title: Nitrate pollution of groundwater; all right…, but nothing else?
abstract: Contamination from agricultural sources and, in particular, nitrate pollution, is one of the main concerns in groundwater management. However, this type of pollution entails the entrance of other substances into the aquifer, as well as it may promote other processes. In this study, we deal with hydrochemical and isotopic analysis of groundwater samples from four distinct zones in Catalonia (NE Spain), which include 5 different aquifer types, to investigate the influence of fertilization on the overall hydrochemical composition of groundwater. Results indicate that intense fertilizer application, causing high nitrate pollution in aquifers, also homogenize the contents of the major dissolved ions (i.e.; Cl(-), SO4(2-), Ca(2+), Na(+), K(+), and Mg(2+)). Thus, when groundwater in igneous and sedimentary aquifers is compared, significant differences are observed under natural conditions for Cl(-), Na(+) and Ca(2+) (with p-values ranging from <0.001 to 0.038), and when high nitrate concentrations occur, these differences are reduced (most p-values ranged between 0.054 and 0.978). Moreover, positive linear relationships between nitrate and some ions are found indicating the magnitude of the fertilization impact on groundwater hydrochemistry (with R(2) values of 0.490, 0.609 and 0.470, for SO4(2-), Ca(2+) and Cl(-), respectively). Nevertheless, the increasing concentration of specific ions is not only attributed to agricultural pollution, but to their enhancing effect upon the biogeochemical processes that control water-rock interactions. Such results raise awareness that these processes should be evaluated in advance in order to assess an adequate groundwater resources management.
authors.affiliation: Grup de Geologia Aplicada i Ambiental (GAiA), Centre de Recerca en Geologia i Cartografia Ambiental (Geocamb), Deptartament de Ciències Ambientals, Facultat de Ciències, Universitat de Girona, 17071 Girona, Spain. Electronic address: anna.mencio@udg.edu.
authors.forename: Anna
authors.initials: A
authors.lastname: Menció
authors.affiliation: Grup de Geologia Aplicada i Ambiental (GAiA), Centre de Recerca en Geologia i Cartografia Ambiental (Geocamb), Deptartament de Ciències Ambientals, Facultat de Ciències, Universitat de Girona, 17071 Girona, Spain; Institut Català de Recerca de l'Aigua (ICRA), Spain. Electronic address: jmas@icra.cat.
authors.forename: Josep
authors.initials: J
authors.lastname: Mas-Pla
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès, s/n - 08028 Barcelona, Spain. Electronic address: notero@ub.edu.
authors.forename: Neus
authors.initials: N
authors.lastname: Otero
authors.affiliation: Grup de Geologia Aplicada i Ambiental (GAiA), Centre de Recerca en Geologia i Cartografia Ambiental (Geocamb), Deptartament de Ciències Ambientals, Facultat de Ciències, Universitat de Girona, 17071 Girona, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Regàs
authors.affiliation: Institut Català de Recerca de l'Aigua (ICRA), Spain.
authors.forename: Mercè
authors.initials: M
authors.lastname: Boy-Roura
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès, s/n - 08028 Barcelona, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Puig
authors.affiliation: Àrea de Geodinàmica Externa i Hidrogeologia, Deptartament de Geologia, Universitat Autònoma de Barcelona, Bellaterra, Spain. Electronic address: joan.bach@uab.cat.
authors.forename: Joan
authors.initials: J
authors.lastname: Bach
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès, s/n - 08028 Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Domènech
authors.affiliation: Grup de Geologia Aplicada i Ambiental (GAiA), Centre de Recerca en Geologia i Cartografia Ambiental (Geocamb), Deptartament de Ciències Ambientals, Facultat de Ciències, Universitat de Girona, 17071 Girona, Spain.
authors.forename: Manel
authors.initials: M
authors.lastname: Zamorano
authors.affiliation: Grup de Geologia Aplicada i Ambiental (GAiA), Centre de Recerca en Geologia i Cartografia Ambiental (Geocamb), Deptartament de Ciències Ambientals, Facultat de Ciències, Universitat de Girona, 17071 Girona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Brusi
authors.affiliation: Grup d'Hidrologia Subterrània, Dept. D'Enginyeria del Terreny, Cartogràfica i Geofísica, Universitat Politècnica de Catalunya-Barcelona Tech, Spain. Electronic address: folch.hydro@gmail.com.
authors.forename: Albert
authors.initials: A
authors.lastname: Folch
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry*; D009566:Nitrates / Q000032:analysis*; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000706:statistics & numerical data
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical
keywords: groundwater; hydrochemistry; multivariate analysis; nitrate isotopes; nitrate pollution; water-rock interaction