Rainwater-induced leaching of selenium, arsenic and vanadium from Etnean volcanic soils

Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Mount Etna is the biggest volcano of Europe and an excellent geochemical site to study water-soil processes. Due to its volcanic activity, the rainwater has a strong compositional gradient, both in time and space. At present, the behaviour of trace elements in the soils around Mt Etna is poorly understood. To determine the influence of the rainwater pH on the potential mobilization of geogenic pollutants, batch experiments have been performed with synthetic rainwater for 25 soils collected along the flanks of the volcano. Our results show that: i) The maximum concentrations in the leaching solutions are higher for acid rain than for neutral rain (e.g. 7.7 vs 1.3 mg/L for Se). ii) With neutral rain conditions the soils upwind from the volcano have higher concentrations of Se than those downwind (up to 1.3 mg/L compared to ≤0.3 mg/L for the other samples). This trend is less clear for As and V. iii) For soils collected from 2 to 10 km downwind of the craters, Se concentrations in acid rain leachates decrease one order of magnitude with increasing distance. A similar pattern is also observed upwind from the volcano. For As and V no clear relationship between concentrations and location with respect to the volcanic craters is observed. Both i) and ii) result in a low pH dependence for samples upwind from the volcano. The biggest difference between acid and neutral leaching for As and V is observed for a sample 2 km downwind from the craters. The observed patterns are influenced by potential controlling factors, such as organic matter content, total concentrations, mineralogy, influence of the volcanic plume, etc. Our results have implications for the chemical composition of the Etnean aquifer, the only water resource to the one million inhabitants around Mt Etna, as well as for the bioavailability and potential toxicity through agricultural activities, essential to the local economy

Volcanic signature of volatile trace elements on atmospheric deposition at Mt. Etna, Italy

Volcanic volatiles and aerosol emitted into the atmosphere ultimately fall on the Earth’s surface as wet or dry deposition, and they can influence the environment and the ecosystems at local and regional scales. Therefore, atmospheric deposition plays a key-role in the geochemical cycles, redistributing volcanogenic elements to the ground. For this reason, estimating the volcanogenic trace element fluxes from the atmosphere to the surface is necessary for a better knowledge of the environmental impact of the volcanic emissions. Nevertheless, from a literature review, we have recognized the scarcity of investigation on trace element deposition in the surroundings of active volcanoes. Here, we present a chemical characterization of bulk deposition around Mt. Etna, Italy, including both major and many trace elements. Bulk depositions were collected approximately fortnightly, from April 2006 to December 2007, using a network of five rain gauges, located at various altitudes on the upper flanks around the summit craters of the volcano. For most elements highest concentrations have been found close to the emission vent, confirming the prevailing volcanic contribution to rainwater composition close to the summit craters. Comparison with contemporaneously collected plume emissions shows that deposition processes produce no evident element-to-element fractionation. By contrast, comparison with whole rock composition indicates a contrasting behaviour between volatile elements, which are highly-enriched in rainwater, and refractory elements, which have low rainwater/whole rock concentration ratios. Chemical concentrations in bulk deposition were used to estimate the deposition rates of a large suite of elements. Deposition rates for volatile trace elements like Se, As, and Cd range from 1.7, 1.2 and 0.9 µg m-2 day-1 nearby to the summit vents, to 0.5, 0.3, and 0.1 µg m-2 day-1 at the local background site on the upwind western sector

Measurement uncertainty in Total Reflection X-ray Fluorescence

© 2015 Elsevier B.V. All rights reserved. Total Reflection X-ray Fluorescence (TXRF) spectrometry is a multi-elemental technique using micro-volumes of sample. This work assessed the components contributing to the combined uncertainty budget associated with TXRF measurements using Cu and Fe concentrations in different spiked and natural water samples as an example. The results showed that an uncertainty estimation based solely on the count statistics of the analyte is not a realistic estimation of the overall uncertainty, since the depositional repeatability and the relative sensitivity between the analyte and the internal standard are important contributions to the uncertainty budget. The uncertainty on the instrumental repeatability and sensitivity factor could be estimated and as such, potentially relatively straightforward implemented in the TXRF instrument software. However, the depositional repeatability varied significantly from sample to sample and between elemental ratios and the controlling factors are not well understood. By a lack of theoretical prediction of the depositional repeatability, the uncertainty budget can be based on repeat measurements using different reflectors. A simple approach to estimate the uncertainty was presented. The measurement procedure implemented and the uncertainty estimation processes developed were validated from the agreement with results obtained by inductively coupled plasma - optical emission spectrometry (ICP-OES) and/or reference/calculated values.This work has been funded by the Spanish National Research Programme (CGL-2010-22168-C03-01).Peer Reviewe

Online Preconcentration-IC-ICP-MS for Selenium Quantification and Speciation at Ultratraces

Selenium (Se) is of key importance to human health with a very narrow concentration range of optimal dietary intake. Due to the inherent analytical challenge linked with the low natural abundance, information on precise and accurate Se speciation in deficient environments is hardly existent. This study presents a novel approach to determine Se species-specifically at ultratraces, by online coupling of a preconcentration (trap) column to an ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) system. It is demonstrated that with this robust and work/time efficient method, the predominant selenium oxyanions, selenite (SeIV) and selenate (SeVI), can be quantified down to 7.3 and 8.3 picogram total Se, respectively, in an overall analytical time of 420 s, only. The applicability for environmental samples was proven on pristine volcanic ashes collected from seven different volcanoes. The high sensitivity of the novel approach allowed to determine speciation in samples that were strongly depleted in total selenium

