ISSN:
1432-0495
Keywords:
Groundwater
;
Isotope
;
Tunnel
;
3H
;
δD
;
δ 18O
;
δ 13C
;
36Cl
;
NO3 −
;
HCO3 −
;
CO2
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract The change in groundwater chemistry along the groundwater flow path in the Matsumoto tunnel vicinity was studied, and the origin of the groundwater and dissoluted substances was determined. The relationship between the concentration of HCO3 −, Ca2+, and Na+, and CO2 gas pressure in the groundwater indicated that the HCO3 −, Ca2+, and Na+ were produced by the reaction of the CO2 gas in the groundwater and feldspar in the rocks. The relationship between the concentration of NO3 − and the Eh and pH values in the groundwater indicated that in an oxidative condition, ammonia-oxidizing and nitriteoxidizing bacteria used NH4 + and produced NO3 − and H+, and in a reductive condition, denitrifying bacteria used NO3 − and produced N2 gas and OH−. The stable hydrogen and oxygen isotopic ratio in the groundwater and precipitation indicated that the groundwater originated from precipitation that had fallen on the area. The concentration of3H and the stable hydrogen and oxygen isotopic ratios in the groundwater suggested that it has been getting warmer climatically for more than 60 years. The stable carbon isotopic ratio indicated that the HCO3 − in the groundwater, excluding deep well water, originated from CO2 gas produced by organic matter in the soil. The deep well water, which had a higher concentration of HCO3 − than the other groundwater sampled, was thought to have acquired HCO3 − though contact with rocks. The36Cl/Cl ratio indicated the recharge age of the deep well water sampled at a depth of 760 m at the foot of the plateau was recent.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00766886
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