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Authors C2TN members: Rosa Marques 4* , Maria Isabel Prudêncio 4 , João Carlos Waerenborgh 6 , Bruno Vieira 6 (Post-Doc), Maria Isabel Dias 4 , Dulce Franco 4 * Email of corresponding author: [email protected] Collaborations F. Rocha 1,2 , E. Ferreira da Silva 1,2 , M. Cabral Pinto 3 , M. M. Abreu 4 1 UA | Univ.Aveiro, Aveiro, Portugal 2 GeoBioTec | Univ.Aveiro, Aveiro, Portugal 3 INIDA | Santiago, Cabo Verde 4 ISA | Inst.Sup.Agronomia, Lisboa, Portugal Keywords Cape Verde Volcanic soils Geochemical mapping Funding Nuclear methods to build geochemical maps of oceanic volcanic islands – societal benefit Challenge-based research in Cape Verde to construct an Environmental Atlas using a low sampling- density survey of topsoils of the islands (IGCP Project 259 International Geochemical Mapping, running since 2009). Motivation - Geochemical mapping of volcanic islands and characterizing naturally “contaminated” zones - Better knowledge of chemical elements behavior in semi-arid and arid surface environments, crucial to predict processes in soils worldwide due to Global Warming/Climate Change Santiago Cape Verde archipelago Brava Fogo Santiago Sal QNuclear Methods - INAA and Mössbauer Fe speciation Lower unit Middle unit Upper unit Extrusive carbonatite 57 Fe Mössbauer spectra • Fe is strongly oxidized in silicates structure and iron oxides (hematite, oxidized magnetite and maghemite); • Topsoils developed on extrusive carbonatites are clearly distinguished due to the absence of Fe 2+ in the silicate phases and predominance of low oxidized magnetite. Lower unit Middle unit Upper unit Upper unit Geochemistry - Fingerprints to trace carbonatites, which lead to potential risk zones, were identified. Sal Fogo Oxidation is a major weathering mechanism; Fe complete oxidation magnetite → maghemite → hematite Nanosized hematite is of great importance in the retention of metal(oid)s Brava Comparing total contents, aqua regia-extractable amount of chemical elements and grain size: - Total contents of Cs, As and Ga are associated with the finer soils. - Fe, Co, Mn and Sc extraction increases with the clay size proportion. Variables Variables Total contents Semi-arid to arid climate, which covers the African continent below the Sahara (Sahel area) strongly influenced by trade winds Significant accumulation of Cr, Zn, As, HREE and U in grapes “Origin of Reddening”: a ‘‘baked’’ effect by the overlying lava flow on incipient paleosol. SOCIETAL CHALLENGES : Natural Hazards and Climate Action Natural background and Identification of Risk Zones Food Security, Sustainable Agriculture and Health IMPACTS AND BENEFITS: Identification of potential mining areas Criterion based selection of soils for a sustainable agriculture Environmental Health and Public Health FUTURE GOALS: Evaluation of potential harmful chemical elements in soils, bioavailability and accumulation – transfer to food chain Studies of toxicity effects of REE, Th, U and other metal(oid)s in human tissues (e.g. hair, skin, nails, urine) Pursue the Geochemical Mapping in the other Cape Verde Islands Plants and volcanic Soil relationships of U and Th decay series radionuclides http://c2tn.tecnico.ulisboa.pt RADIATION FOR SCIENCE AND SOCIETY C 2 TN/IST acknowledges Fundação para a Ciência e a Tecnologia for financial support under the project UID/Multi/04349/2013 Research groups 1 RS | Radiopharmaceutical Sciences Group 2 RPS | Radiation Protection and Safety Group 3 REI | Radiation, Elements and Isotopes Group 4 NET | Nuclear Engineering and Techniques Group 5 QEf | f-element Chemistry Group 6 SS | Solid State Group Nuclear methods Chemical elements Thematic Strand Environment & Cultural Heritage
