Although there are arsenic contaminations of anthropogenic origin (mining, wood preservatives,…) the main causes are natural and motivated by the dissolution of minerals in surface or underground waters. Arsenic is present in natural waters either in its reduced state As(III) or in the oxidized form As(V), both toxic. Toxicity depends upon the oxidation state and, in general terms, As(III) is 60 times more toxic than As(V). Acute poisoning occurs after ingestion higher than 100 mg, while the chronic poisoning occurs after the ingestion of small quantities during a long period and the effects become visible after 5 years. The existence of As in drinking water can originate the endemic regional chronic hydroarsenicosis (ERCA) which shows as melanosis, keratosis degenerating into various types of cancer. European Union has recently lowered the permissible maximum concentration for drinking water from 0.05 mg/L to 0.01 mg/L. The average crustal abundance of arsenic is 1.5 mg/kg, being the composition of natural As minerals the following: 60% are arsenates, 20% sulfides and sufosalts, and the remaining 20% are arsenides, arsenites, oxides, alloys and polymorphs of elemental arsenic. Concentrations of As in natural waters are highly dependent on the existence of arsenic sources and the local geochemical conditions. There are areas with very high concentrations in As in Bangladesh, India, China, Taiwan, Argentina, Chile, El Salvador, México, Nicaragua and Peru. The problem is also relevant in Spain (Catalonian Pyrenees, Valladolid, Madrid, Segovia, etc.) and also in North and Central Portugal. A data base concerning Arsenic concentrations in Portuguese groundwaters was built for this project. A monography was published regarding the concentration of As in Iberian America, Portugal and Spain. You may load it here - Monografia 1. Nowadays chemical analysis can be performed by the application of improved analytical methods such as inductively coupled plasma-mass spectrometry (HG-ICP-MS), inductively coupled plasma-atomic emission spectrometry (HG-ICP-AES), and hydride generation-atomic fluorescence spectrometry (HG-AFS). We propose in this project to develop the voltametric techniques using the hanging mercury drop electrode (HMDE) which are specially adequate for the ionic speciation in natural and groundwater matrices. This methodology has a very low cost in terms of the necessary instruments when compared to the methods mentioned above and allows the direct speciation of As without any sophisticated sample treatment (allowing to keep the original As(III) to As(V) ratio without perceptible changes). It is a method appropriated to be applied in areas and laboratories with lower economic capacity; it can be easily taught and later used on an everyday base by technicians with average qualifications. The limits of detection are sufficiently low to match the objectives of this project. A monography was published regarding the chemical analysis of As in waters and soils. You may load it here - Monogradfia 2. There are three primary categories of available treatment processes: - Sorption Treatment Processes - Ion Exchange - Activated Alumina - Iron Based Sorbents - Membrane Treatment Processes - Reverse Osmosis - Precipitation/Filtration Processes - Enhanced Conventional Gravity Coagulation/Filtration - Coagulation-Assisted Microfiltration (CMF) - Coagulation-Assisted Direct Filtration (CADF) - Oxidation/Filtration - Enhanced Lime Softening Activated alumina is expensive and needs a pH correction and specialized staff . The coagulation-precipitation processes also need previous pH correction and the limit concentration of 0,01 mg/L is difficult to attain. The ion exchange resins need important investments and its applicability depends upon the competition with other anions present in the water. The reverse osmosis allows the simultaneous removal of other ions but has extremely high costs. We intend to research emerging economic technologies – specially the usage of granular iron hydroxides and hybrid sorbents - generally designated by Iron Based Sorbents (IBS). The research will focus on the usage of multifunctional permeable reactive barriers (MPRB) based on IBS and comprehending a two stage treatment: the previous oxidation of As and its in-situ fixation by IBS. The barriers to be considered will be of the funnel and gate type. The active sorbent will fill up the gate. As the reaction is irreversible the gates must be easily movable for substitution. It is aimed to reach