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Results of the Determination of He in Cenozoic Aquifers Using the GC Method
Author(s) -
Kotowski Tomasz,
Najman Joanna
Publication year - 2015
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/gwat.12311
Subject(s) - groundwater , aquifer , residence time (fluid dynamics) , flux (metallurgy) , environmental science , helium , tracer , hydrology (agriculture) , soil science , environmental chemistry , chemistry , geology , physics , nuclear physics , geotechnical engineering , organic chemistry
Applications of the Helium (He) method known so far consisted mainly of 4 He measurements using a special mass spectrometer. 4 He measurements for groundwater dating purposes can be replaced by total He ( 3 He + 4 He ) concentration measurements because the content of 3 He can be ignored. The concentrations of 3 He are very low and 3 He / 4 He ratios do not exceed 1.0·10 −5 in most cases. In this study, the total He concentrations in groundwater were determined using the gas chromatographic ( GC ) method as an alternative to methods based on spectrometry measurement. He concentrations in groundwater were used for the determination of residence time and groundwater circulation. Additionally, the radiocarbon method was used to determine the value of the external He flux ( J He ) in the study area. Obtained low He concentrations and their small variation within the ca. 65 km long section along which groundwater flows indicate that it is likely there is relatively short residence time and a strong hydraulic connection between the aquifers. The estimated residence time (ca. 3000 years) is heavily dependent on the great uncertainty of the He concentration resulting from the low concentrations of He, the external 4 He flux value adopted for calculation purposes and the 14 C ages used to estimate the external 4 He flux.