FLUCTUATIONS OF GROUNDWATER RADON AND CHEMICAL-SPECIES IN BASALTIC AQUIFERS

Surveys of radon and trace elements concentration in groundwaters have Seen carried out. Two different series of aquifers were monitored. On e is located along the Pacific coast of Mexico, characterised by an in tense seismic activity. The second one is located on the coast of the Gulf of Mexico, where, on the contrary, low seismic activity is observ ed. Radon determinations are performed with track detectors LR 115 typ e II and with automatic radon probes. Concentration levels of trace el ements in water samples were measured with an Inductively Coupled Plas ma Mass Spectrometer. Differences of the geochemical response of each aquifer depend on its specific geological context and recharge pattern .