The modeling of changes in the specific activity of tritium in plants

Abstract

Birch juice is a drink made of birch sap of medium-sized wild trees at the springtime. It is popular especially in northern Europe and Asia on territories with occasionally waterlogged permeable soils. However, some of these areas coincide with highest tritium leakage ever recorded (Kyshtym, Chernobyl and Fukushima). Robust analyses on tritium levels (scintillation method) in the birch sap were carried out in location with a constant load of tritiated water between 2003 and 2016. Sampling the birch sap was carried out annually in season (usually from the final week of February to the first-week of April. Sampling of birch sap was usually has been carried out during the period when the daytime air temperature was within +(5–8) °C minimum for 3 days. During this period, began intensive sap flow. Data obtained is put in relation to air temperature and humidity in order to contribute to the understanding basic mechanisms of tritium intake via birch. Findings confirmed that tritium easily penetrates via water into any organism and it can accumulate there for much longer than its half-decay times. It was firstly revealed that it is possible to predict the concentration of this dangerous pollutant in the birch sap based on the temperature and humidity dynamics. And with continuous input of tritium into the environment, the concentration of tritium in free water increases polynomial. The specific tritium activity values due to the gradient of tritium concentration in the atmosphere-plant-ground system of the change in temperature and humidity. For the organization of monitoring and control, the possibility of radioecological safety for the affected areas was determined