A dual isotope approach to identify denitrification in groundwater at a river-bank infiltration site.
Water Res
; 37(13): 3070-8, 2003 Jul.
Article
em En
| MEDLINE
| ID: mdl-14509693
ABSTRACT
The identification of denitrification in the Torgau sand and gravel aquifer, Germany, was carried out by a dual isotope method of measuring both the delta 15N and delta 18O in NO3-. Samples were prepared by an anion exchange resin method (Silva et al., J. Hydrol. 228 (2000) 22) with a modification to the AgNO3-drying process from a freeze-drying to an oven-drying method. The occurrence of denitrification in the aquifer was confirmed by comparing the reduction of dissolved oxygen, dissolved organic carbon and NO3- concentrations with the dual isotope signatures. High nitrate concentrations were associated with low delta 15N and delta 18O values, and vice versa. The denitrification accords with a Rayleigh equation with calculated enrichment factors of epsilon = -13.62@1000 for delta 15N and epsilon = -9.80@1000 for delta 18O. The slope of the straight-line relationship between the delta 15N and delta 18O data demonstrated that the enrichment of the heavy nitrogen isotope was higher by a factor of 1.3 compared with the heavy oxygen isotope. It is concluded that the identification of this factor is a useful means for confirming denitrification in future groundwater studies.
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Coleções:
01-internacional
Contexto em Saúde:
2_ODS3
Base de dados:
MEDLINE
Assunto principal:
Isótopos de Oxigênio
/
Abastecimento de Água
/
Monitoramento Ambiental
/
Nitrogênio
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Water Res
Ano de publicação:
2003
Tipo de documento:
Article