and humans were used in other to generate an updated information.ResultsHigh production volume coupled with indiscriminate disposal and informal recycling has made electronic waste (e-waste) to become a global public and environmental health issue. E-waste is made up of different hazardous substances such as heavy metals and persistent organic pollutants with the capacity to contaminate the environment if processed or recycled inappropriately. Humans and animals become exposed to e-waste constituents via ingestion, inhalation, and dermal contact. Several health effects have been linked to e-wastes. The most susceptible were children, pregnant women, and workers in primitive recycling sites. Generation of e-waste is predicted to increase drastically in the next decade with the potential complex interactive effects of its constituents.Conclusion This review is an up-to-date assessment of studies and reports on e-waste environmental contamination and public health effects. The review has shown that e-waste contains constituents that caused adverse environmental effects and toxicity to the biota. However, there is an enormous data gap between exposure quantification and possible health effects. More studies are needed to elucidate and provide holistic information on environmental and public health dangers posed by e-waste constituents.
... However, chronic exposure to gallium causes toxicity to different organs system, such as the brain, lung, kidney and immune system. It also exerts toxic effects on the transport system and causes different types of cancer [123][124][125]. ...
Article
Thiourea and its derivatives display several electronic and structural features which enable its application in various fields, ranging from biological to non-biological. These compounds contain heteroatom's like sulfur and nitrogen, which are nucleophilic and allow for establishing inter-and intramolecular hydrogen bonding. In addition, they also provide coordination sites to act as ligands in the field of coordination chemistry. Due to these properties, thiourea derivatives are used as chemosensors to detect various metal cations. This article covers a broad range of thiourea based chemosensors that are used for colorimetric and fluorimetric (turn-off and turn-on) detection of different cations such as Ag⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺, Mn²⁺, Cu²⁺, Co²⁺, Al³⁺, Cr³⁺, Ga³⁺, In³⁺, Ru³⁺, and Fe³⁺, etc., in various biological, agricultural and environmental samples. Structural parameters and coordination mechanism of each sensor with metal ions have been discussed. Further, the sensing performances of thioureas derivatives have been compared and discussed, which could help the readers for the future design of highly sensitive and selective organic fluorescent and colorimetric chemosensors to detect metal cations.
... Therefore, we are easily exposed to gallium ions. Gallium ions are known to be carcinogenic and highly noxious to humans and animals [5][6][7]. For example, visual, auditory toxicities and microcytic anemia may materialize in patients medicated with gallium nitrate. ...
Article
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A thiourea-based fluorescent chemosensor NADA, (E)-2-(4-(diethylamino)-2-hydroxybenzylidene)-N-(naphthalen-1-yl)hydrazine-1-carbothioamide, has been designed and synthesized. NADA could detect Ga3+ through a fluorescent turn-on with a low detection limit (0.29 μM). Importantly, NADA could effectively discriminate Ga3+ from Al3+ and In3+. The binding mechanism of NADA with Ga3+ was identified by ESI-mass, NMR titration, and DFT calculations.
... The gate is fabricated from aluminum gallium arsenide (AlGaAs), which has high chemical stability and good electron transport properties. However, toxic effects have been reported for AlGaAs, which makes it unsuitable for medical application with regard to potential direct contact with the patient [142]. ...
Article
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This article reviews existing clinical practices and sensor research undertaken to monitor fetal well-being during labour. Current clinical practices that include fetal heart rate monitoring and fetal scalp blood sampling are shown to be either inadequate or time-consuming. Monitoring of lactate in blood is identified as a potential alternative for intrapartum fetal monitoring due to its ability to distinguish between different types of acidosis. A literature review from a medical and technical perspective is presented to identify the current advancements in the field of lactate sensors for this application. It is concluded that a less invasive and a more continuous monitoring device is required to fulfill the clinical needs of intrapartum fetal monitoring. Potential specifications for such a system are also presented in this paper.
... La contamination des nappes souterraines et superficielles par ces effluents industriels provoque de graves risques pour la santé des populations vivant à proximité des usines et pour l'écosystème. En plus, peu d'études ont été faites sur l'impact de l'Indium sur l'homme et sur l'écotoxicité (Tanaka, 2004). L'objectif de ce travail est d'étudier l'indium comme un modèle des métaux trivalents qui fait partie des métaux stratégiques. ...
Thesis
Les métaux stratégiques, particulièrement les terres rares se trouvent en quantité non négligeable dans l’eau naturelle. L’objectif principal de cette étude étant de connaître la spéciation (distribution chimique) de l’Indium (métal stratégique) et de mieux comprendre le comportement des différentes espèces chimiques de ce métal dans les milieux naturels et leur réactivité en présence des ligands (acide humique). La technique Chronopotentiometryat Scanned deposition Potential (SSCP) a été utilisée pour son avantage de donner accès aux constantes de stabilité et de spéciation dynamique des complexes métalliques. Les paramètres (pH, électrolyte, force ionique et catalyseur) ont été déterminé pour comprendre l’influence de chaque paramètre sur la spéciation de ce métal trivalent modèle (Indium). Une étude primaire sur la complexation d’Indium avec des ligands simples comme l’acide acétique et l’iminodiacétique est réalisée avant d’étudier la complexation d’acide humique qui est compliqué. Après la purification de l’acide humique, nous avons pu déterminer par la technique de titrage potentiométrique la charge de ce ligand. En obtenant par SSCP les constantes de stabilité, l’hétérogénéité chimique, l’influence du pH ou encore du ratio concentration en métal/concentration en acides humiques nous a avons accès à comprendre la complexation de l’indium (In3+) en présence d’acides humiques. Il s’agira d’obtenir un premier set de données sur les interactions entre l’Indium et les acides humiques. Finalement, seul l’Indium comme métal trivalent est compatible par cette technique SCCP et un grand nombre de ligand peut être complexé à l’Indium.
... In addition, only solar cells have been presented as the device application ( , including one groundbreaking solvent-and vacuum-free route to perovskite solar cells, although pressure treatment instead of mechanochemistry was employed ( Chen et al., 2017). Yet, it has been previously proposed that the orthorhombic black CsSnI 3 can be used as a promising alternative to toxic gallium arsenide (GaAs) as a semiconductor material (Tanaka, 2004;Xing et al., 2014). In addition, the cubic CsSnBr 3 has also shown great potential for photodetector applications ( Konstantakou and Stergiopoulos, 2017). ...
Article
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Mechanochemistry is a green, solid-state, re-emerging synthetic technique that can rapidly form complex molecules and materials without exogenous heat or solvent(s). Herein, we report the application of solvent-free mechanochemical ball milling for the synthesis of metal halide perovskites, to overcome problems with solution-based syntheses. We prepared phase-pure, air-sensitive CsSnX3 (X = I, Br, Cl) and its mixed halide perovskites by mechanochemistry for the first time by reactions between cesium and tin(II) halides. Notably, we report the sole examples where metastable, high-temperature phases like cubic CsSnCl3, cubic CsPbI3, and trigonal FAPbI3 were accessible at ambient temperatures and pressures without post-synthetic processing. The perovskites can be prepared up to “kilogram scales.” Lead-free, all-inorganic photodetector devices were fabricated using the mechanosynthesized CsSnBr1.5Cl1.5 under solvent-free conditions and showed 10-fold differences between on-off currents. We highlight an essentially solvent-free, general approach to synthesize metastable compounds and fabricate photodetectors from commercially available precursors. : Devices; Energy Materials; Materials Synthesis Subject Areas: Devices, Energy Materials, Materials Synthesis
... mammals, fish embryos). [28,43] Furthermore, in agreement with the higher acute toxicity observed for GaAs compared to InAs in this study (Table 1), a recent study using macrophage-like THP-a cells and a transformed human bronchial epithelial cell line BEAS-2B reported that GaAs (micron-scale particles ranging 0.2-3 lm and NPs < 100 nm) displayed higher toxicity than InAs particulates. [20] ...
Article
III-V semiconductor materials such as gallium arsenide (GaAs) and indium arsenide (InAs) are increasingly used in the fabrication of electronic devices. There is a growing concern about the potential release of these materials into the environment leading to effects on public and environmental health. The waste effluents from the chemical mechanical planarization process could impact microorganisms in biological wastewater treatment systems. Currently, there is only limited information about the inhibition of gallium- and indium-based nanoparticles (NPs) on microorganisms. This study evaluated the acute toxicity of GaAs, InAs, gallium oxide (Ga2O3), and indium oxide (In2O3) particulates using two microbial inhibition assays targeting methanogenic archaea and the marine bacterium, Aliivibrio fischeri. GaAs and InAs NPs were acutely toxic towards these microorganisms; Ga2O3 and In2O3 NPs were not. The toxic effect was mainly due to the release of soluble arsenic species and it increased with decreasing particle size and with increasing time due to the progressive corrosion of the NPs in the aqueous bioassay medium. Collectively, the results indicate that the toxicity exerted by the arsenide NPs under environmental conditions will vary depending on intrinsic properties of the material such as particle size as well as on the dissolution time and aqueous chemistry.
... Currently, GaAs nanowires are grown using gold seed particles, and trimethylgallium and arsine as precursor gases, but the method is general and other common precursor materials and techniques of seed particle formation can be used. GaAs as compound is a widely used in semiconductor applications in the microelectronics industry (Tanaka, 2004). ...
Article
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Background: Nanowires are a high-aspect-ratio material of increasing interest for a wide range of applications. A new and promising method to produce nanowires is by aerotaxy, where the wires are grown in a continuous stream of gas. The aerotaxy method can grow nanowires much faster than by more conventional methods. Nanowires have important properties in common with asbestos fibers, which indicate that there can be potential health effects if exposure occurs. No conclusive exposure (or emission) data from aerotaxy-production of nanowires has so far been published. Methods: Different work tasks during semiconductor nanowire production, post-production, and maintenance were studied. A combination of direct-reading instruments for number concentration (0.007-20 µm) and filter sampling was used to assess the emissions (a couple of centimeter from the emission sources), the exposure in the personal breathing zone (max 30 cm from nose-mouth), and the concentrations in the background zone (at least 3 m from any emission source). The filters were analyzed for metal dust composition and number concentration of nanowires. Various surfaces were sampled for nanowire contamination. Results: The particle concentrations in the emission zone (measured with direct-reading instruments) were elevated during cleaning of arc discharge, manual reactor cleaning, exchange of nanowire outflow filters, and sonication of substrates with nanowires. In the case of cleaning of the arc discharge and manual reactor cleaning, the emissions affected the concentrations in the personal breathing zone and were high enough to also affect the concentrations in the background. Filter analysis with electron microscopy could confirm the presence of nanowires in some of the air samples. Conclusions: Our results show that a major part of the potential for exposure occurs not during the actual manufacturing, but during the cleaning and maintenance procedures. The exposures and emissions were evaluated pre- and post-upscaling the production and showed that some work tasks (e.g. exchange of nanowire outflow filters and sonication of substrates with nanowires) increased the emissions post-upscaling.
... In some other works, the hot-carrier assisted IBSCs have been introduced using InAs/AlGaAs or InAlAs/InGaAs QDs (Hirst et al. 2014;Behaghel et al. 2019). The main problem with these materials is that they are toxic materials especially InAs was the most toxic material (Tanaka 2004). In our works, Cubic silicon carbide (3C-SiC) with an energy band gap of 2.3 eV is used as a host material that is near the optimum bandgap of IBSCs. ...
