wAbstract
@This study reports the impact of hydrological conditions on salinisation
and nitrate concentrations of a coastal aquifer located at the
Mediterranean Sea, southern Spain. Eighty-two samples of ground-
and surface water taken during two extreme hydrological events
between 1994 and 1996 at 25 different wells were evaluated with
regard to hydrochemistry, focusing on nitrate concentrations and
salinisation, which constitute the main hazard of this aquifer.
Furthermore, hydrochemical data were analysed by principal component
analysis (PCA). Additionally, in 2007 13 ground- and surface water
samples taken at 12 different locations were analysed for stable
isotopes of D/18O, and one sample was analysed for
15N. Since 1993 until present saltwater intrusion was
observed only during dry hydrological conditions in 1994; it showed
an irregular salinisation pattern probably related to locally
elevated hydraulic conductivities. Nitrate concentrations increase
significantly during wet hydrologic conditions owing to uptake
of nitrate by rising groundwater. Stable isotopes of groundwater
reveal an Atlantic origin of the precipitation that recharges
the aquifer and a minor amount of groundwater recharge by the
water coming from the La VinuelainΜͺΙ`j reservoir,
which is used for irrigation over the aquifer. 15N
isotopes point to a considerable input of nitrates derived from
organic fertilisers.
Keywords: Coastal contamination; Environmental isotopes; Water
resourcesx
Introduction and hydrogeological setting
Methods
Results and discussion
@Hydrogeochemistry
@Principal component analysis (PCA)
@Salinisation
@Nitrates
@Stable isotopes
Conclusions
Acknowledgments
References