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| Titel |
Age dating and flow path evaluation of groundwater by SF6 and microbe in the foot of Mt. Fuji, central Japan |
| VerfasserIn |
Chisato Yamamoto, Maki Tsujimura, Kenji Kato, Kazuyo Nagaosa, Koichi Sakakibara, Yohei Umei, Kazuma Ohara |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250130911
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| Publikation (Nr.) |
 EGU/EGU2016-11241.pdf |
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| Zusammenfassung |
| A variety of industries are developed at the foot of volcanic mountains in Japan and the
groundwater is major source for industrial activity in those regions. The age of groundwater
has been estimated to be from 10 to 30 years in Mt. Fuji regions by using 36Cl and 3H.
However, the age has not been evaluated using SF6 with higher time resolution in these
regions. Also, the total number of prokaryotes shows a specific value in each spring water,
suggesting different path and age of the groundwater. Therefore, we aim to estimate
residence time and the groundwater flow in three dimensions using the multi-tracers
approach; CFCs, SF6, the total number of prokaryotes, the stable isotopes of oxygen-18,
deuterium. We collected totally 25 spring water samples in Mt. Fuji and analyzed
concentration of inorganic ions, the stable isotopes of oxygen-18, deuterium, CFCs,
SF6.
The apparent age of the spring water was estimated to be ranging from 4 to 19 years at the
foot of Mt. Fuji. These results are reasonable as considering the existed age data by36Cl
(Tosaki, 2008) in this region. The spring water with younger age tends to show higher total
number of prokaryotes, suggesting that the groundwater flows dominantly through the
shallow and young lava with the higher total number of prokaryotes, leads to younger age.
Focusing on a specific spring water, the seasonal change of SF6 and total number of
prokaryotes were monitored. The spring water showed a younger age and higher total number
of prokaryotes during the high water flow season, whereas it showed an older age and lower
total number of prokaryotes. Therefore, the total number of prokaryotes shows a good
negative correlation with the residence time of the spring/ groundwater in space and
time.
This shows a possibility that the total number of prokaryotes could be a useful tracer of
groundwater for time and space in the three dimensions information. |
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