ISOTOPE-HYDROGEOLOGICAL CASE-STUDY ON THE PENETRATION OF POLLUTION INTO THE DEEP TERTIARY AQUIFER IN THE AREA OF MUNICH, GERMANY

In selected subareas of the city of Munich concentrations of H-2, H-3, C-13, C-14, O-18 and in some cases He-3 and He-4 together with hydroc hemical data including concentrations of chlorinated hydrocarbons (CHC ) were measured from groundwaters of approximately 58 wells tapping th e shallow (Quaternary) and the deep (Tertiary) aquifer. The results ob tained show that under hydraulic stress young tritium-containing groun dwaters in general have penetrated down to depths of as much as approx imately 60 m. The groundwater model ages decrease from recent values i n the Quaternary aquifer to approximately 15 kyr at a depth of approxi mately 200 m in the Tertiary aquifer. CHC, Cl-, NO3- and SO42- were de tected in some places in comparable depths to tritium. The results sho w clearly that it is necessary to introduce measures for the protectio n of the deep groundwater against pollution: Consumption should be lim ited to < 10(7) m3 yr-1 and the deep groundwater should only be used f or purposes which require drinking water quality.