A Multi-isotopic approach to investigate the influence of land use on nitrate removal in a highly saline lake-aquifer system
| Autor: | David Sanz, Juan José Gómez-Alday, Neus Otero, Albert Soler, Franz Jirsa, Raúl Carrey, Nicolas Valiente, Alfonso Muñoz-Martín, Wolfgang Wanek |
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| Přispěvatelé: | Junta de Comunidades de Castilla-La Mancha, Agencia Estatal de Investigación (España), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Generalitat de Catalunya |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Pollution
Groundwater hydrology Biogeochemical cycle Salinity Environmental Engineering 010504 meteorology & atmospheric sciences Nitrate attenuation media_common.quotation_subject Drainage basin Aquifer 010501 environmental sciences Structural basin Isòtops estables en ecologia 01 natural sciences Hidrologia d'aigües subterrànies Cicles biogeoquímics Environmental Chemistry Salinitat Groundwater Waste Management and Disposal Stable isotopes 0105 earth and related environmental sciences media_common Hydrology geography geography.geographical_feature_category Endorheic basin Variable density Sediment Biogeochemical cycles Land use Environmental science Stable isotopes in ecological research |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Dipòsit Digital de la UB Universidad de Barcelona |
| Popis: | Endorheic or closed drainage basins in arid and semi-arid regions are vulnerable to pollution. Nonetheless, in the freshwater-saltwater interface of endorheic saline lakes, oxidation-reduction (redox) reactions can attenuate pollutants such as nitrate (NO3−). This study traces the ways of nitrogen (N) removal in the Pétrola lake-aquifer system (central Spain), an endorheic basin contaminated with NO3− (up to 99.2 mg/L in groundwater). This basin was declared vulnerable to NO3− pollution in 1998 due to the high anthropogenic pressures (mainly agriculture and wastewaters). Hydrochemical, multi-isotopic (δ18ONO3, δ15NNO3, δ13CDIC, δ18OH2O, and δ2HH2O) and geophysical techniques (electrical resistivity tomography) were applied to identify the main redox processes at the freshwater-saltwater interface. The results showed that the geometry of this interface is influenced by land use, causing spatial variability of nitrogen biogeochemical processes over the basin. In the underlying aquifer, NO3− showed an average concentration of 38.5 mg/L (n = 73) and was mainly derived from agricultural inputs. Natural attenuation of NO3− was observed in dryland farming areas (up to 72%) and in irrigation areas (up to 66%). In the Pétrola Lake, mineralization and organic matter degradation in lake sediment play an important role in NO3− reduction. Our findings are a major step forward in understanding freshwater-saltwater interfaces as reactive zones for NO3− attenuation. We further emphasize the importance of including a land use perspective when studying water quality-environmental relationships in hydrogeological systems dominated by density-driven circulation. his work was financed by a PhD grant (BES-2012-052256) from the Spanish government, the PEIC-2014-004-P project from the Castilla–La Mancha regional government, the projects CICYT CGL2014-57215-C4-1-R, CGL2017-87216-C4-1-R and CGL2017-87216-C4-2-R from the Spanish Ministry of Economy and AEU/FEDER UE, and the project 2017SGR1733 from the Generalitat de Catalunya. |
| Databáze: | OpenAIRE |
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