Development of methodology for identification and assessment of ecosystems with an underground source of tritium

The article considers the issues of working out the suitable approaches for identifying zones with the presence of underground near-surface waters with increased concentrations of tritium discharged into a surface reservoir. The following methods were used as possible methods: determination of tritium content in snow cover, determination of tritium content in vegetation in the form of tritium of free water and organically bound tritium, determination of tritium content in river water and coastal vegetation. The studies were carried out at a previously identified site where groundwater with a tritium concentration of up to 6000 Bq/l is present, located in the vicinity of the city of Obninsk (Kaluga region, Russia). As a result of the conducted research, it was concluded that the analysis of the distribution of tritium in vegetation is an excellent methodological technique for identifying areas of location of near-surface underground waters contaminated with tritium. As a control parameter, both the concentration of tritium in the free water of plants and the content of organically bound tritium can be used. To detect underground tritium contamination the most promising use is the following indicator - the content of OBT in the shoots of woody plants. This parameter is very informative, and the sampling procedure for its determination has no seasonal restrictions, unlike such parameters as the content of tritium in grass and leaves, the content of tritium in snow cover, surface waters, which are preferably collected only in summer or winter. It should be noted that the control of surface waters of the groundwater discharge zone may not be a sufficiently informative indicator for identifying areas of polluted water inflow, since it depends on the ratio of the volumes of leaking polluted groundwater and the annual flow of the watercourse.