Behaviour of Tritium and Tritiogenic Helium in Freshwater Lens Groundwater Systems: Insights from Langeoog Island, Germany

Table 2

Time since recharge for freshwater and seawater depending on groundwater ³H and ³He concentration (all numbers in TU) for simulation A7 with .

Freshwater	≥60 yr (^3He ≈ 5)	<10 yr	≥20 yr	<10 yr ()
Saltwater	≥40 yr (^3He ≈ 0.2)	Mixture of old seawater and	Mixture of seawater and ≥20 yr freshwater (brackish)	<10 yr ()