Potential for pharmacist prescribing in primary care:A Dutch citizen perspective

Background: Medication prescribing by pharmacists is a task shifting approach to help ensure quality and accessibility of healthcare. In many countries, like the Netherlands, pharmacist prescribing is not legally ensured, and it is unknown what citizens think of its potential introduction. Objective: To investigate citizen perspectives on the potential role of pharmacists in prescribing in primary care. Methods: A Citizen Platform with citizens (&gt;18 years) from the Netherlands was conducted in October 2022. This consisted of a one-day program in which the participants were engaged in interactive assignments and received expert presentations to foster the development of informed opinions. In the final assignment, 3 participant groups designed their ideal future scenario including preconditions regarding the role of the pharmacist in prescribing in primary care. All assignments were recorded, and notes were taken. The researchers then consolidated the 3 scenarios into one version and categorized the preconditions. The Citizen Platform results were summarized and subsequently discussed in 2 online focus groups with other citizens in February 2023 to investigate the perspectives of less informed citizens. Focus group discussions were audio-recorded, transcribed, and thematically analyzed. Results: The Citizen Platform (n = 10) resulted in a shared scenario involving a primary care center where general practitioners (GPs) pharmacists and other healthcare professionals collaborate as a team. In this scenario, pharmacists can modify treatment in certain chronic diseases, manage minor ailments and support GPs with the care for patients with complex needs. Preconditions needed to realize this scenario include having shared medical records, the GP retaining the overview of the care for the patient and additional training for pharmacists. The focus groups (n = 6, in total) yielded 5 themes which acknowledge potential pharmacist prescribing but depict a more skeptical view towards pharmacist prescribing and include several concerns, for example pharmacists' potential conflict of interest. Conclusions: Citizens that are informed about opportunities for pharmacy prescribing are capable of sketching potential scenarios for pharmacist prescribing in a collaborative primary care context. Less informed citizens seem more skeptical towards pharmacist prescribing.</p

Study of selenium sorption processes in volcanic ash using Total Reflection X-ray Fluorescence (TXRF)

Selenium (Se) cycling around volcanoes has implications for human health given the high population density close to volcanoes and the narrow range between essential and toxic Se intake. To study the Se mobility dur- ing interaction between volcanic derived acid rain and volcanic ash, new analytical approaches are required. This paper explores the Total Reflection X-Ray Fluorescence (TXRF) for Se determination using sorption pro- cesses on volcanic ash as a geochemical application. Our experiments reveal the importance of the anion con- tent of the rainwater for Se mobility in volcanic ash samples. Desorption studies of a weathered volcanic soil using the application of a dispersive liquid-liquid microextraction procedure (DLLME) to isolate Se prior to TXRF analysis (LOD 0.7μg/L) revealed much higher level of released Se in sulfuric acid rain compared to hydrochloric acid rain. Additionally, the dominance of selenate in the leaching solution suggests adsorption competition with sulfate as a Se release mechanism. Kinetic adsorption experiments using direct TXRF with as little as 10μL solution (LOD 0.4–8μg/L depending on the sample characteristics) showed that the an- ions present play a key role in the selenite adsorption on volcanic ash by competitive behavior and/or changes in the pH conditions promoted by glass dissolution processes. Our experiments show the high po- tential of TXRF in such applications. Similarly, TXRF can be used as an analytical tool to study the mobility of trace elements in other geochemical studiesThisworkwassupportedbytheEuropeanCommissionSixthFrame-work Programme (2002–2006) Research Training Network AquaTRAIN(ContractNo.MRTN-CT-2006-035420),theSpanish“Consolider Ingenio2010”Program (Project ref. SD2006-00044), the Spanish National Research Program (Project ref. CGL2007-66861-C4) and the proposer Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis (Project ref. ANNA_TA_UC7_RP003)Peer Reviewe

Flow injection analysis as a tool for enhancing oceanographic nutrient measurements: A review

Macronutrient elements (C, N and P) and micronutrient elements (Fe, Co, Cu, Zn and Mn) are widely measured in their various physico-chemical forms in open ocean, shelf sea, coastal and estuarine waters. These measurements help to elucidate the biogeochemical cycling of these elements in marine waters and highlight the ecological and socio-economic importance of the oceans. Due to the dynamic nature of marine waters in terms of chemical, biological and physical processes, it is advantageous to make these measurements in situ and in this regard flow injection analysis (FIA) provides a suitable shipboard platform. This review, therefore, discusses the role of FIA in the determination of macro-and micro-nutrient elements, with an emphasis on manifold design and detection strategies for the reliable shipboard determination of specific nutrient species. The application of various FIA manifolds to oceanographic nutrient determinations is discussed, with an emphasis on sensitivity, selectivity, high throughput analysis and suitability for underway analysis and depth profiles. Strategies for enhancing sensitivity and minimizing matrix effects, e.g. refractive index (schlieren) effects and the important role of uncertainty budgets in underpinning method validation and data quality are discussed in some detail