Isotope and Trace Gas Analyses as Tools to Assess Water Protection Zones in a Rural Area

Abstract

An example is presented for the application of groundwater age dating by tritium and chlorofluorocarbon (CFC) measurements to assess water protection zones. The investigation area is located in a rural area close to Osnabrück (Lower Saxony, Germany). Samples from 13 drinking water supply wells were collected in November 1995.

By using an exponential model, groundwater residence times were calculated for the wells. The tritium and CFC data showed comparable residence times with slightly higher values derived from the CFCs (especially F113). Most of the wells showed residence times around or below 10 years indicating a rather high vulnerability with respect to anthropogenic contaminations.