Article
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In this research work, hot carrier assisted intermediate band solar cells consisting of an absorber based on cylindrical silicon quantum dots (CQDs) with appropriate energy selective contacts (ESCs) are evaluated. Cylindrical shape nanoparticles benefit from two degrees of freedom (radius and height) to control their optical properties. First, the output performance parameters of a hot carrier solar cell with energy selective contacts based on quantum wells (QWs) and CQDs are compared. Then an array of CQDs is simulated and it is investigated that their optical properties can be tuned by controlling their heights, radii, and interdot spaces. A solar cell with ESCs based on CQDs results in better efficiency than a cell with ESCs based on QWs. An array of silicon CQDs inside a silicon carbide is analyzed and using the quantum confinement effect, an appropriate absorber was designed. The absorption coefficient for CQDs was calculated and the effect of their heights, radii, and inter dot spaces was analyzed. The key parameters are optimally designed which leads to obtaining a high absorption coefficient and consequently, the improvement of photocurrent of a hot carrier assisted intermediate band solar cell.
... [11][12][13][14][15][16][17][18][19] Gallium, a silvery metal, is extensively applied in chemical synthesis, fuel storage and the semiconductor industry, for example in light-emitting diodes and lasers. 20,21 Moreover, its nitrate salt has been used as an antitumor pharmaceutical owing to the high affinity of gallium for tumors. 22 Though the physiological function of gallium in the human body is not known, there is no doubt that it is carcinogenic and toxic to animals and humans. ...
Article
A versatile chemosensor 1 (E)-2-(((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)methylene)amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione, based on naphtalimide and julolidine moieties, was developed for a highly distinguishable and selective recognition of group IIIA metal ions (Al3+, Ga3+ and In3+). Sensor 1 exhibited significant ‘off-on’ fluorescence responses at 488 nm in the presence of Al3+ and at 570 nm in the presence of Ga3+ and In3+. The same emission of Ga3+ and In3+ could be distinguished through different color changes (from colorless to yellow for Ga3+ and no color change for In3+). Binding constants of 1 for Ga3+ and In3+ are the highest ones among those previously reported for the organic chemosensors, to date. The 2:1 binding modes between 1 and Al3+, Ga3+ and In3+ were proposed by ESI-mass and Job plot, and theoretical calculations.
... Future possibilities of indium complexes and nanoparticles of indium compounds for advanced materials application have been reported. The potential toxicity of indium has been suggested, [11] which also motivates study on the concentration of indium species from aqueous environments. Methods, such as chemical precipitation, [12] solvent extraction, [13][14][15][16] membrane filtration, [17] electrochemical deposition, [18] and adsorption, [19] have been proposed so far for the concentration of indium(III) from water. ...
Article
The reaction of aqueous solution of indium(III) chloride with a sodium titanate (Na2Ti3O7) was investigated. The remaining amount of the indium(III) in aqueous solution after the reaction with Na2Ti3O7 was examined to show the efficient collection of indium(III) from aqueous solution. The maximum collected indium(III) amount for Na2Ti3O7 was 2 mmol/g Na2Ti3O7, which is superior to other reported ion exchangers. The collected indium(III) existed as indium hydroxide particle with the size of several tens of nm at the particle (the size of microns) surface of H2Ti3O7, which formed from Na2Ti3O7 by the proton‐sodium exchange during the reaction.
... CIGS, CdTe, GaAs have band gaps closer to the ideal of 1.5 eV and achieve high laboratory conversion efficiencies of 21%, 21%, 29% respectively [44][45][46][47][48]. They contain toxic materials which can be a problem during the manufacturing process, but in particular during disassembly, since specific recycling facilities are required [49][50][51]. Furthermore, CIGS solar cell producers have benefited from indium being a by-product of zinc smelting and refining. ...
Article
Worldwide, over 1.1 billion people have no access to electricity. The consequences for the affected people include health hazards from fuels used for lighting, limits to learning when it gets dark, a short productive day and high expenditures on lighting alternatives. Since 85% of affected people live in rural areas in developing countries, increasing access to electricity through grid supply is logistically and financially challenging. As a potential solution to this issue off-grid solar chargers have been gaining popularity. This technology is under continuous development to achieve lower costs, faster battery charge and more electricity generation to prolong light hours. This review contains a comprehensive analysis of possible improvements to solar lights and the role solar PV concentrators can play in it. It aims to provide the reader with a critical comparison of existing solar PV concentrators and to consider the advantages and drawbacks if applied to portable solar systems used in developing countries. From this review, static nonimaging concentrators have been identified as best suited since they are easy to operate and maintain and have shown high reliability. A detailed comparison of existing static nonimaging concentrators is presented in this work and their suitability for being deployed in portable solar systems in developing countries is evaluated. It concludes that the existing designs need adjustment if to be used for this purpose. Thus, novel concentrator designs for portable solar systems for developing countries are needed to facilitate more off-grid solar power generation. It is the aim therefore of this review to stimulate more research in this field.
... It appears that Ga is toxic when released from particles, although the physical characteristics of the particles themselves also contribute to the toxic effects. Ga is listed as hazardous in California in the United States; however, it is not listed as a toxic substance in Taiwan (Tanaka, 2004;Yamauchi et al., 1989). ...
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Gallium (Ga) is one of the intermetallic elements that has been used in cancer treatment for a long time. However, Ga compounds are increasingly being used to make high-speed semiconductors and photoelectric devices. The current work investigated physiological and pathological changes in zebra fish ( Danio rerio) exposed to various Ga ³⁺ levels (0.55, 1.5, and 3.85 mg/L) over a 14-day test period. Decreases in oxygen consumption were significant ( p < 0.05) for groups exposed to 3.85 Ga ³⁺ mg/L; this was associated with the fusion of zebra fish gills lamellae. Serum biochemical changes (including aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) were consistent with observations of damage to organelles within the hepatocytes at higher Ga ³⁺ exposure levels (1.5 and 3.85 mg/L) in zebra fish. We propose <0.55 Ga ³⁺ mg/L as a biologically safe concentration that can be used to establish water quality criteria for this teleost model.
... A few case studies of workers exposed to insoluble indium compounds have shown that inhaled indium can cause interstitial lung damage (Hamaguchi and others, 2008, and references therein). Furthermore, among the metal arsenic compounds used in the semiconductor industry, indium arsenide has proven to cause the greatest impairment to lung function (Tanaka, 2004, and references therein). To prevent negative effects from occupational indium exposure, OSHA has set a limit of 0.1 milligram per cubic meter for indium-bearing dust in workplace air over an 8-hour workday (Occupational Safety and Health Administration, 2013b). ...
... Among various metal ions, gallium exists as a salt form in diaspore, sphalerite, germanite, bauxite, zinc ores and coal not free form in nature [6,7]. It is utilized in semiconductor devices, usually in the form of gallium arsenide or gallium nitride which in turn is employed in light emitting diodes (LEDs) [8,9]. On the other hand, Ga(III) is considered to be carcinogenic and toxic to humans and animals although any physiological function is not known in the human body [10]. ...
... In animals, pulmonary toxicity has been seen for a wide array of indiumcontaining compounds, along with testicular damage and developmental toxicity of InCl 3 , InAs, and InP ( [6•, 8] and references therein). Comparative studies with As 2 O 3 , NaAsO 3 , As 2 Se 3 , InP, InCl 3 , GaAs, AlGaAs, or CuGaSe 2 suggest that indium itself is responsible for significant toxicity [35][36][37]. However, few studies have been done to elucidate the effects of chronic exposure to low-levels of indium compounds that the general population may encounter. ...
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The rapid growth of new electronics and energy technologies requires the use of rare elements of the periodic table. For many of these elements, little is known about their environmental behavior or human health impacts. This is true for indium and gallium, two technology critical elements. Increased environmental concentrations of both indium and gallium create the potential for increased environmental exposure, though little is known about the extent of this exposure. Evidence is mounting that indium and gallium can have substantial toxicity, including in occupational settings where indium lung disease has been recognized as a potentially fatal disease caused by the inhalation of indium particles. This paper aims to review the basic chemistry, changing environmental concentrations, potential for human exposure, and known health effects of indium and gallium.
... Later reports have shown that silicon and its related material derivatives (SiO 2 and Si 3 N 4 ) have been connected to chronic neuroinflammation, most likely due to chemical reactivity and physical modulus mismatch [11][12][13]60]. Many other semiconductor materials demonstrate traits that would not allow their use in reliable INIs, such as gallium arsenide, and have demonstrated biological toxicity [61]. Diamond and gallium nitride have demonstrated elements of anodic oxidation and subsequent material corrosion [62,63]. ...
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Intracortical neural interfaces (INI) have made impressive progress in recent years but still display questionable long-term reliability. Here, we report on the development and characterization of highly resilient monolithic silicon carbide (SiC) neural devices. SiC is a physically robust, biocompatible, and chemically inert semiconductor. The device support was micromachined from p-type SiC with conductors created from n-type SiC, simultaneously providing electrical isolation through the resulting p-n junction. Electrodes possessed geometric surface area (GSA) varying from 496 to 500 K μm2. Electrical characterization showed high-performance p-n diode behavior, with typical turn-on voltages of ~2.3 V and reverse bias leakage below 1 nArms. Current leakage between adjacent electrodes was ~7.5 nArms over a voltage range of −50 V to 50 V. The devices interacted electrochemically with a purely capacitive relationship at frequencies less than 10 kHz. Electrode impedance ranged from 675 ± 130 kΩ (GSA = 496 µm2) to 46.5 ± 4.80 kΩ (GSA = 500 K µm2). Since the all-SiC devices rely on the integration of only robust and highly compatible SiC material, they offer a promising solution to probe delamination and biological rejection associated with the use of multiple materials used in many current INI devices.
... However, the limited wafer size of III-V materials (3 or 4 inch), which increases manufacturing cost, is a critical drawback. In addition, the use of III-V semiconductors requires careful attention due to their toxicity [19], and despite the advances in the InP-based PICs [20,21], ...
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Monolithic integration of III-V semiconductor devices on Silicon (Si) has long been of great interest in photonic integrated circuits (PICs), as well as traditional integrated circuits (ICs), since it provides enormous potential benefits, including versatile functionality, low-cost, large-area production, and dense integration. However, the material dissimilarity between III-V and Si, such as lattice constant, coefficient of thermal expansion, and polarity, introduces a high density of various defects during the growth of III-V on Si. In order to tackle these issues, a variety of growth techniques have been developed so far, leading to the demonstration of high-quality III-V materials and optoelectronic devices monolithically grown on various Si-based platform. In this paper, the recent advances in the heteroepitaxial growth of III-V on Si substrates, particularly GaAs and InP, are discussed. After introducing the fundamental and technical challenges for III-V-on-Si heteroepitaxy, we discuss recent approaches for resolving growth issues and future direction towards monolithic integration of III-V on Si platform.
... Therefore, food chain could be a critical junction of pathway that Ga and In enter the human body. Besides major adverse effects on lungs via inhalation, Ga and In can accumulate in stomach and kidney, and affect them detrimentally [53,61]. Thus, in the processes of comprehensive utilization and disposal of by-products of No. 9 coals, prevention on migration of Ga and In into environmental media and further to food chain is also necessary. ...
