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- Metal(loids) bioaccessibility in road dust from the surrounding villages of an active minePublication . Candeias, Carla; Ávila, Paula Freire; Silva, Ferreira Da; Rocha, FernandoABSTRACT: Human activities, in general, cause a significant impact on the environment and human health. The present study aims to characterize the road dust of villages located near an active mine and to assess metal(loids) bioaccessible fractions. From the collected road dust samples (<250 µm fraction), the pseudo total, gastric (G) and gastrointestinal (GI) phase (UBM assay) concentrations, mineralogical composition, enrichment factor (EF), and risk for humans were determined. The obtained results revealed that arsenic represents the highest risk to humans, with mean pseudototal values higher than the maximum reference value range. The enrichment factor pointed to As as having significant to very high enrichment in all of the villages. In addition, Cd presented the maximum EF values in all of the villages, and was thus classified as having a very high enrichment. Particles enriched in As, Ca, Fe, Cu, Al, and Ti were identified by SEM-EDS in weathered agglomerates, and were linked to mine wastes and long-distance transport through both wind and/or traffic. The arsenic bioaccessibility fraction (%BAF) presented low values in the studied samples, possibly because of the low complex solubility of Fe with adsorbed As, limiting the release of arsenic and reducing its bioaccessibility. The concentrations of bioaccessible Cd for the G and GI phases were within the reference range, while for Cu, they were above and for Pb they were lower than the reference value range. The results show that the pseudototal fraction risk is overestimated when compared with BAF%; nevertheless, the total G and GI risks were above the carcinogenic target risk (1 × 10−6) in most of the samples. The carcinogenic risk of the bioaccessible contaminants showed that As represented the higher risk for developing cancer over a lifetime, with ingestion being the main risk route.
- NEWS4CSP Project: New coatings approaches to protect metallic materials from heat transfer fluids [Poster]Publication . Cunha Diamantino, Teresa; Pedrosa, Fátima; Paiva Luís, Teresa; Ferreira da Silva, Eduardo; Gonçalves, Francisco; Monteiro, Renato; Cardoso, João
- NEWS4CSP Project: New Coatings Approaches to Protect Metallic Materials From Heat Transfer FluidsPublication . Cunha Diamantino, Teresa; Pedrosa, Fátima; Paiva Luís, Teresa; Ferreira da Silva, Eduardo; Gonçalves, Francisco; Monteiro, Renato; Cardoso, JoãoABSTRACT: The efficiency of Concentrated Solar Power technologies increases with the opera-tion temperature of the power block, which can be achieved using advanced power cycles operating at temperatures ≥650°C. Molten Salt (MS) based HTF have been facing critical chal-lenging issues of severe corrosion and lower specific heat capacity. This paper aims to present the NEWS4CSP project to the CSP scientific community, highlighting the main concepts being pursued and the preliminary results obtained regarding the application of new coatings to in-crease the anticorrosive protection of structural materials in contact with MS. Two different types of powder coatings (nickel and cobalt alloys) were applied to AISI 430 stainless steel using two coating technologies: High Velocity Oxy-Fuel (HVOF) and Laser Cladding (LC). LC proved to be the most suitable technique of these two coating application technologies. The Co-Cr coating alloy showed good anticorrosive behaviour even after 3000 h of testing. The obtained results are very promising, nevertheless, more studies are needed to optimise its application by LC. These include optimizing the thickness and chemical composition, as well as gaining a deeper understanding of the degradation mechanisms and whether this behaviour is maintained over longer periods.