Assessment of the hydrological behaviour of tritium in the Semipalatinsk Nuclear Test Site (Kazakhstan) using deuterium

Titre du congrès :International conference Ecoanalytics of Central Asia Ville du congrès :Almaty Date du congrès :10/10/2007

The interpretation of tritium migration in surface and/or underground waters at the former nuclear test site at Semipalatinsk (STS) can greatly benefit from the analysis of other chemical or isotopic tracers, such as deuterium and 18O. Such measurements can be used to characterise the water cycle in the region, and to identify the contribution of different water sources (meteoric, lake, ground or river waters) and hydrological processes (mixing, recharge or evaporation) to tritium migration. In this study, analyses of tritium in waters from an area of the STS close to the Maiysk region were supported by measurements of hydrogen (D/H) isotopic ratios in the same waters with a view to identifying possible tritium exchanges at the surface water/atmosphere interface. Particular attention was paid at establishing whether or not evaporation processes in salt lakes lead to a significant increase in the content of heavy hydrogen isotopes (deuterium and tritium) in the brines. In cases where evaporation processes were found to be significant, the evaporation rate of the remaining water was estimated with the aid of the deuterium measurements.