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To provide a comprehensive insight into the enrichment mechanism of gallium and indium in No. 9 coals, eighteen samples were collected from Anjialing mine, Ningwu Coalfield, Shanxi Province for coal petrological, mineralogical and geochemical analyses. The results suggested that Ga and In enrichment mainly hosted in the top horizons, with average concentration coefficients of 8.99 and 2.73 respectively, compared with the rest of horizons (2.46 for Ga and 1.69 for In). Source apportionment indicated that Ga and In were mainly derived from bauxite of Benxi Formation in Yinshan Oldland, while In could originate from felsic magmatic rocks in Yinshan Oldland as well. In addition, weak oxidation condition, medium to intensive weathering, transgression and input of terrestrial higher plants had positive effects on Ga and In enrichment. With the rapid expansion of emerging electronics manufacturing, Ga and In, of which potential risks on human health were neglected previously, were recently considered as hazardous elements. Therefore, this paper also discussed the potential pathways that these elements threatened human health. We suggested that potential risks on environment and human health caused by Ga and In enrichment in coals and coal-related products should be taken into account besides their economic value.
... The development of efficient probes for the detection of metal ions has received considerable attention due to their important roles in medicine, living systems and the environment [1]. Although gallium does not occur in nature, gallium salt is often found in diaspora, sphalerite, germanite, bauxite, zinc ores and coal. ...
... Previous studies revealed that excessive intake of Ga by animals resulted in the accumulation of Ga in bones and led to impaired kidney function and failure of the nervous system. 10,11 Ga appears to inhibit DNA synthesis by its action on ribonucleotide reductase 12 and it interferes with the cellular immune function. 13 Ga has antimicrobial effects to inhibit the growth of pathogenic bacteria (Pseudomonas aeruginosa) and prevents biofilm formation, so Ga is a promising new therapeutic agent against bacterial infections. ...
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Although gallium (Ga) is a rare element, it is widely used in semiconductor devices. Ga contamination of the environment has been found in semiconductor-producing countries. Here, the physiological and molecular impacts of Ga in the model plant Arabidopsis thaliana were investigated in medium culture. The primary symptom of Ga toxicity is inhibition of root growth. The increased production of malondialdehyde (MDA) suggests that Ga stress could cause oxidative damage in plants. Roots were the main Ga accumulating sites. The distinctive Ga granules were deposited within the intercellular space in roots. The granules indicate Ga(OH)3 precipitation, which indicates immobilization or limited translocation of Ga in A. thaliana. Ga stress induces root secretion of organic acids such as citrate and malate. The expression of the transporters AtALMT and AtMATE, responsible for citrate and malate secretion, respectively, were elevated under Ga stress, so the secretion may play a role in the resistance. Indeed, supplying exogenous citrate significantly enhanced Ga tolerance. The overall response to Ga exposure in A. thaliana is highly similar to that with aluminum stress. Our findings provide information for risk assessment in Ga-contaminated soil.
... Apart from elemental Ga, the wide application of high-purity As compounds in the semiconductor industry and ensuing waste products such as computer circuitboards and photodiodes calls for attention to the physiological toxicity of artificial Ga-bearing compounds such as GaAs (Dupuis, 1984;Robinson, 1983;Tanaka, 2004). Strong evidence has been presented that GaAs is not only a toxin that directly damages the lungs and reproductive organs of animals but also a human carcinogen. ...
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Gallium exhibits weak metallic properties owing to its proximity to non-metals in the periodic table, yet is volatile in extra-terrestrial bodies and fairly reactive in nature. It has been used extensively to elucidate the Solar System evolution, planet interior differentiation, and terrestrial processes. However, Ga speciation and transformation in various planetary compartments and the dynamics of its trans-reservoir pathways remain to be fully resolved. Although recent studies and the development of modern analytical techniques for Ga isotopes have markedly improved our understanding of Ga geochemistry, a systematical summary of state-of-the-art knowledge appears to be long overdue. Here we provide an overview of the geochemical properties of Ga in different reservoirs, including meteorites and Earth's interior and exterior compartments, and a timely review of Ga isotopic geochemistry. We also provide a first tentative estimate of total masses of Ga in different compartments and the trans-reservoir Ga flux, based on the published data. This compilation reveals clearly the lack of geochemistry data of Ga in Earth's interior, the imbalance of oceanic Ga budget and the potential implications of Ga isotopes, stimulating future systematic studies of Ga and its isotopes in geosciences and related fields.
... It is a common n-type dopant in manufacturing semiconductors, with gallium arsenide (GaAs) being the second, after doped silicon, most commonly used semiconductor material in electronics industry such as integrated circuits (ICs), light emitting diodes (LEDs), laser diodes (LDs), and solar cells (Neamen, 2012). GaAs and other arsenic-based III-V semiconductors, such as indium arsenide (InAs), may impose serious toxic and carcinogenic pulmonary effects on workers in the semiconductor industry (Tanaka, 2004) who are at high risk of exposure to significant levels of arsenic especially through inhalation (Ham et al., 2017;Park et al., 2010). High levels of urinary arsenic metabolites have been reported in workers from a manufacturing plant (Byun et al., 2013), and were correlated to oxidative injury (Hu et al., 2006). ...
Article
Arsenic is well-recognized as one of the most hazardous elements which is characterized by its omnipresence throughout the environment in various chemical forms. From the simple inorganic arsenite (iAsIII) and arsenate (iAsV) molecules, a multitude of more complex organic species are biologically produced through a process of metabolic transformation with biomethylation being the core of this process. Because of their differential toxicity, speciation of arsenic-based compounds is necessary for assessing health risks posed by exposure to individual species or co-exposure to several species. In this regard, exposure assessment is another pivotal factor that includes identification of the potential sources as well as routes of exposure. Identification of arsenic impact on different physiological organ systems, through understanding its behavior in the human body that leads to homeostatic derangements, is the key for developing strategies to mitigate its toxicity. Metabolic machinery is one of the sophisticated body systems targeted by arsenic. The prominent role of cytochrome P450 enzymes (CYPs) in the metabolism of both endobiotics and xenobiotics necessitates paying a great deal of attention to the possible effects of arsenic compounds on this superfamily of enzymes. Here we highlight the toxicologically relevant arsenic species with a detailed description of the different environmental sources as well as the possible routes of human exposure to these species. We also summarize the reported findings of experimental investigations evaluating the influence of various arsenicals on different members of CYP superfamily using human-based models.
... mg kg -1 Ga was detected in nearby agricultural soils (Połedniok et al., 2012). Ga contamination in soils may cause health risks to humans via food chains because its accumulation in humans can cause acute and chronic toxicity to the lungs, kidneys, and reproductive organs and even carcinogenesis (Chepesiuk, 1999;Tanaka, 2004;Ivanoff et al., 2012). Therefore, it is necessary to investigate the accumulation of Ga in soil-crop systems to evaluate the human health risk associated with soil Ga contamination. ...
Article
Gallium (Ga) is widely used in high-tech industries and is an emerging contaminant in the environment. This study aimed to determine Ga speciation in soils and Ga accumulation in rice plants (Oryza sativa L.) grown in three Ga-contaminated soils. The results showed that, among the soils, the acidic soil with a coarse texture had the highest soil Ga availability, which enhanced Ga uptake by rice roots. The Ga K-edge X-ray absorption near edge structure and sequential extraction results of the soils showed that the predominant species of Ga associated with iron hydroxides transformed to Ga(OH)3 precipitates, and the residue fraction increased with rice-growing time, resulting in lower Ga uptake by rice roots in the second half period of rice cultivation. A large fraction of Ga was accumulated in the rice roots, with only a small portion of Ga was transferred to the shoots and then to the rice grains. This study revealed that Ga speciation in soil-rice plant systems varied during rice cultivation and determined soil Ga availability to rice plants. Gallium accumulated in rice grains is distributed homogenously in the endosperm of the grains, suggesting a potential risk to public health via the intake of rice grains harvested from Ga-contaminated paddy fields.
... In most compounds, gallium has an oxidation state of +3. Gallium(III) arsenide and gallium(III) nitride are mainly used as semiconductor materials in the electronics industry to produce optoelectronic devices such as laser diodes and light emitting diodes (LEDs) [2]. Gallium(III) can also be used as a dopant in semiconductors for the production of transistors [3]. ...
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Abstract Three novel fluorescent probes, 2-(2′-hydroxyphenyl)-4-chloromethylthiazole (1), 2-(2′-hydroxyphenyl)-4-hydroxymethylthiazole (3), and 2-(2′-hydroxyphenyl)-4-iodomethylthiazole (4) were designed for the sequential recognition of Ga3+ and pyrophosphate ions in acetonitrile. Probe 1 selectively detected Ga3+ through a “switch on” response, showing a good association constant (Ka = 6.24 × 104 M−1) and binding with Ga3+ ions in a 1:1 stoichiometry. An in situ generated 1-Ga3+ (1:1) ensemble detected H2P2O73–ions sequentially through a “switch off” response. The “switch on” response occurred with selective complexation of Ga3+ ions due to combined excited state intramolecular proton transfer (ESIPT) and chelation induced enhanced fluorescence (CHEF) effects. An ensemble of 1 and gallium(III) was more selective for pyrophosphate ions than any other anion.
... The observed decrease could be attributed to the potential toxic effects of In on the spermatogenesis process in testicles, diminishing the number of spermatids in the seminiferous tubules. Indeed, many previous studies conducted in our laboratory [22] and those of others [19,42] demonstrated a necrotic effect of In in the rat testicles. In the present work, parenteral administration of In was able to significantly alter the normal histologic conditions of the rat testicles, inducing disintegration of the seminiferous epithelium with a decrease in the number of functional and active tubules. ...
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Background Aluminum and indium are widely used in industrial manufacturing, in pharmaceutical products, in medical treatments, and in food packaging, so they could reach organisms by different way. In order to clarify whether these elements are dangerous, we already demonstrated the ultrastructural modifications observed in the testicles, the epididymides, and the seminal vesicles of rat. Their pro-oxidative effect was also confirmed concomitantly to a decrease in anti-oxidant defenses in the blood, the testicles, and the liver. Thus, it seemed very logic to evaluate damages in the reproductive organs, especially on the exocrine and endocrine functions of the testicles. Methods Aluminum and indium were intraperitoneally administered to male Wistar rats. Sperm solution was obtained from cauda epididymides. Motility, viability, density, and malformation of spermatozoa solution were assessed. Serum total unconjugated testosterone concentrations were measured using RIA technique. Results Our results showed a decrease in weight of the testicles, epididymides, and seminal vesicles of indium-treated rats and an increase in the weight of their kidneys. A decrease in motility, viability, and density of epididymides stored sperm as well as generation of many spermatozoa malformations was also observed especially in indium-treated rats. Testosterone levels were increased in indium but were enhanced in aluminum group. This confirmed our previous studies showing that aluminum and indium are toxic for the testicular tissues. This could be explained by the generation of reactive oxygen species (ROS) affecting strongly the exocrine and the endocrine functions of the testicles. Conclusion Aluminum and indium are disturbing elements for the exocrine and endocrine functions of rat testicles.
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Our environment is becoming more polluted due to the commercial applications of toxic chemicals and heavy metal cations. So, for the sensing of heavy metal cations in aqueous solution N,N'-(cyclohexane-1,2-diyl)bis(2,5-dimethoxybenzenesulfonamide)...
