Monitoring groundwater nitrate attenuation in a regional system coupling hydrogeology with multi-isotopic methods: The case of Plana de Vic (Osona, Spain)
dc.contributor.author
dc.date.accessioned
2016-10-25T06:27:54Z
dc.date.available
2016-10-25T06:27:54Z
dc.date.issued
2009-09-01
dc.identifier.issn
0167-8809
dc.identifier.uri
dc.description.abstract
This paper describes an integrated application of classical hydrogeological methods and multi-isotopic methods (δ15N, δ 18ON O3, δ34S, δ 18OS O4, δ13C) to assess the fate of groundwater nitrate in the Osona area, declared vulnerable to nitrate pollution by the Catalan Government in 1998, where nitrate is derived from intensive pig farming activities. Previous studies, involving a small area, indicated the occurrence of denitrification processes and their relationship with pyrite oxidation [Vitòria, L., Soler, A., Canals, A., Otero, N., 2008. Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: example of Osona (NE Spain). Appl. Geochem. 23, 3597-3611]. For the present study, groundwater samples were collected at 60 production wells at three different periods between April 2005 and May 2006 to confirm that denitrification takes place in a larger area than that studied by Vitòria et al. [Vitòria, L., Soler, A., Canals, A., Otero, N., 2008. Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: example of Osona (NE Spain). Appl. Geochem. 23, 3597-3611]. The aim of the study was to characterize the denitrification processes that control natural attenuation and to study their spatial and temporal variations. Nitrate concentration ranged from 10 to 529 mg/l, with 82% of the wells above the drinking water threshold of 50 mg NO3/l. Nitrate isotopic composition ranged from +5.3‰ to +35.3‰ for δ15N and from +0.4‰ to +17.6‰ for δ 18ON O3, and the samples showed a positive correlation between δ15N and δ 18ON O3, with a εN/εO ratio of 1.8, consistent with denitrification processes. The link between denitrification and pyrite oxidation is demonstrated by coupling chemical data with nitrate and sulfate isotopes. Furthermore, a spatial distribution of samples with significant denitrification was observed, allowing us to determine two main hydrogeological zones where natural attenuation was most effective. In several of the studied points, denitrification processes related to pyrite oxidation predominated and an estimation of the isotopic enrichment factors was performed using the temporal variations of nitrate concentration and the isotopic composition of dissolved nitrate (δ 15NN O3 and δ 18ON O3). Finally, using estimated isotopic enrichment factors, an approximation of the degree of natural attenuation of nitrate was performed on those samples showing clear denitrification, and a median value of 30% of contaminant diminution was obtained
dc.description.sponsorship
This work has been financed by CICYT projects CGL2005-08019-C04-01 and 02, CGL-2008-06373-CO3-01 and 02/BTE from the Spanish Government, the local authorities (Consell Comarcal d’Osona), the Catalan Water Agency (Age` ncia Catalana de l’Aigua), the local private association of livestock raising (ASSAPORC), the project SGR2005-00933 from the Catalan Government, the I3P Programme funded by the EU, and the ‘‘Jose´ de Castillejo’’ program of the Spanish Government
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier Masson
dc.relation
MICYT/2005-2008/CGL2005-08019-C04-02
info:eu-repo/grantAgreement/MICINN//CGL2008-06373-C03-03/ES/POLUCION DE LAS AGUAS SUBTERRANEAS DE ORIGEN AGRICOLA E INDUSTRIAL: MIGRACION DE CONTAMINANTES, ATENUACION NATURAL E INDUCIDA, Y VULNERABILIDAD/
dc.relation.isformatof
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.agee.2009.05.007
dc.relation.ispartof
© Agriculture, Ecosystems and Environment, 2009, vol. 133, núm. 1-2, p. 103-113
dc.relation.ispartofseries
Articles publicats (D-CCAA)
dc.rights
Tots els drets reservats
dc.subject
dc.title
Monitoring groundwater nitrate attenuation in a regional system coupling hydrogeology with multi-isotopic methods: The case of Plana de Vic (Osona, Spain)
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/embargoedAccess
dc.embargo.terms
Cap
dc.date.embargoEndDate
info:eu-repo/date/embargoEnd/2026-01-01
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
011661
dc.contributor.funder
dc.relation.ProjectAcronym