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| Titel |
Evaluation of risks of groundwater quality alteration in Recife urban area (Pernambuco, Brazil) using a multi-isotopic approach. |
| VerfasserIn |
Bertrand Guillaume, Ricardo Hirata, Veridiana Martins, Jonathan Batista, Reginaldo Bertolo, Jeane-Glaucia Santos, Suzanna Montenegro, Lise Cary, Emmanuelle Pételet-Giraud, Hélène Pauwels, Géraldine Picot, Gilles Braibant, Eliot Chatton, Luc Aquilina, Thierry Labasque, Rebecca Hochreutener, Axel Aurouet, Melissa Franzen |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107736
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| Publikation (Nr.) |
 EGU/EGU2015-7449.pdf |
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| Zusammenfassung |
| The Recife Metropolitan Region (RMR) is a heavily urbanized area located in a estuary zone
and over a multi-layered sedimentary system on the Brazilian Atlantic coast. In a context of
increasing land use pressures, involving aquifer overexploitation and surface water
contamination, and repeated droughts, the identification of groundwater quality risks
in RMR is a necessary management requirement. In this perspective, this work
focused on the two shallow aquifer systems, named Boa Viagem and Barreiras
aquifers, located at the interface between the city (the consumers) and the deeper
semi-confined Cretaceous Cabo and Beberibe aquifers. The Holocenic Boa Viagem
and Tertiary Barreiras formations conform unconfined sedimentary aquifers, with
no more than 80 m of thickness. Cabo is the most important groundwater body
for Recife private complementary water supply and it has experienced an intense
exploitation in the last three decades. In contrast, Boa Viagem and Barreiras aquifers
are more restrictively used, but it is important to understand their water quality
degradation,because of hydraulic connections with deeper aquifers, mainly in the littoral
part of Recife, where hydraulic potentiometric head of the Cabo aquifer is 60 m
below sea water level in some places, with conditions for recharge from shallower
aquifers. Through a multi-isotopic characterization (87Sr/86Sr, δ11B, δ18O-SO4,
δ34S-SO4) of sampling of 19 wells and 3 surface waters, carried out during two field
campaigns with additional geochemical parameters (major ions, noble and major
gases, CFC´ s and SF6), the spatio-temporal variability of groundwater quality was
investigated. The detection of CFC´ s, implying a modern recharge component,
highlighted the vulnerability of Boa Viagem and Barreiras to surface contaminations. The
increasing mineralization and decreasing 87Sr/86Sr from the inland sector wells to
the wells located close to the coast or estuary, with higher well and population
densities, were attributed to water-rock interactions along the natural or human-induced
potentiometric gradients. Along with this trend appeared an environmental pressure gradient,
highlighted by δ11B related to sewage or surface channel networks. These sources are
purveyors of chloride, nitrate and sulfate, which are found in varying amounts (13,6<
[Cl] |
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