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The increase in industrialization and urbanization leads to an increase in the quantity and variety of anthropogenic pollutants, it is dangerous for organisms when reaching the groundwater. Toxic substance response is the basic research area of the metals exist in environment. In this study, it is aimed to investigate the accumulation and formation of oxidative stress of mixtures of Aluminum, chromium, cobalt, cadmium and arsenic metals in drinking water and irrigation water exposure limits on gill tissues of Zebra fish. Metal accumulation was analyzed with ICP-MS, DNA damage with RAPD-PCR method, and the antioxidant enzymes was evaluated by qRT-PCR method. Two different concentration series were used to investigate the genotoxic effect; drinking water limits of arsenic, cadmium, chromium, cobalt and aluminum, respectively 10 μg / L, 5 μg / L, 50 μg / L, 10 μg / L, 300 μg / L and within the allowed irrigation waters limits at 100 μg / L, 10 μg / L, 100 μg / L, 50 μg / L and 5000 μg / L respectively with the chronic treatment of 5,10, and 20 days. When metal accumulation evaluated, only cobalt accumulation was not significantly increased as the time and concentration increase in Zebrafish gill tissue. Accumulation of the other metals also increased. RAPD analysis results showed that % genomic template stability was decreased as the concentration and exposure time increase. Although gene expressions of Catalase and CuZn-SOD which antioxidants elements were significantly increased compare wtih control, gene expressions were improved with time.
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The management of solid waste is one of the major challenges faced by any developing country. In recent years, the increase in the urban population, together with their changes in production/consumption patterns, the improvement in peoples living standards and the proliferation of suburbs have led to a significant increase in solid waste in Morocco, with an overall production of 6.9 million tons per year. The quantity of municipal solid waste (MSW) is about 5.3 million tons per year, equivalent to 0.76 kg per day per capita. Waste generated in rural areas has been estimated as 1.6 million tons per year, corresponding to 0.3 kilo per capita per day. Systematic waste collection practice is a major bottleneck, yet it is a major factor that contributes to the success of any waste management program. According to official estimates, approximately 82% of the urban population and only 20% of the rural population benefit from the existing collection services. The low rate of collection causes open dumps and the dispersion of garbage in the streets. According to a recent survey in 2013, only 37% of the collected waste are deposited in controlled landfills. Most of the waste dumping sites are located in the former quarries. This mismanagement causes significant negative impact on the environment and water resources since 40% of the landfills are closer to the rivers and aquifers. The release of greenhouse gases, as well as the proliferation of insects are also a serious nuisance, causing health and environmental problems. In addition, the sector must also confront challenges manifested by the persistence of the nearly 200 landfills that have not yet been rehabilitated. A World Bank study in the year 2003 estimated costs related to the weak performance of the solid waste management system as 0.5% of the gross domestic product (GDP). To deal with the challenges posed by the mis-management of household waste, several measures and initiatives were undertaken by the government. This includes, among others, the launch of the National Household Solid Waste Program (NHSWP) in the year 2007 by the Moroccan Ministry of Interior and the Moroccan Secretary of State for Water and Sustainable Development, with the support of the World Bank. The cost of the program was estimated to be 40 billion MAD, allocated in the following proportions: collection and cleaning: 72%; construction and operation of controlled landfills: 14.6%; rehabilitation and closure of the dumps: 6.2%; field studies, follow-up and control: 3.5%; sorting, recycling and valorization: 1.8%; communication, awareness and training: 1.8%. In Morocco, designated public landfills are managed by 12 companies and they have achieved a turnover of 268 million dirhams and employed 150 agents, in addition to the creation of many direct and indirect jobs related to sorting, transporting and recycling services. Landfill leachate is considered as a high-strength wastewater which is often characterized by high salinity, organic loads, and a complex mixture of hardly biodegradable substances such as proteins, lipids, phenolic compounds and toxic ammonium ions. The treatment of leachate is an important issue in Morocco because there is no treatment system (in-situ or ex-situ) that achieves complete treatment of the leachates. Therefore, in order to meet the discharge limits, most of the treatment process is limited to forced evaporation. This process leads to odor problems near the treatment site and the alteration of surface and ground water quality. At present, this is a social nuisance and a burden to the municipalities. However, some newly established controlled landfills have introduced processes such as reverse osmosis (RO), in the city of Rabat, and a two-step process comprising of leachate pretreatment by an ultrafiltration membrane bioreactor followed by RO treatment (the Evalix process), in the city of Meknès. From a resource recovery viewpoint, Morocco has confirmed its ambitions to upgrade biogas production through two major biogas capture/valorization initiatives in the cities of Fez and Oujda, respectively. The new landfill located in the city of Fez is able to upgrade a part of the biogas generated from organic waste for the production of electricity (487,170 KW). It is noteworthy to mention that the cumulative electrical energy injected into the public lighting network in the city of Fez reached 5.8 million KW in one year, representing approximately 25% of the energy required for street lighting in Fez city. Concerning sorting activities, several new projects were launched for social reasons, especially to integrate and educate the manual sorters (ragpickers). The sorters were brought together to a cooperative society so that their activities were monitored and their security conditions can be enhanced. This includes the establishment of sorting hangars, administrative premises and cloakrooms. Marrakesch city has constructed the first recycling center at new Marrakech controlled landfill, one of the largest in North Africa.
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The implementation and exploration of liquid metals for soft electronics, especially electronic skins (e-skins), are fast increasing. The growing field has received special attention since research regarding gallium-based alloys has intensified as these alloys are much safer in comparison to their more hazardous counterpart, mercury. Liquid metal alloys of gallium provide unique physical and chemical properties for e-skin. These properties originate from their high thermal and electrical conductivities and the fact that the liquid metal is an electronic melt in contrast to the ionic liquid. The formation of 2-D oxides on the surface of liquid gallium alloys, with large van der Waals forces, also adds to their uniqueness. Liquid metals, whether in bulk form or particulated morphologies, provide stretchabilities that surpass any other systems, allowing for the formation of super malleable e-skins. As such, they present certain opportunities for developing elements with extraordinary softness, malleability, and skin compatibility: stretchable wires and electrodes, memories, electronic components such as resistors, coils, diodes, and transistors, soft sensors, energy harvesting/storage elements, and self-healing systems. Presence of the 2-D metal compound skin also helps in accessing the non-Newtonian characteristics of gallium-based alloys that permit the formation of microparticles/nanoparticles and specific fluidics and grant printability in three dimensions. Liquid alloys of gallium, their properties, and applications for e-skins are discussed in this review, and the wealth of opportunities for future applications within soft and stretchable electronics is explored.
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Research on metal price determinants has been driven by increasing price volatilities and realization of metals as financial assets. A sound understanding of metal prices enables producers, consumers, policy makers and traders to anticipate and better prepare themselves for short and long-term price trends. Metal prices are related to each other via their nature of either being jointly produced or jointly consumed. While the effects of joint production of metals have been the subject of increased analysis lately, the effects of joint consumption on metal prices have yet to be studied systematically. Therefore, we aim to analyze the effects of both joint consumption and joint production on the causality relationship between metal prices. In doing so, we use the Toda Yamamoto approach to conduct pair-wise Granger-causality tests between various metals that are either jointly produced or jointly consumed. Our results indicate that joint-consumption of metals has a significant impact on the Granger-causality relationship between metals and that it is indeed an important determinant of metal prices.
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From environmental safety and resource recovery view point, a novel method of recycling gallium arsenide (GaAs) from scrapped GaAs-based Integrated circuits (ICs) was proposed in this study. Hydrothermal-buffering method (HBM) has been developed in which oxidant (H2O2) in the presence of phosphate buffer solution reacted with ICs under hydrothermal condition. The results have shown that packaging material was effectively decomposed without any significant loss of GaAs under HBM condition. Gallium and arsenic recovery rates were 99.9% and 95.5%, respectively. In addition, thermodynamically stable regions of Ga and As species in aqueous systems were identified by Eh-pH diagram. The function of HBM has been studied and discussed in detail. Results have shown that Na+ and OH- ions provided by buffer system accelerate the degradation of packaging materials. Meanwhile, the OH- plays an irreplaceable role in the recovery of GaAs. The states of As on the surface of the recovered GaAs were mainly positive trivalent and pentavalent, and the corresponding compounds were As2O3 and Na2HAsO4 respectively. Under optimum conditions, without any release of toxic gasses to the environment, 91.2% of the packaging materials was decomposed where probably free radical reaction was the main mechanism and the probable decomposition pathways of packaging materials were investigated. Study provides an efficient and environmentally friendly process to treat ICs packaging material and recover maximum GaAs for further use.
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Indium and gallium are used widely in modern industry, mostly for the production of semiconductors. They are considered as Technology-Critical Elements and have therefore received growing attention in the past few years. We investigated the influence of different types of humic substances on the transport of indium and gallium in laboratory-scale, saturated column experiments, to gain understanding of their mobility in natural environments. We evaluated the effect of different humic substances on the transport of indium and gallium in quartz sand: a commercial humic acid (Aldrich Humic Acid, AHA), a fulvic acid (Suwannee River Fulvic Acid, SRFA) and an aquatic natural organic matter (Suwannee River Natural Organic Matter, SRNOM). The impact of the flow rate and the influence of different concentrations of organic matter were also investigated. Indium was shown to be more mobile than gallium in the presence of humic substances. The mobility of indium in sand was highest for SRNOM, followed by SRFA and then AHA, while for gallium the order was SRFA > SRNOM > AHA. These results can be significant in understanding the mobility of indium and gallium in soils with various compositions of organic matter.
Article
To understand the risk of two emerging contaminants, gallium (Ga) and indium (In) to humans via rice consumption, effects of soil properties and concentrations of spiked Ga/In on the accumulation of Ga and In in rice grains were investigated. A pot experiment was conducted, and paddy rice was grown in three soils with different pH values and Al availabilities (i.e., Pc, TWz and Cf), which were spiked with various Ga and In concentrations. The growth index and concentrations of Ga, In, and Al in plant tissues and soil pore water were measured. Results revealed that the concentrations of Ga and In in soil pore water increase with the spiking of Ga or In in all of the tested soils, but the biomass of roots and shoots does not significantly decrease. The accumulation of Ga in shoots and brown rice was significantly reduced in high available Al acidic soils (Pc soils), but this accumulation was significantly increased in low available Al acidic soils (TWz soils), which can be explained by the competitive uptake between Ga and Al by rice plants. The extent of competitive effects between In and Al was less than that between Ga and Al because of the lower solubility and translocation capability of In than those of Ga in soil-rice systems. However, significant differences in the concentrations of Ga and In in brown rice in neutral soils (Cf soils) among the Ga or In treatment were not observed. In addition, the iron plaque formed on the root surface can serve as a barrier to reduce the accumulation of Ga in rice plants. This study suggested that the risk of accumulation of Ga and In in rice grains should be of concern when paddy rice is grown in acidic Ga- or In-contaminated soils with low Al availability.
