In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and ...other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic substances.
•We analyzed Myanmar ground and surface waters for multiple inorganic contaminants.•Arsenic, manganese, fluoride, iron, or uranium exceeded safe levels in most wells.•Most wells contained more than one contaminant above health-based reference values.•Arsenic was positively and uranium negatively correlated with iron and manganese.•Mitigation, including testing and treatment, must address multiple contaminants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The absence of contaminants in the hydrogen delivered at the hydrogen refuelling station is critical to ensure the length life of FCEV. Hydrogen quality has to be ensured according to the two ...international standards ISO 14687–2:2012 and ISO/DIS 19880-8. Amount fraction of contaminants from the two hydrogen production processes steam methane reforming and PEM water electrolyser is not clearly documented. Twenty five different hydrogen samples were taken and analysed for all contaminants listed in ISO 14687-2. The first results of hydrogen quality from production processes: PEM water electrolysis with TSA and SMR with PSA are presented. The results on more than 16 different plants or occasions demonstrated that in all cases the 13 compounds listed in ISO 14687 were below the threshold of the international standards. Several contaminated hydrogen samples demonstrated the needs for validated and standardised sampling system and procedure. The results validated the probability of contaminants presence proposed in ISO/DIS 19880-8. It will support the implementation of ISO/DIS 19880-8 and the development of hydrogen quality control monitoring plan. It is recommended to extend the study to other production method (i.e. alkaline electrolysis), the HRS supply chain (i.e. compressor) to support the technology growth.
•No contaminants above ISO 14687-2 threshold in H2 from SMR with PSA.•No contaminants above ISO 14687-2 threshold in H2 from PEMW with TSA.•Impact of TSA on contaminants from PEMW electrolyser.•Sampling contamination may lead to false positive.•Probability of contaminants presence in line with real hydrogen samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The deployment of hydrogen fuel cell electric vehicles (FCEVs) is critical to achieve zero emissions. A key parameter influencing FCEV performance and durability is hydrogen fuel quality. The real ...impact of contaminants on FCEV performance is not well understood and requires reliable measurements from real-life events (e.g., hydrogen fuel in poor-performing FCEVs) and controlled studies on the impact of synthetic hydrogen fuel on FCEV performance. This paper presents a novel methodology to flow traceable hydrogen synthetic fuel directly into the FCEV tank. Four different synthetic fuels containing N2 (90–200 µmol/mol), CO (0.14–5 µmol/mol), and H2S (4–11 nmol/mol) were supplied to an FCEV and subsequently sampled and analyzed. The synthetic fuels containing known contaminants powered the FCEV and provided real-life performance testing of the fuel cell system. The results showed, for the first time, that synthetic hydrogen fuel can be used in FCEVs without the requirement of a large infrastructure. In addition, this study carried out a traceable H2 contamination impact study with an FCEV. The impact of CO and H2S at ISO 14687:2019 threshold levels on FCEV performance showed that small exceedances of the threshold levels had a significant impact, even for short exposures. The methodology proposed can be deployed to evaluate the composition of any hydrogen fuel.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
As part of FCH-JU funded HyCoRA project running from 2014 to 2017, 28 gaseous and 13 particulate samples were collected from hydrogen refueling stations in Europe. Samples were collected with ...commercial sampling instruments and analysis performed in compliance with prevailing fuel quality standards. Sampling was conducted with focus on diversity in feedstock as well as commissioning date of the HRS. Results indicate that the strategy for sampling was good. No evidence of impurity cross-over was observed. Parallel samples collected indicate some variation in analytical results. It was however found that fuel quality was generally good. Fourteen analytical results were in violation with the fuel tolerance limits. Therefore, eight or 29% of the samples were in violation with the fuel quality requirements. Nitrogen, oxygen and organics were the predominant impurities quantified. Particulate impurities were found to be within fuel quality specifications. No correlation between fuel quality and hydrogen feedstock or HRS commissioning date was found. Nitrogen to oxygen ratios gave no indication of samples being contaminated by air. A comparison of analytical results between two different laboratories were conducted. Some difference in analytical results were observed.
In 2013, NPL, SUERC and Cranfield University published an estimate for the Boltzmann constant (de Podesta et al 2013 Metrologia 50 354-76) based on a measurement of the limiting low-pressure speed of ...sound in argon gas. Subsequently, an extensive investigation by Yang et al (2015 Metrologia 52 S394-409) revealed that there was likely to have been an error in the estimate of the molar mass of the argon used in the experiment. Responding to Yang et al (2015 Metrologia 52 S394-409), de Podesta et al revised their estimate of the molar mass (de Podesta et al 2015 Metrologia 52 S353-63). The shift in the estimated molar mass, and of the estimate of kB, was large: −2.7 parts in 106, nearly four times the original uncertainty estimate. The work described here was undertaken to understand the cause of this shift and our conclusion is that the original samples were probably contaminated with argon from atmospheric air. In this work we have repeated the measurement reported in de Podesta et al (2013 Metrologia 50 354-76) on the same gas sample that was examined in Yang et al (2015 Metrologia 52 S394-409) and de Podesta et al (2015 Metrologia 52 S353-63). However in this work we have used a different technique for sampling the gas that has allowed us to eliminate the possibility of contamination of the argon samples. We have repeated the sampling procedure three times, and examined samples on two mass spectrometers. This procedure confirms the isotopic ratio estimates of Yang et al (2015 Metrologia 52 S394-409) but with lower uncertainty, particularly in the relative abundance ratio R38:36. Our new estimate of the molar mass of the argon used in Isotherm 5 in de Podesta et al (2013 Metrologia 50 354-76) is 39.947 727(15) g mol−1 which differs by +0.50 parts in 106 from the estimate 39.947 707(28) g mol−1 made in de Podesta et al (2015 Metrologia 52 S353-63). This new estimate of the molar mass leads to a revised estimate of the Boltzmann constant of kB = 1.380 648 60 (97) × 10−23 J K−1 which differs from the 2014 CODATA value by +0.05 parts in 106.
