# Tritium Behavior from Vine to Wine
## 3 Results and Discussion
Connecting all the above parameters and observing the behavior of tissue-free water tritium (TFWT) from the vine during the growing season, Figure 4, one can conclude that the recorded values are in equilibrium with the environment and follow tritium concentration in precipitation. The absorption of H\({}_{2}\)O (thus HTO) vapor by the aerial parts of the plants (mainly the leaves) is a diffusion phenomenon through small pores (stomata) and is controlled mostly by climatic conditions (temperature, relative humidity, precipitation) and plant physiology. The level of TFWT can be considered a mixture of tritium level in atmospheric water vapor incorporated by diffusion and tritium level in precipitation diluted in soil and incorporated by the roots plant. Without identifying a predictable behavior, the tritium activity concentration of TFWT varied between 6.3 +/\(-\) 1.6 TU in November (2021) and around 19 TU in July-August, its level being influenced if the precipitation occurred before the time of sampling. Maximum tritium activity was recorded in August for the dry years and in June for the rainy years. The tritium level of OBT during the growing season of 2019, Figure 5, starts with around 10 TU in leaves, branches, and grapes in June, and it increases to around 15 TU in September for branches and grapes, and around 17 TU for leaves in October. The grapes used to obtain vine in October had a value of 13.3 +/\(-\) 1.8 TU, and the tritium activity concentration of ethanol of wine had a value of 11.7 +/\(-\) 1.7 TU, near the annual mean of precipitation, 10.9 +/\(-\) 1.5 TU. Figure 3: Tritium activity concentration in air and relative humidity during 2019–2023. The same behavior can be observed during the growing season of 2020, Figure 6, with values around 11 TU in the early stage of development, June, and maximum values around 20 TU in September for all observed components of the vine. The grapes of October had a value of 17.5 +/\(-\) 2 TU, and the tritium activity of wine ethanol had a value of 14.1 +/\(-\) 1.9 TU, slightly higher than the annual mean of precipitation, which was 10.6 +/\(-\) 1.5 TU. The last year with a precipitation deficit was 2021, during the growing season recording May-October, an amount in precipitation of 257 mm, one of the lowest precipitation amounts recorded for the 6-month growing period. The tritium level of OBT of vine components started in June below 10 TU, and it increased to a maximum of around 17 TU in October, with a value of ethanol wine of 14.8 +/\(-\) 1.9 TU, Figure 7.  
Figure 4: Tritium activity concentration in TFWT of the vine during the growing seasons compared with tritium in the environment during 2019–2023. Figure 5: Tritium activity evolution during the growing season of 2019 in vine leaves, vine branches, grapes, and wine. The year 2022 was the year with an 8% surplus of precipitation above the normal precipitation of this location during the growing season May-October, recording 446.6 mm, Figure 8, considerably higher than the amount of precipitation from the previous year. The OBT tritium level of vine parts started in June at around 10 TU, and it increased to a maximum of around 15 TU in September. The OBT tritium level in the grape of October was 12.8 +/ \(-\) 1.7 TU, and the OBT tritium level in wine ethanol was practically the same, taking into account measurement uncertainty, 11.5 +/ \(-\) 1.6 TU. The annual mean precipitation was 11.4 +/ \(-\) 1.6 TU. The last year of observations was 2023, another year with a surplus in precipitation of 16.8% above the normal amount of precipitation of this location. The amount of precipitation during the period May-October was 429.8 mm, lower than the previous year. The same behavior of OBT tritium level is recorded in Figure 9, around 9 TU in June for all vine parts, and a maximum in September, around 17 TU. Figure 6: Tritium activity evolution during the growing season of 2020 in vine leaves, vine branches, grapes, and wine.