an economic technology which can be adapted to small communities or to isolated populations. A monography was published regarding the treatment of As contaminations. You may load it here - Monografia 3. PUBLICAÇÕES CAPÍTULOS DE LIVROS Jordi Cama, Miquel Rovira, Paula Ávila, María Rosario Pereira, María Pilar Asta, Fidel Grandia, Xaviermartínez-Lladó Y Ester Álvarez-Ayuso, “Distribución de arsénico en la región Ibérica”, IN “IBEROARSEN Distribución del arsénico en las regiones Ibérica e Iberoamericana”, Editado por CYTED, 2008 [*.pdf] Maria Adelaide Alves Ferreira, “Técnicas electroquímicas para la determinación y especiación de arsénico en aguas”, Capítulo 10 da Monografia “Metodologías Analíticas para la Determinación y Especiación de Arsénico na Aguas y Suelos”, Pags 185 a 210, Editores M.I. Litter, M.A. Armienta, S.S. Farías, Editado por Cyted, Outubro 2009. [*.pdf] José Luis Cortina, António M.A. Fiúza, Aurora Silva Y Marta I. Litter, ”Tecnologías de tratamiento in-situ de aguas subterrâneas”, Capítulo 7 da monografia “Tecnologías Económicas Para El Abatimiento de Arsénico En Aguas”, Rede Cyted; Editores M.I. Litter, Editado por Cyted, [*.pdf] M.L. Dinis, A. Fiúza, “Exposure Assessment to Heavy Metals in the Environment. Measures to Eliminate or Reduce the Exposure to Critical Receptors”, Maria De Lurdes Dinis and António Fiúza, NATO Science for Peace and Security Series C: Environmental Security, 1, Volume 1, Environmental Heavy Metal Pollution and Effects on Child Mental Development, Pages 27-50 [.pdf]
M. L. Dinis, A. Fiúza, “Methodology for Exposure and Risk Assessment in Complex Environmental Pollution Situations”, 21 pgs, in “Exposure and Risk Assessment of Chemical Pollution - Contemporary Methodology”, Series: NATO Science for Peace and Security, Series C: Environmental Security, Simeonov, Lubomir I.; Hassanien, Mahmoud A. (Eds.), 2009, XXVII, 526 p., Hardcover, ISBN: 978-90-481-2333-9¸ ISI Web of Knowledge: References: 21, 2008 [abstract versão pdf] M. L. Dinis, A. Fiúza, “Modelling Multimedia Pollution for Environmental Exposure”, 22 pgs, in “Exposure and Risk Assessment of Chemical Pollution - Contemporary Methodology”, Series: NATO Science for Peace and Security, Series C: Environmental Security, Simeonov, Lubomir I.; Hassanien, Mahmoud A. (Eds.), 2009, XXVII, 526 p., Hardcover, ISBN: 978-90-481-2333-9, ISI Web of Knowledge: References: 11, 2008. [abstract versão pdf] ARTIGOS EM REVISTAS CIENTÍFICAS COM AVALIAÇÃO António Fiúza, Aurora Futuro, Aurora Silva, Adelaide Ferreira, Fernanda Guimarães, "IN-SITU REMOVAL OF ARSENIC FROM GROUNDWATER USING PERMEABLE REACTIVE BARRIERS WITH IRON BASED SORBENTS",submitted to "Journal of Contaminant Hydrology, August 2011. [.pdf] António Fiúza, Aurora Futuro, “Methodology for designing a Permeable Reactive Barrier based on IBS for the mitigation of Arsenic in Groundwaters” (em preparação) COMUNICAÇÕES EM CONGRESSOS INTERNACIONAIS Aurora Silva, Adelaide Ferreira , Paula Freire Ávila, Cristina Delerue-Matos and António Fiúza, “Arsenic leaching in the tailing materials of Vale das Gatas abandoned mine (Northern Portugal) – a case study”, Arsenic in the Environment, 2nd International Conference, Valencia 21-23 May, 2008 [versão pdf] Aurora Silva, Olga Freitas, Sónia Figueiredo, Bie Vandervliet, Adelaide Ferreira, and António Fiúza, “Arsenic Removal Using Synthetic Adsorbents: Kinetics, Equilibrium and Column Study”, 12th EuCheMS International Conference on Chemistry and the Environment, 7 June 2009, Stockholm, Sweden, 2009 [versão pdf] A. Silva, O. Freitas, S. Figueiredo, I. Azevedo, A. Ferreira, A. Fiúza, “Operating Conditions for the treatment of groundwater contaminated by arsenic using iron oxides/hydroxides”, 19th International Congress of Chemical and Process Engineering CHISA 2010 and the 7th European Congress of Chemical Engineering ECCE, Praga, 2010 [versão pdf] António Fiúza, Aurora Silva, “In-Situ Technologies For Arsenic Removal: A Critical Review”, Congresso Cyted “Tecnologías económicas para el abatimiento de arsénico en aguas”, Montevideo, Uruguay, Outubro 2009, [versão pdf] Aurora Futuro, António Fiúza, “Distribuição e Comportamento do Arsénio em Ambientes Naturais”, 6º Congresso Luso-Moçambicano de Engenharia, Agosto 2011. [versão pdf] António Fiúza, Aurora Silva, Aurora Futuro, “Tratamento de Água Subterrânea Contaminada com Arsénio Utilizando Barreiras Reactivas Permeáveis”, 6º Congresso Luso-Moçambicano de Engenharia, Agosto 2011. [versão pdf]
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