AuthorsC2TN members: Rosa Marques4*, Maria Isabel Prudêncio4,
João Carlos Waerenborgh6, Bruno Vieira6 (Post-Doc), Maria Isabel
Dias4, Dulce Franco4
* Email of corresponding author:
[email protected]
CollaborationsF. Rocha1,2, E. Ferreira da Silva1,2, M. Cabral
Pinto3, M. M. Abreu4
1 UA | Univ.Aveiro, Aveiro, Portugal2 GeoBioTec | Univ.Aveiro,
Aveiro, Portugal3 INIDA | Santiago, Cabo Verde4 ISA |
Inst.Sup.Agronomia, Lisboa, Portugal
KeywordsCape VerdeVolcanic soilsGeochemical 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
BravaFogo
Santiago
Sal
QNuclear Methods - INAA and Mössbauer
Fe speciation
Lower unit
Middle unit
Upper unit
Extrusive carbonatite
57Fe Mössbauer spectra
• Fe is strongly oxidized in silicates structure and iron
oxides(hematite, oxidized magnetite and maghemite);• Topsoils
developed on extrusive carbonatites are clearlydistinguished due to
the absence of Fe2+ in the silicate phasesand predominance of low
oxidized magnetite.
Lower unit
Middle unit
Upper unit
Upper unit
Geochemistry
- Fingerprints to trace carbonatites, which lead to
potentialrisk 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
chemicalelements 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 Africancontinent
below the Sahara(Sahel area) stronglyinfluenced by trade winds
Significant accumulation of Cr,Zn, As, HREE and U in grapes
“Origin of Reddening”:a ‘‘baked’’ effect bythe overlying lava
flowon 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
inhuman 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
seriesradionuclides
http://c2tn.tecnico.ulisboa.ptRADIATION FOR SCIENCE AND SOCIETY
C
2TN/IST acknowledgesFundação para a Ciência e a Tecnologia
for
financial support under the projectUID/Multi/04349/2013
Research groups1 RS | Radiopharmaceutical Sciences Group2 RPS |
Radiation Protection and Safety Group3 REI | Radiation, Elements
and Isotopes Group4 NET | Nuclear Engineering and Techniques Group5
QEf | f-element Chemistry Group6 SS | Solid State Group
Nuclear methodsChemical elements
Thematic StrandEnvironment & Cultural Heritage
