Abstract
The concentrations of tritium, helium isotopes and neon have been measured in groundwater samples from a shallow and deep groundwater system recharged by bank infiltration from the Oder River in northeastern Berlin, Germany. The apparent 3H/3He ages show a distinct variation. They increased from only a few months to >40 years along the flow path. The farthest wells from the river have high concentration of 4He terrigenic which is around 5 × 10?5 (ccSTP/kg). The highest values for stable 3H (3H + 3Hetrit) were encountered at a 2.6 kmdistance from the river.
Highlights
Both tritium and helium isotopes have been used as environmental tracers of groundwater flow in a variety of hydrogeologic settings
The concentrations of tritium, helium isotopes and neon have been measured in groundwater samples from a shallow and deep groundwater system recharged by bank infiltration from the Oder River in northeastern Berlin, Germany
The zero values of 4He terrigenic concentrations appear in calculations as a negative values reflect that assumption of excess air formed by complete dissolution of small air bubbles trapped in the soil during infiltration, and composition of excess air is identical to air, is not significant in most cases and the He/Ne ratio of excess
Summary
Both tritium and helium isotopes have been used as environmental tracers of groundwater flow in a variety of hydrogeologic settings. The 3H/3He ratio has been used successfully in dating groundwater less than 50 years old [1,2,3,4], while 4He has been used to quantify groundwater flow rates at both long [5] and intermediate travel times [6]. [3Hetrit] is defined as the fraction of the total 3He produced by 3H decay It was calculated by the difference between the measured concentration [3Hemeas] and the concentrations of all other 3He components: [3Heeq]: equilibrium, [3Heexc]: excess air, and [3Heterr]: terrigenic. The equilibrium concentration in water [3Heeq] is determined by the water temperature and the ambient air pressure (altitude) during recharge Solubility data for He and Ne isotopes are taken from Weiss (1970) [12] and from Benson and Krause (1980) [13]. If the water sample contains 3Heterr, which may be present in aquifers where rocks are enriched in U or Th, or in groundwater samples in which young water has mixed with relatively old water containing terrigenic, and in some cases, mantle He, in these cases, the Ne concentration must be measured and can be used to calculate the additional 3Heterr [15]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