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Searching for energetic photovoltaic absorbers is a favorable solution to the current energy crisis. As a star material for solar cells, MAPbI3 (MA=CH3NH3) has a suitable bandgap, strong optical absorption, great defect tolerance and high certified power conversion efficiency (PCE) up to 25.2%. However, the lead toxicity and poor long-term stability limit its application in photovoltaic devices. To break through these bottlenecks, we design two-dimensional (2D) Dion-Jacobson (DJ) type (n=3) chalcogenide perovskites A'La2B3S10 (A'=Ba, Sr, Ca; B=Hf, Zr), with optimal bandgap, strong optical absorption, high carrier mobility and excellent optoelectronic properties, based on the powerful first-principles and advanced HSE06 calculations. Especially, we find that, superior to MAPbI3, 2D A'La2B3S10 perovskites have the following several outstanding properties. (1) They are Pb-free and environment-friendly. (2) The structural stability is better than MAPbI3. (3) The direct bandgap (~1.33 eV of BaLa2Hf3S10), i.e., the optimal value of the SQ-limit, is more suitable than MAPbI3 (~1.55 eV) with a 0.22 eV energy-loss spectrum. (4) The carrier mobility (1.8-2.6×10³ cm²V⁻¹s⁻¹) is larger than MAPbI3 (~37 cm²V⁻¹s⁻¹). (5) The optical absorption (~6×10⁵ cm⁻¹) in the visible-range is three times stronger than MAPbI3 (~2×10⁵ cm⁻¹). (6) The estimated PCE (~30.9% in BaLa2Hf3S10) is higher than MAPbI3 (~30%). These amazing characteristics indicate that 2D A'La2B3S10 perovskites are promising absorbers for photovoltaics.
Chapter
A linear concentrator is used to increase the incident solar radiation on a photovoltaic cell and consequently the electricity output. However, the energy conversion efficiency of PV cell decreases with increasing in the cell temperature cell for high solar radiation. This chapter covers specifically the Linear Concentrating Photovoltaic (LCPV) system. In this chapter, the application and mathematical model of LCPV systems are explained in brief. Moreover, as the efficiency of LCPV system depends on the temperature of PV cell, thus the LCPV requires a cooling system which is the main topic of this chapter. The mathematical model of water loop system, two-phase loop system and vapor compression refrigeration system are presented and discussed. Finally, the chapter concludes that the use of heat absorbed and not converted into electric energy by PV cell can be very useful for water heating, therefore the system can be used as hybrid system to generate electric power and hot water.
Chapter
Organic photovoltaics is based on molecular semiconductors with extended pi‐electron systems expanding over the carbon backbone. This can be small to large molecules, fullerenes, oligomers and polymers. These materials offer the possibility to engineer the bandgap of the semiconductor by altering the chemical structure of the molecules. Besides changes in the color, varying from red to yellow over green and blue to purple, this also has technical implications. For indoor applications under artificial light, the optimum bandgap is in the range of 1.9eV, matching the bandgap of a variety of OPV materials. Organic solar cells can be produced by printing and coating in roll‐to‐roll processes and even by digital inkjet printing, offering fast and cost efficient production and the possibility to print nearly arbitrarily shaped solar cells. The low light intensity and related low device currents open the path to use different materials, device setups and dimensions as compared to full sun applications, where high currents demand a highly effective current collection. On the other hand it raises the requirements for defect free devices with very high values for the parallel resistance. This chapter will discuss these opportunities and challenges from basics to the implementation of indoor optimized OPV devices.
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The emerging contaminants gallium (Ga) and indium (In) are extensively used in advanced industries and are considered as toxic to humans. Limited information is available on the dynamics of Ga and In in soil-upland crop systems. Therefore, this study aimed to investigate the effects of Ga and In on the growth and uptake of Ga and In by wheat plants grown in Ga- and In-contaminated soils. The wheat seedlings were planted in soils of different properties spiked with various Ga and In concentrations (50, 100, 200, and 400 mg kg⁻¹). The plant-available Ga, In, and Al in the soils were extracted by 0.02 M CaCl2, and their concentrations in plant tissues of wheat seedlings and plant biomass were determined after harvesting. The results indicated that the Al toxicity of wheat seedlings increased with Ga and In concentrations in acidic soils. Indium phytotoxicity was found in both neutral and acidic soils. Plant analysis results indicated that the concentration of Ga and In in roots was approximately one order of magnitude higher than that in the shoots of wheat seedlings, and the capability for Ga translocation from roots to shoots was higher than for In. The results of this study suggest that the dynamics of Ga and In in soil-upland crop systems is strongly dependent on the soil properties, such as pH and Al availability.
Article
Novel atmospheric pressure glow discharge (APGD) microplasma systems, sustained between a miniaturized flowing liquid cathode (FLC) and either a pin-type anode or a He nozzle jet were investigated for the determination of Ga and In by the optical emission spectrometry (OES). The most influential working parameters, i.e., solution flow rate, acid concentration, discharge current, and He flow rate, were optimized for both studied systems. Furthermore, the effect of the addition of low molecular weight organic compounds (LMWOCs) into the FLC solution on the signals intensity of Ga and In was investigated. Subsequently, the impact of concomitant ions on the signals intensity of Ga and In was thoroughly studied and it was established that both studied methods are relatively resistant to the matrix effects. Under the optimized conditions, the detection limits (DLs, assessed on the basis of the 3σ criterion) of the studied elements were similar for both discharges and ranged between 1.8-2.3 μg L⁻¹ for Ga and 0.37-0.40 μg L⁻¹ for In. The received DLs were therefore better than those obtained for other spectrometric methods being premised upon microplasma systems and comparable with those obtained by currently employed large-scale instrumentation. The system with the pin-type anode was successfully applied for the Ga and In determination in four leachates of solders and electronic scrap as well as river water, using external calibration with simple standard solutions. The received results were compared to those obtained from ICP-OES or ICP-MS measurements and their recoveries were fallen within the range of 98-114%, confirming the excellent accuracy and reliability of the developed FLC-APGD-OES method.
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Chronic toxicity of indium arsenide (InAs) and arsenic selenide (As2Se3) was studied in male Syrian golden hamsters which received InAs or As2Se3 particles, each containing a total dose of 7.5 mg of arsenic, by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total lifespan, the cumulative body weight gain of the hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the As2Se3 group when compared with that in the control group. However, the survival rate for the InAs group was significantly higher compared with the control group, but not for the As2Se3 group when compared with the control group. During the animals' total lifespan, one lung adenoma was seen in the 27 hamsters in the InAs group and one lung adenoma in the 23 hamsters in the control group. No tumors of the lung were observed in the As2Se3 group. Malignant tumors outside the lung appeared in four hamsters in the InAs group and in two in the As2Se3 group. No non-lung malignant tumours were seen in the control group. Total tumor incidence rates were 25.9% (7/27) in the InAs group, 10.3% (3/29) in the As2Se3 group and 8.7% (2/23) in the control group. There were therefore no significant differences in tumor incidence between the InAs or the As2Se3 group, and the control group.
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Gallium arsenide (GaAs), a group III-VA intermetallic semiconductor, possesses superior electronic and optical properties and has a wide application in electronic industry. Exposure to GaAs in the semiconductor industries could be a possible occupational risk. The aim of the present study was to determine the dose-dependent effect of single oral exposure to GaAs (500, 1000, or 2000 mg/kg) on some biochemical variables in heme synthesis pathway and few selected physiological variables at d 1, 7, and 15 following administration. The results indicate that GaAs produced a significant effect on the activity of δ-aminolevulinic acid dehydratase (ALAD) in blood and heart (particularly at d 7) following exposure to 2000 mg/kg, whereas urinary δ-aminolevulinic acid (ALA) excretion was elevated only at d 7. No marked influence of GaAs on blood hemoglobin, zinc protoporphyrin, and packed cell volume was noticed. Blood glutathione (GSH) was significantly reduced at d 7, but remained unchanged at two other time intervals. On the other hand, heart GSH contents remained uninfluenced on GaAs exposure. Most of the physiological variables, viz. blood pressure, heart and respiration rate, and twitch response, remained unchanged, except for some minor alterations observed at d 7 and 15 following exposure to GaAs at a dose of 2000 mg/kg. Blood gallium concentration was not detectable in normal animals and rats exposed to 500 mg/kg GaAs. Blood arsenic concentration was, however, detectable even at the a lower dose level and increased in a dose-dependent manner. All these changes showed a recovery pattern at d 21, indicating that the alterations are reversible.
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Indium arsenide (InAs) is partially dissociated in vivo to form inorganic arsenic and indium and excreted into the urine and feces. InAs dissolves slowly over time with deposits at the site of injection. Results of this study demonstrated that the principal metabolite of arsenic in the urine of hamsters was dimethylated arsenic (DMA). Inorganic arsenic and DMA accumulated in the fur, but the concentrations of indium were very low in this matrix. Urine and feces were the principal routes of elimination from the body. Analysis of tissues for arsenic demonstrated as concentrations in the parts per billion range. Results of these studies indicate that InAs is dissociated in vivo with release of both the indium and arsenic moieties to target tissues.
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Gallium arsenide (GaAs) has been shown previously to suppress the in vivo antibody-forming cell (AFC) response to sheep erythrocytes (SRBC) when administered intratracheally at concentrations between 50 and 200 mg/kg. In the present studies, direct addition of GaAs to in vitro-generated antibody cultures resulted in dose-dependent suppression of the primary antibody response, and was only seen when GaAs was added within 36 hr following immunization. Using atomic absorption spectrophotometry on tissue samples from mice exposed to 200 mg/kg GaAs, arsenic concentrations were found to peak in the spleen at 24 hr and decline, whereas gallium concentrations continue to rise through 14 days. Concentrations of each metal in the spleen at 24 hr are comparable to the concentrations achieved for each metal when GaAs is added at 25 microM to the in vitro model system. The 24 hr time point was chosen for comparison because all in vivo-in vitro studies were conducted using spleens from mice 24 hr after GaAs exposure. NaAsO2 and Ga(NO3)3 suppressed the AFC response dose-dependently, and in a time-dependent manner similar to GaAs when added to the in vitro system. However, based on IC50 values for each salt, the role of the gallium component in the immunosuppression appears weak. Oxalic acid (OA) and meso-2,3-dimercaptosuccinic acid (DMSA), chelators of gallium and arsenic respectively, were added to cultures with GaAs to confirm that arsenic was the primary immunosuppressive component. DMSA dose-dependently blocked GaAs-induced immunosuppression in vitro, while OA had no effect. The metal-binding compounds were determined to be specific for the metals used in these studies and did not cross-react with one another. DMSA was evaluated for its ability to prevent suppression of the AFC response in splenocytes from GaAs-exposed mice and was able to block GaAs-induced suppression of the AFC response when given sc every 4 hr beginning 1 hr prior to GaAs exposure. These data indicate that the arsenic component of GaAs is the major contributor to the GaAs-induced immunosuppression and that this effect occurs within the first 36 hr of the 5-day culture period in a concentration-dependent manner.
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Acute exposure of mice to a single intratracheal dose of gallium arsenide (50, 100, and 200 mg/kg) depresses the primary IgM antibody response to the T-dependent antigen sheep red blood cells (SRBC) through alterations in the function of splenic accessory cells. To determine the mechanism by which GaAs exposure influences splenic accessory cells, the cells were isolated by adherence and their functional capability investigated 24 hr following GaAs exposure in the animal. Splenic adherent cells from GaAs-exposed mice were greatly impaired in their ability to process and present the particulate antigen SRBC to a SRBC-primed T-cell population. However, GaAs exposure did not inhibit phagocytosis of fluorescent covaspheres by these cells, nor did it inhibit in vivo phagocytosis of 51Cr-labeled SRBC, indicating that the findings reported here were not due to decreased uptake of antigen by the accessory cells. Furthermore, production of IL-1 by these cells from exposed mice was not different from control and addition of exogenous IL-1 to cultures did not reverse GaAs-induced inhibition of the primary antibody response. GaAs exposure did not affect the percentage of Ia positive macrophages (F4/80 positive cells), but the amount of cell surface IAk molecules expressed was significantly decreased as measured by flow cytometry. In contrast to the SRBC response, GaAs did not suppress the ability of adherent splenocytes to process and present the antigen pigeon cytochrome c to the helper/inducer T cell clone F1.A.2 or the antigen KLH (keyhole limpet hemocyanin) to KLH-primed T cells. Therefore, GaAs exposure interferes with the capacity of splenic macrophages to process and/or present the particulate antigen SRBC, but not the soluble protein antigens pigeon cytochrome c or KLH.
