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| Titel |
Tracing atmospheric nitrate in groundwater using triple oxygen isotopes: evaluation based on bottled drinking water |
| VerfasserIn |
F. Nakagawa, A. Suzuki, S. Daita, T. Ohyama, D. D. Komatsu, U. Tsunogai |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-03), S.3547-3558 |
| Datensatznummer |
250018269
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| Publikation (Nr.) |
 copernicus.org/bg-10-3547-2013.pdf |
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| Zusammenfassung |
| The stable isotopic compositions of nitrate dissolved in 49 brands of
bottled drinking water collected worldwide were measured, to trace the fate
of atmospheric nitrate (NO3− atm) that had been deposited into
subaerial ecosystems, using the 17O anomalies (Δ17O) of
nitrate as tracers. The use of bottled water enables collection of
groundwater recharged at natural, background watersheds. The nitrate in
groundwater had small Δ17O values ranging from
−0.2‰ to +4.5‰ n = 49). The
average Δ17O value and average mixing ratio of atmospheric
nitrate to total nitrate in the groundwater samples were estimated to be
0.8‰ and 3.1%, respectively. These findings indicated
that the majority of atmospheric nitrate had undergone biological processing
before being exported from the surface ecosystem to the groundwater.
Moreover, the concentrations of atmospheric nitrate were estimated to range
from less than 0.1 μmol L−1 to 8.5 μmol L−1 with higher
NO3−atm concentrations being obtained for those recharged in
rocky, arid or elevated areas with little vegetation and lower
NO3−atm concentrations being obtained for those recharged in
forested areas with high levels of vegetation. Additionally, many of the
NO3−atm-depleted samples were characterized by elevated
δ15N values of more than +10‰. Uptake by
plants and/or microbes in forested soils subsequent to deposition and the
progress of denitrification within groundwater likely plays a significant
role in the removal of NO3−atm. |
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