RT Journal Article
T1 A multi-isotopic approach to investigate the influence of land use on nitrate removal in a highly saline lake-aquifer system
A1 Valiente, Nicolás
A1 Carrey, R.
A1 Otero, Neus
A1 Soler, A.
A1 Sanz, D.
A1 Muñoz Martín, Alfonso
A1 Jirsa, F.
A1 Wanek, W.
A1 Gómez Alday, J.J.
AB 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 99.2mg/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 38.5mg/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.
PB Elsevier
SN 1879-1026
YR 2018
FD 2018-03
LK https://hdl.handle.net/20.500.14352/12009
UL https://hdl.handle.net/20.500.14352/12009
LA eng
NO Ministerio de Economía y Competitividad (MINECO)
NO Castilla la Mancha
NO Generalitat de Catalunya
DS Docta Complutense
RD 3 ago 2025