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In vivo exposure of female B6C3F1 mice to gallium arsenide (GaAs) was evaluated for its effect on the in vitro IgM antibody-forming cell (AFC) response. In vivo exposure to a single intratracheal dose of GaAs (2.5-200 mg/kg) resulted in a dose-dependent decrease in the in vitro IgM AFC response to the T-dependent antigen sheep red blood cells (SRBC) with a 97% decrease at 200 mg/kg when compared to vehicle controls. The response to the T-independent antigen DNP-Ficoll was significantly reduced at 100 and 200 mg/kg. Spleen cellularity decreased in a dose-related manner with a 54% decrease at 200 mg/kg. Enumeration of splenic subpopulations following GaAs (200 mg/kg) indicated a 58, 61, and 30% decrease in the total number of Thy 1.2 (T cells), Ig (B cells), and F4/80 (macrophages) positive cells, respectively, with no alterations in the percentages of these cells. Mitogenic responsiveness of splenocytes from GaAs-exposed mice was unaltered. To identify the splenic cell populations targeted by GaAs, the AFC response to SRBC was evaluated following cell separation/reconstitution of splenocytes from GaAs- (200 mg/kg, 24-hr exposure) and vehicle-exposed mice. Results demonstrated AFC suppression was due to functional alterations in both adherent (AD; macrophages) and nonadherent, (both T and B lymphocytes) cell populations. Further investigation focused on alterations in the AD population. Separation/reconstitution experiments demonstrated AFC suppression to SRBC was dependent on the concentration of macrophages from GaAs-exposed mice. This macrophage-mediated suppression of the in vitro AFC response could not be attributed to the presence of suppressor macrophages or release of prostaglandins.
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The semiconductor industry has been an enormous worldwide growth industry. At the heart of computer and other electronic technological advances, the environment in and around these manufacturing facilities has not been scrutinized to fully detail the health effects to the workers and the community from such exposures. Hazard identification in this industry leads to the conclusion that there are many sources of potential exposure to chemicals including arsenic, solvents, photoactive polymers and other materials. As the size of the semiconductor work force expands, the potential for adverse health effects, ranging from transient irritant symptoms to reproductive effects and cancer, must be determined and control measures instituted. Risk assessments need to be effected for areas where these facilities conduct manufacturing. The predominance of women in the manufacturing areas requires evaluating the exposures to reproductive hazards and outcomes. Arsenic exposures must also be evaluated and minimized, especially for maintenance workers; evaluation for lung and skin cancers is also appropriate.
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The effects of gallium arsenide (GaAs) exposure on immunocompetence of B6C3F1 female mice were investigated. GaAs was administered as a single intratracheal instillation at doses of 50, 100, and 200 mg/kg. Fourteen days after exposure, various cellular and humoral immune parameters were assessed. GaAs exposure increased spleen cellularity in a dose-dependent manner. However, the percentages of Thy 1.2 positive and Ig positive cells were decreased and that of F4/80 positive cells was increased dose dependently. The IgM and IgG antibody-forming cell response of the spleen to the T-dependent antigen sheep erythrocytes was reduced by 66 and 48%, respectively, at 200 mg/kg. Levels of the serum complement protein, C3, were increased by as much as 16% with no significant change in CH50 levels. The mitogenic response of splenic T cells to Con A and PHA was unaffected by GaAs, but that of B cells to LPS was increased by 52%. The delayed hypersensitivity response to keyhole limpet hemocyanin and mixed lymphocyte response were significantly reduced in a dose-dependent manner by GaAs exposure. Natural killer cell activity against the YAC-1 mouse lymphoma was enhanced in treated mice. Analysis of peritoneal exudate cells (PEC) revealed a dose-dependent decrease in number and a shift in the composition of PECs. The percentage of PEC monocytes increased from 53% of the population to 81%, while the lymphocytes decreased from 46 to 20%. The adherent PEC population demonstrated decreased phagocytosis of covaspheres and increased phagocytosis of chicken erythrocytes (CRBC). GaAs exposure had no effect on host resistance to Plasmodium yoelii or Streptococcus pneumoniae, but dose dependently increased resistance of the mouse to Listeria monocytogenes. Treated mice demonstrated a significantly decreased resistance to the B16F10 melanoma with a sevenfold increase in tumor burden at 200 mg/kg. GaAs affects both humoral and cellular immune parameters in mice and impairs the ability of the immune system to protect against B16F10 tumor challenge.
Article
Exposure to gallium arsenide (GaAs) is a potential hazard in the semiconductor industry and there is a need for specific biological indicators of exposure/toxicity for this compound. These studies examined effects of GaAs exposure on the heme biosynthetic pathway enzyme delta-aminolevulinic acid dehydratase (ALAD). Male CD rats received GaAs suspensions at doses of 50, 100, or 200 mg/kg via a single intratracheal instillation. Six days after treatment a dose-dependent inhibition of blood ALAD was observed with activity decreasing to 5% of controls at the highest dose, with a concomitant marked increase in the urinary excretion of aminolevulinic acid (ALA). Inhibition of blood ALAD following administration of GaAs was maximal (30% of control) 3 to 6 days postexposure and returned to approximately control values on day 18. Urinary excretion of ALA was maximal 3 to 6 days postexposure and recovered toward control values at 18 days. Inhibition of kidney and liver ALAD following GaAs exposure was also evident. Intratracheal instillation of silica did not alter the activity of ALAD in blood, liver, or kidney. Marked increases in lung wet weight/body weight ratios were evident in lungs of silica- and GaAs-treated rats. Histopathological changes in the lungs were characterized by multifocal granulomas following silica treatment and Type II pneumocyte hyperplasia following GaAs treatment; mild necrosis was evident in both groups. Rats treated with 100 mg/kg GaAs exhibited swelling of kidney proximal tubule mitochondria 6 days following exposure. Silica and GaAs exposure produced marked decreases in cumulative weight gain. The concentration of gallium required to achieve half-maximal inhibition of ALAD in vitro was 200-fold less in blood and 40-fold less in kidney and liver than that required for arsenite and the inhibition was partially prevented by excess zinc. These data suggest that gallium is the primary inhibitor of ALAD following dissolution of GaAs in vivo and that competition for or displacement of zinc from the enzyme active site may be involved in the mechanism of inhibition. The data also demonstrated the utility of including a particulate control group when assessing the chemical-induced toxicity of compounds administered intratracheally as particulate suspensions. Finally, measurement of heme precursors, e.g., ALA, in urine coupled with assay of red blood cell ALAD activity may be of value as an early biological indicator of GaAs exposure and/or toxicity.
Article
Gallium arsenide (GaAs) is an intermetallic compound that is recognized as a potential toxicological risk to workers occupationally exposed to its dust. Previous results have shown that rats intratracheally instilled with a fraction of GaAs particulates, characterized with a mean count diameter of 8.30 microns and a mean volume diameter of 12.67 microns, developed signs of systemic arsenic intoxication, pulmonary inflammation, and pneumocyte hyperplasia. The results of the present study confirm these findings and also show that a significantly smaller fraction of GaAs is a relatively more severe pneumotoxicant. Decreasing the particle mean count and mean volume diameter to 1.63 micron and 5.82 microns, respectively, increased the in vivo dissolution rate of GaAs, increased the severity of pulmonary lesions previously associated with GaAs exposure, and resulted in unique pathological sequelae in affected lung tissue. Pulmonary fibrosis, as indicated by analysis of lung 4-hydroxyproline content, was not considered statistically significant although histological examination of lung tissue revealed a mild fibrotic response. These results provide additional evidence that pulmonary exposure to respirable GaAs particulates is a potential health hazard in the semiconductor industry.
Article
The increasing use of gallium arsenide (GaAs) in the electronics industry has produced the need for pharmacokinetic and toxicologic data on GaAs. The disposition in male Syrian golden hamsters (n = 4) following intratracheal instillation of GaAs (mean volume diameter 5.8 micron), arsenic (III) oxide (arsenite), and arsenic (V) oxide (arsenate) at a dose of 5 mg/kg body weight was examined. Blood, kidney, liver, and lung samples were collected at 1, 2, and 4 days after administration. Excreta were collected daily. Urinary metabolite profiles were determined after separation on a mixed anion-cation-exchange column. Total As content was analyzed by direct hydride flame atomic absorption spectrophotometry after digestion. Arsenic blood levels after GaAs, arsenite, and arsenate administration were 0.185 +/- 0.041, 0.596 +/- 0.117, and 0.310 +/- 0.045 ppm, respectively, after Day 1. Arsenic blood levels after GaAs administration increased to 0.279 +/- 0.021 ppm on Day 2 indicating continued absorption while levels decreased for the arsenite and arsenate groups. At Day 1 the liver contained 0.565 +/- 0.036, 2.62 +/- 0.26, and 0.579 +/- 0.144% of the arsenic dose of GaAs, arsenite, and arsenate, respectively. The arsenite and arsenate were rapidly excreted in the urine with almost half the dose appearing after 4 days; in contrast, only about 5% of the GaAs was found at the corresponding time. Total recoveries, as arsenic equivalents, for the three compounds were between 75 and 80%. Ratios of the two major urinary metabolites (dimethylarsinic acid/total inorganic As species) were 1.41, 1.71, and 0.983 for GaAs, arsenite, and arsenate, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
This study deals with the metabolism of gallium arsenide (GaAs). GaAs was shown to be soluble in various media. Since this compound could dissolve in aqueous solvents, in vivo dissolution was investigated. Hamsters were used to study the dissolution and subsequent pharmacokinetics of any liberated arsenic species. The fecal and urinary excretion data following oral and intraperitoneal administration showed that GaAs, when administered orally, is mostly excreted in the feces but poorly in the urine, and that the compound, when administered intraperitoneally, is poorly excreted in both the feces and urine. Analysis of tissues for arsenic levels yielded concentrations in the ppb range, which further verified this fact. Most interesting was the fact that dimethylarsinic acid (DMAA) and methylarsonic acid (MAA) along with inorganic arsenic were found in the urine and tissues. GaAs was shown to dissolve in vivo and the released arsenic species were metabolized as other inorganic arsenics were found in the urine and tissues. GaAs was shown to dissolve in vivo and the released arsenic species were metabolized as other inorganic arsenic containing compounds. The low solubility and poor oral absorption may make this compound less toxic than other inorganic arsenic compounds.