Gaseous hydrogen for fuel cell electric vehicles must meet quality standards such as ISO 14687:2019 which contains maximal control thresholds for several impurities which could damage the fuel cells ...or the infrastructure. A review of analytical techniques for impurities analysis has already been carried out by Murugan et al. in 2014. Similarly, this document intends to review the sampling of hydrogen and the available analytical methods, together with a survey of laboratories performing the analysis of hydrogen about the techniques being used. Most impurities are addressed, however some of them are challenging, especially the halogenated compounds since only some halogenated compounds are covered, not all of them. The analysis of impurities following ISO 14687:2019 remains expensive and complex, enhancing the need for further research in this area. Novel and promising analyzers have been developed which need to be validated according to ISO 21087:2019 requirements.
Impurities in hydrogen can have a detrimental effect on the performance of polymer electrolyte membrane fuel cells (PEMFCs) used in automotive applications. However, the establishment of reliable ...threshold limits for each impurity is hampered by a lack of information on the distribution and speciation of impurities within the cell, including the impact of internal reactions and gas crossover. Here we describe a novel operando method for detailed investigation of the impact of impurities on a single cell PEMFC, using a combination of isotopic labelling and measurement of gas composition at the anode exhaust via Gas Chromatography – Methaniser with Flame Ionisation Detector (GC-Methaniser-FID) and Selected Ion Flow Tube – Mass Spectrometry (SIFT-MS). We demonstrate the utility of this approach in the study of the impact of internal air bleed on carbon monoxide (CO) poisoning, enabling quantification of the surface coverage of CO on the anode catalyst as a function of cathode back-pressure. This technique shows great promise as a diagnostic tool for the investigation of the impact of a wide range of impurities at stack level (e.g. hydrocarbons, ammonia, halogenated compounds).
•Development of analytical method to monitor the composition of PEMFC anode gas.•Demonstration of use of isotopic labelling to separate effects of different processes.•Quantification of adsorbed CO surface coverage at anode of operating PEMFC.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Impurities in carbon dioxide can affect several aspects of the carbon capture and storage process, including storage capacity, rock erosion, accuracy of flow meters, and toxicity of potential leaks. ...There is an industry need for guidance on performing purity analysis before carbon dioxide is transported and stored. This paper reviews selected reports that specifically provide threshold amount fraction limits for impurities in carbon dioxide for the purpose of transport and storage, with rationales for these limits. A carbon dioxide purity specification is provided (including threshold amount fractions of impurities) on the basis of the findings, as well as recommendations on further work required to develop a suitable gas metrology infrastructure to support these measurements including primary reference materials, sampling methods, and instruments for performing purity analysis. These recommendations provide important guidance to operators and gas analysis laboratories for performing quality assurance.
Identification of chemical species at a subcellular level is a key to understand the mechanisms involved in the biology of chemical elements. When performed with a microbeam, X-ray absorption ...near-edge structure (micro-XANES) enables the direct speciation analysis of oxidation states in subcellular compartments avoiding cell fractionation and other preparation steps that might modify the chemical species. Here we report the principal characteristics in terms of spatial resolution, detection limit, reproducibility, and repeatability of a micro-XANES experimental setup based on Kirkpatrick−Baez X-ray focusing optics that maintains high flux of incoming radiation (>1011 photons/s) at micrometric spatial resolution (1.5 × 4.0 μm2). Applications and limitations of this setup are illustrated by examples of iron and arsenic absorption spectra obtained from the cytosol, nucleus, and mitochondrial network of cultured cells. A better repeatability and sensitivity with no oxidation state modification and minimal beam damage is achieved when cells are analyzed in a frozen hydrated state, as compared to freeze-dried cells. This original experimental setup can now be applied for the direct speciation analysis of most trace elements at the subcellular level.
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IJS, KILJ, NUK, PNG, UL, UM
•Two sampling systems for H2 fuel quality at 70 MPa were compared.•Equivalence of two sampling systems for H2 sampling at hydrogen refuelling stations.•NPL and Air Liquide analytical laboratory agree ...on H2 fuel quality analysis.•Representative sampling of hydrogen is influenced by maintenance situation.•Interlaboratory comparison is critical to ensure H2 fuel quality accuracy.
Fuel cell electric vehicles are getting deployed exponentially in Europe. Hydrogen fuel quality regulations are getting into place in order to protect customers and ensure end-users satisfactory experiences. It became critical to have the capability to sample and analyse accurately hydrogen fuel delivered by hydrogen refuelling stations in Europe. This study presents two separate comparisons: the first bilateral comparison between two sampling systems (H2 Qualitizer) and (“H2 Sampling System” of Air Liquide) and the interlaboratory comparison between NPL and Air Liquide on hydrogen fuel quality testing according to EN 17124. The two sampling systems showed equivalent results for all contaminants for sampling at 70 MPa hydrogen refuelling stations. The two laboratories showed good agreement at 95% confidence level. Even if the study is limited due to the low number of samples, it demonstrates the equivalence of two sampling strategies and the ability of two laboratories to perform accurate measurement of hydrogen fuel quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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