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Titre :
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Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests
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Auteurs :
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R. Smith ;
S. Garabedian ;
M. Brooks
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Type de document :
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article/chapitre/communication
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Année de publication :
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1996
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Format :
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p. 3448-3456
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Langues:
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= Anglais
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Catégories :
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EAU
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Mots-clés:
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DENITRIFICATION
;
EAU SOUTERRAINE
;
MESURE
;
TRANSPORT DE CONTAMINANT
;
TRACEUR
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Résumé :
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The transport of many solutes in groundwater is dependent upon the relative rates of physical flow and microbial metabolism. Quantifying rates of microbial processes under subsurface conditions is difficult and is most commonly approximated using laboratory studies with aquifer materials. In this study, we measured in situ rates of denitrification in a nitrate-contaminated aquifer using small-scale, natural-gradient tracer tests and compared the results with rates obtained from laboratory incubations with aquifer core material. Activity was measured using the acetylene block technique. For the tracer tests, co-injection of acetylene and bromide into the aquifer produced a 30 mu M increase in nitrous oxide after 10 m of transport (23-30 days). An advection-dispersion transport model was modified to include an acetylene-dependent nitrous oxide production term and used to simulate the tracer breakthrough curves. The model required a 4-day lag period and a relatively low sensitivity to acetylene to match the narrow nitrous oxide breakthrough curves.
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Source :
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Environmental science & technology, vol.30, n°12
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