Article
The relative toxicity of gallium arsenide (GaAs) and its metal oxides was assessed by intratracheally instilling particulate suspensions of GaAs (100 mg/kg), equimolar gallium as Ga2O3 (65 mg/kg), or a maximally tolerated nonlethal dose of arsenic as As2O3 (17 mg/kg). Two weeks after dosing, five rats from each group were randomly selected for the biochemical determination of lung lipid, protein, DNA, and collagen (4-hydroxyproline; 4-HP) content. The pulmonary retention of gallium and/or arsenic and the concentration of these metals in blood were also determined. Lungs from the remaining rats (n = 3) were examined histopathologically. Pulmonary exposure to Ga2O3 particulates significantly (p less than 0.05) increased the total lipid content of lungs relative to that observed in the vehicle-treated control animals. This response appeared to be associated with the pulmonary retention of gallium particulates (means = 36% of the gallium dose). In contrast, As2O3 particulates were not retained in the lung. Blood arsenic concentrations were 36 ppm which represented 20% of the total arsenic administered. Treatment with As2O3 significantly elevated lung dry weight as well as protein, DNA, and 4-HP content. These data suggest that As2O3 induced an acute fibrogenic response. The intratracheal instillation of GaAs particulates produced effects similar to those observed with the individual oxides. The total lung content of lipids, protein, and DNA was significantly elevated. These biochemical changes were accompanied by significant increases in lung dry weight and lung wet weight. Lungs from rats receiving GaAs particulates retained 44% of the dose as gallium and 28% of the dose as arsenic at the end of the 14-day study. Blood arsenic concentrations were 44 ppm (7% of the arsenic dose) while gallium was not detected in blood at this time. The primary histopathological observations 14 days after the intratracheal instillation of all metal particulates were an inflammatory response and pneumonocyte hyperplasia. The biological severity of these lesions, in descending order, was GaAs greater than As2O3 much greater than Ga2O3. It must be noted, however, that As2O3 was dosed at 0.25 X moles of GaAs.
Article
The in vitro solubilities of gallium arsenide (GaAs) and its metal oxides were arsenic(III) oxide greater than GaAs much greater than gallium(III) oxide. GaAs dissolution was also dependent upon the type and concentration of buffer anion. The amount of arsenic dissolved in 12 hr by various aqueous media was 0.2 M phosphate buffer greater than or equal to 0.1 M phosphate buffer greater than Krebs-Hensleit buffer greater than distilled H2O greater than HCl-KCl buffer. GaAs was apparently soluble under in vivo conditions. Blood arsenic concentrations in rats 14 days after intratracheal instillation of 10, 30, or 100 mg/kg GaAs were 5.5, 14.3, and 53.6 micrograms/ml, respectively; gallium was not detected at any doses. An increase in lung wet weight at 14 days was dose dependent with these organs retaining 17 to 42% of the dose as gallium or arsenic. Excretion of gallium and arsenic was limited to the feces. Urinary porphyrin concentrations and body weight, monitored as indices of toxicity, were significantly altered over the 14-day study. The analysis of porphyrins revealed that uroporphyrin replaced coproporphyrin as the primary urinary metabolite. Rats receiving 10, 100, or 1000 mg/kg GaAs po exhibited similar signs of toxicity. Blood arsenic concentrations at 14 days were 3.5, 6.8, and 17.6 micrograms/ml, respectively. Porphyria was increased, and body weight was decreased at 1000 mg/kg GaAs. These values were equivalent to those obtained with an intratracheal dose of 10 to 30 mg/kg GaAs. Our results showed that pulmonary and po exposure to GaAs resulted in systemic arsenic intoxication. The finding that urinary uroporphyrin concentrations were greater than coproporphyrin concentrations may serve as a sensitive indicator for GaAs exposure.
Article
The effects of indium and arsenic on the heme biosynthetic pathway have been well documented but the effects of indium arsenide (InAs), the next possible generation of the III-V semiconductors, are unknown. Male Syrian golden hamsters were given s.c. injections of sodium arsenite (As3+), indium chloride (In3+) or indium arsenide (InAs). Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was inhibited in all exposure groups, while hepatic ALAD activity was not significantly changed. In contrast, the activity of renal ALAD was found to be statistically decreased by As3+ at 10 days, but increased at 30 days, while In3+ and InAs inhibited this enzyme activity at all time points. In vitro studies showed that hepatic ALAD activity was more sensitive to In3+ than As3+, suggesting that the effects of InAs in vivo on this enzyme are due primarily to the In rather than the As moiety. Studies of urinary porphyrin excretion patterns in animals treated with InAs showed marked, early 2-4-fold increase in the excretion of the penta-, hexa- and heptacarboxyl porphyrin at 1-5 days which continued through day 30 of the study. In contrast, there was a slow and steady rise in the excretion of coproporphyrin I and III which reached a maximum at day 30. The results of these studies indicate that both the In and As moieties of InAs are biologically active following InAs exposure and that the enzymes in the heme pathway, such as ALAD, may have great utility as markers of exposure/toxicity for these agents.
Article
ガリウムヒ素(GaAs)は半導体素子,発光ダイオード等に幅広く利用されており,今後その需要は急速に伸びていくものと思われる.本研究ではGaAsを雄ラットの気管内に反復投与し,雄性生殖系への影響について検討を行った. 12週齢の雄のWistarラットに対して7.7 mg/kgのGaAs (NMD: 1.32μm, σg: 1.76)をリン酸緩衝液(pH 6.9)に懸濁して週2回・計16回気管内に投与した.対照群に対してはリン酸緩衝液のみを同様に投与した.投与期間終了後,ラットはエーテル麻酔下で生殺し,精巣および精巣上体の重量・精子数,異常精子の出現頻度によって, GaAsの雄性生殖系への影響について評価を行った. GaAsの投与によって精巣の重量や精子数には変化は認められなかった.しかし,精巣上体においては,精巣上体重量の減少,精巣上体体尾部における精子数の減少,および異常精子出現頻度の増加を認めた.精巣上体体尾部における精子数は対照群では167.4±21.3×106であったのに対して, GaAs群では98.6±23.8×106であり,約40%の減少が認められた.また異常精子を形態から未熟精子,奇形精子,無尾精子の三つに分類して評価すると, GaAs投与群ではそれぞれで対照群と比較して27倍, 14倍, 4倍の増加が認められた.さらに形態的に未熟な精子の増加のほとんどは, straight head型の未熟精子の増加によるものであった.以上の結果から,ラットではGaAsの気管内反復投与により精子数の減少,異常精子の増加を来たすことが確認された.今後は精巣の病理組織学的評価を行い, GaAsの雄性生殖系への影響について,より詳細な検討を行う予定である.
These studies were conducted to assess alterations in renal tubule cell gene expression following in vivo exposure to the semiconductor elements indium (In), arsenic (As) or indium arsenide (InAs). Alterations in proximal tubule cell gene expression were monitored at similar tissue concentrations of In or As at various time-points following single subcutaneous (sc) injections of In, As or InAs at 0, 10 and 30 days (In: 1.5 mg/kg; As, 3 mg/kg or 0.3 mg/k; and InAs: 1000 mg/kg). Protein synthesis as monitored by incorporation of 35S methionine was not statistically increased over the 30-day period following sc injection of As, In or InAs relative to controls. Two dimensional--SDS/polyacrylamide gel electrophoresis showed that exposure to InAs stimulated the synthesis of a number of proteins with molecular masses of < 10, 18, 28, 32, 38, 42, 58, 70, 98 KDa. Exposure to As produced an increase in the expression of thirteen gene products. Indium produced similar changes at the 10-day time-point, but increased tissue accumulation of this element at 30 days markedly suppressed the stress protein response. These data indicate that induction of these specific gene expression patterns may be useful as early indicators for assessing exposure to InAs, or inorganic As, while suppression of these responses by In suggests a compromise in this basic protective mechanism.
Article
The electronics industry is expanding the use of gallium arsenide in the production of optoelectronic devices and integrated circuits. Workers in the electronics industry using gallium arsenide are exposed to hazardous substances such as arsenic, arsine, and various acids. Arsenic requires stringent controls to minimize exposures (the current OSHA PEL for arsenic is 10 micrograms/m3 and the NIOSH REL is 2 micrograms/m3 ceiling). Inorganic arsenic is strongly implicated in respiratory tract and skin cancer. For these reasons, NIOSH researchers conducted a study of control systems for facilities using gallium arsenide. Seven walk-through surveys were performed to identify locations for detailed study which appeared to have effective controls; three facilities were chosen for in-depth evaluation. The controls were evaluated by industrial hygiene sampling. Including personal breathing zone and area air sampling for arsenic and arsine; wipe samples for arsenic also were collected. Work practices and the use of personal protective equipment were documented. This paper reports on the controls and the arsenic exposure results from the evaluation of the following gallium arsenide processes: Liquid Encapsulated Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy. Results at one plant showed that in all processes except epitaxy, average arsenic exposures were at or above the OSHA action level of 5 micrograms/m3. While cleaning the LEC crystal pullers, the average potential arsenic exposure of the cleaning operators was 100 times the OSHA PEL. At the other two plants, personal exposures for arsenic were well controlled in LEC, LEC cleaning, grinding/sawing, and epitaxy operations.
Article
Acute toxicity studies were conducted on copper gallium diselenide (CGS), copper indium diselenide (CIS), and cadmium telluride (CT), three novel compounds used in the photovoltaic and semiconductor industries. Female Sprague-Dawley rats (six rats/dose) were administered 0, 12, 25, 50, or 100 mg/kg body wt of CGS, CIS, or CT by intratracheal instillation. At 72 hr after treatment, body weight gain was significantly decreased in the 100 mg/kg CIS group and in all CT dose groups. Lung weights were increased in most chemical-treated rats, with CT causing the greatest increase. Total numbers of cells in bronchoalveolar lavage fluid (BALF) were significantly increased in treated rats and were greatest in the 100 mg/kg CIS group. Differential cell counts of BALF demonstrated a marked decrease in the percentage of alveolar macrophages and an increase in the percentage of polymorphonuclear leukocytes in all dose groups of all three chemicals. Slight to moderate increases in lactate dehydrogenase activity were observed in BALF from CGS- and CIS-treated rats; marked increases were observed in CT-treated rats. BALF protein was significantly increased in rats treated with CIS and CT. Microscopic examination revealed lymphoid hyperplasia in lungs of rats treated with all three chemicals. CT caused necrosis of the terminal bronchiolar epithelium and epithelium of the alveolar duct region with inflammation, prominent fibrin exudates, and type II cell hyperplasia. CGS and CIS also caused intraalveolar inflammation and type II cell hyperplasia, but did not cause the necrosis and fibrin exudate observed in lungs of CT-treated rats. Based on changes in lung weight, BALF indices, and histopathology, CT was the most toxic for the lung; CIS had intermediate toxicity and CGS was the least toxic. The solubilities of CGS and CIS were relatively low and similar at both pH levels and do not readily explain the observed differences in pulmonary toxicity. The solubility of CdTe was considerably greater than that of CGS and CIS and likely contributed to the greater toxicity of this compound.
Article
The testicular toxicities of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were examined by repetitive intratracheal instillation using hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) were instilled twice a week a total of 16 times and InAs (7.7 mg/kg) was instilled a total of 14 times. GaAs caused testicular spermatid retention and epididymal sperm reduction, though the degrees were less severe than those in rats shown in our previous experiment. InAs and As2O3 did not show any testicular toxicities. Serum arsenic concentration in GaAs-treated hamsters was less than half of that in As2O3-treated hamsters in which no testicular toxicities were found. Serum molar concentration of gallium was 32-times higher than that of arsenic in GaAs-treated hamsters. Therefore gallium may play a main role in the testicular toxicity of GaAs in hamsters.
Article
Indium arsenide and gallium arsenide are important new materials in the semiconductor industry due to their superior electronic properties in comparison with the older silicon-based materials. Animal experiments have shown that exposure to these compounds induces marked alterations in gene expression and immune response. Toxicity to the immune system has frequently been related to T and B cell apoptosis. In the present study we show that the semiconductor elements indium (In) and arsenic (As) are able to induce apoptosis in rat thymocytes in vitro. The results show that exposure to InCl3 (1, 10, or 100 microM) or Na AsO2 (0.01, 0.1, or 1 microM) induced DNA laddering after 6 h of incubation without compromising cell viability. These results were corroborated by flow cytometry analysis of propidium iodide-loaded cells, showing a typical high hypodiploid DNA peak in apoptotic thymocytes. Higher doses of In (1 mM) or As (10-100 microM) induced cell death by necrosis. These data indicate that In and As can induce apoptosis and necrosis in T lymphocytes in a dose-dependent manner, which may be of relevance for their immunotoxicity.
Article
Gallium arsenide (GaAs), a group III-VA intermetallic semiconductor, possesses superior electronic and optical properties and has a wide application in electronic industry. Exposure to GaAs in the semiconductor industries could be a possible occupational risk. The aim of the present study was to determine the dose-dependent effect of single oral exposure to GaAs (500, 1000, or 2000 mg/kg) on some biochemical variables in heme synthesis pathway and few selected physiological variables at d 1, 7, and 15 following administration. The results indicate that GaAs produced a significant effect on the activity of delta-aminolevulinic acid dehydratase (ALAD) in blood and heart (particularly at d 7) following exposure to 2000 mg/kg, whereas urinary delta-aminolevulinic acid (ALA) excretion was elevated only at d 7. No marked influence of GaAs on blood hemoglobin, zinc protoporphyrin, and packed cell volume was noticed. Blood glutathione (GSH) was significantly reduced at d 7, but remained unchanged at two other time intervals. On the other hand, heart GSH contents remained uninfluenced on GaAs exposure. Most of the physiological variables, viz. blood pressure, heart and respiration rate, and twitch response, remained unchanged, except for some minor alterations observed at d 7 and 15 following exposure to GaAs at a dose of 2000 mg/kg. Blood gallium concentration was not detectable in normal animals and rats exposed to 500 mg/kg GaAs. Blood arsenic concentration was, however, detectable even at the a lower dose level and increased in a dose-dependent manner. All these changes showed a recovery pattern at d 21, indicating that the alterations are reversible.
Article
Copper gallium diselenide (CGS), copper indium diselenide (CIS), and cadmium telluride (CdTe) are novel compounds used in the photovoltaic and semiconductor industries. This study was conducted to characterize the relative toxicities of these compounds and to evaluate the pulmonary absorption and distribution after intratracheal instillation. Female Sprague-Dawley rats were administered a single equimolar dose (70 mM) of CGS (21 mg/kg), CIS (24 mg/kg), CdTe (17 mg/kg), or saline by intratracheal instillation. Bronchoalveolar lavage fluid (BALF) protein, fibronectin, inflammatory cells, lung hydroxyproline, and tissue distribution were measured 1, 3, 7, 14, and 28 days after instillation. Relative lung weights were significantly increased in CIS- and CdTe-treated rats at most time points. Inflammatory lesions in the lungs consisting of an influx of macrophages, lymphocytes, and PMNs were most severe in CdTe-treated rats, intermediate in CIS-treated rats, and minimal in rats receiving CGS. Hyperplasia of alveolar type 2 cells was present in CIS- and CdTe-treated rats and was greatest in CdTe-treated rats. Pulmonary interstitial fibrosis was observed in CdTe-treated rats at all time points. All three compounds caused marked increases in total BALF cell numbers, with the greatest increase observed in CIS-treated rats. BALF protein, fibronectin, and lung hydroxyproline were significantly increased in all treated animals and were highest in CdTe-treated animals. There was no apparent pulmonary absorption or tissue distribution of CGS. Indium levels increased in extrapulmonary tissues of CIS-treated rats, although Cu and Se levels remained unchanged. CdTe was absorbed from the lung to a greater extent than CGS and CIS. Cd and Te levels decreased in the lung and increased in extrapulmonary tissues. Of these compounds CdTe presents the greatest potential health risk because it causes severe pulmonary inflammation and fibrosis and because it is readily absorbed from the lung may potentially cause extrapulmonary toxicity.
Article
Male albino rats were given a single oral dose of gallium arsenide (GaAs) (100, 200 or 500 mg/kg). Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was inhibited in all the three GaAs-exposed groups accompanied by elevated urinary excretion of ALA. A significant increase in serum aspartate aminotransferase (AST) activity, and gamma-glutamyltranspeptidase (gamma-GT) was observed. A significant increase in hepatic malondialdehyde (MDA) and a decrease in hepatic glutathione contents were also noted. Renal alkaline phosphatase activity, urinary ALA and protein excretion increased significantly on GaAs exposure. These changes were accompanied by significant alterations in almost all the immunological variables, with an increase in gallium and arsenic concentration in blood and soft tissues. While most of the above biochemical alterations were prominent at day 7 following single exposure to 200 and 500 mg/kg GaAs, most of the immunological indices altered with all the three doses and remained high even at day 21. The results suggest only a moderate effect of GaAs on renal and hepatic tissues. By contrast, immunological and haematological systems are the most vulnerable to the toxic effects of GaAs.
Article
The influence of selenium (6.3 and 12.6 micromol/kg, intraperitoneally) on the disposition of gallium and arsenic and a few gallium arsenide (GaAs) sensitive biochemical variables was studied in male rats. Concomitant administration of Se and GaAs (70 micromol/kg, orally, 5 days a week for 4 weeks) significantly prevented the accumulation of arsenic while, the gallium concentration reduced moderately in the soft organs. The biochemical (haematopoietic and liver) and immunological variables however, responded less favorably to selenium administration. Most of the protection was however observed with the dose of 12.6 micromol rather than at 6.3 micromol. The results thus suggest a few beneficial effects of selenium in preventing the appearance of signs of GaAs toxicity like preventing inhibition of blood delta-aminolevulinic acid dehydratase (ALAD), hepatic malondialdehyde (MDA) formation and the accumulation of gallium and arsenic concentration.
Article
Toxic effects of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were studied in male Syrian golden hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) particles were instilled intratracheally twice a week a total of 16 times, while InAs (7.7 mg/kg) was instilled a total of 14 times. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During the instillation period, the cumulative body weight gain of the InAs-, but not the GaAs- or As2O3-treated hamsters was suppressed significantly, when compared with the control group. Slight to severe inflammatory responses were observed in the lung for all treatment groups. The most severe inflammatory change, characterized by an accumulation of neutrophils and macrophages, exudation, thickness of the pleura and fibrotic proliferation was found in the InAs-treated hamsters. Extensive alveolar or bronchiolar cell hyperplasia with or without keratinizing squamous cell metaplasia was observed in almost all the InAs-treated hamsters. Furthermore, squamous cell metaplasia or squamous cell hyperplasia developed in some of the InAs-treated hamsters, but not in the GaAs- or As2O3-treated hamsters. Slight to mild lesions were found in the convoluted tubules of the kidney in both the GaAs and InAs groups. From the present study, the toxic potency of these particles was provisionally estimated to be in the following order: InAs > GaAs > As2O3, at the dosage level used in this study. Furthermore, there was evidence that InAs particles could induce pulmonary, renal or systemic toxicity, and as such, InAs particles may produce pulmonary precancerous change when instilled intratracheally into hamsters.
Article
Rodent bioassays have been used to assess the carcinogenicity of several inhaled, poorly soluble, nonfibrous particles that vary in toxicity and carcinogenic potency. There is substantial published information from chronic inhalation bioassays of diesel exhaust, carbon black, titanium dioxide, talc, and coal dust. This review summarizes data from studies with exposures for 2 yr or more using these 5 materials. The review has four objectives: (1) to summarize the current information available from these bioassays concerning exposure-dose-carcinogenic response in rats, (2) to summarize the pathologic and phenotypic features of the neoplastic response in rats, (3) to examine possible strain- and gender-related differences, and (4) to compare the neoplastic responses of rat to those of other species exposed to these materials.
Article
Chemical-induced carcinogenesis has been in the focus of toxicological research for many decades. However, the mechanisms leading to tumor formation are only understood with certain substances. The intake of potential carcinogens by inhalation is a major route of exposure. Chemical-induced lung tumors are the final manifestation of a multistep pathway, resulting in an imbalance between cell proliferation and cell death by apoptosis. The impact of certain confounding factors e.g. extent of inflammatory response, type of genotoxic event, antagonizing principles and genetic background are discussed in this article. Finally, methods to assess the inflammatory potential of chemicals are referred to.
Article
The effect of meso 2,3-dimercaptosuccinic acid (DMSA) and monoisoamyl DMSA (MiADMSA) on gallium arsenide (GaAs) induced liver damage was studied. The oral feeding rat model was used in this study. The animals were exposed to 10 mg/kg GaAs, orally, once daily, 5 days a week for 24 weeks and treated thereafter with single oral daily dose of either 0.3 mmol/kg DMSA or MiADMSA for two course of 5 days treatment. The animals were sacrificed thereafter. Lipid peroxidation was assessed by measuring liver thiobarbituric acid reactive substance (TBARS). Liver damage was assessed by number of biochemical variables and by light microscopy. The activity of superoxide dismutase (SOD) and delta-aminolevulinic acid dehydratase (ALAD) beside reduced glutathione (GSH) concentration was measured in blood. Exposure to GaAs produced a significant reduction in GSH while, increased the oxidized glutathione (GSSG) concentration. Hepatic glutathione peroxidase (GPx) and catalase activity increased significantly while level of serum transaminase increased moderately. Gallium arsenide exposure also produced marked hepatic histopathological lesions. Overall, treatment with MiADMSA proved to be better than DMSA in the mobilization of arsenic and in the turnover of some of the above mentioned GaAs sensitive biochemical alterations. Histopathological lesions also, responded more favorably to chelation treatment with MiADMSA than DMSA.
Article
Gallium arsenide (GaAs), a group III-VA intermetallic semiconductor, possesses superior electronic and optical properties and has a wide application in the electronics industry. Exposure to GaAs in the semiconductor industry is a potential occupational hazard because cleaning and slicing GaAs ingots to yield the desired wafer could generate GaAs particles. The ability of GaAs to induce oxidative stress has not yet been reported. The present study reports the role of oxidative stress in GaAs-induced haematological and liver disorders and its possible reversal overturn by administration of meso-2,3-dimercaptosuccinic acid (DMSA) and one of its analogue, monoisoamyl DMSA (MiADMSA), either individually or in combination with oxalic acid. While DMSA and MiADMSA are potential arsenic chelators, oxalic acid is reported to be an effective gallium chelator. Male rats were exposed to 10 mg/kg GaAs orally, 5 days a week for 8 weeks. GaAs exposure was then stopped and rats were given a 0.5 mmol/kg dose of succimers (DMSA or MiADMSA), oxalic acid or a combination of the two, intraperitoneally once daily for 5 consecutive days. We found a significant fall in blood delta-aminolevulinic acid dehydratase (ALAD) activity and blood glutathione (GSH) level, and an increased urinary excretion of delta-aminolevulinic acid (ALA) and an increased malondialdehyde (MDA) level in erythrocytes of rats exposed to GaAs. Hepatic GSH levels decreased, whereas there was an increase in GSSG and MDA levels. The results suggest a role of oxidative stress in GaAs-induced haematological and hepatic damage. Administration of DMSA and MiADMSA produced effective recovery in most of the above variables. However, a greater effectiveness of the chelation treatment (i.e. removal of both gallium and arsenic from bo