Controlled environment estimations of HT uptake by vegetation

A controlled environment system was constructed to determine the rate of uptake of tritium from atmospheric tritiated molecular hydrogen (HT). The system provided control of air temperature, air humidity, light intensity, and the concentration of HT in the air. Exposure of representative crop species for a period of one hour indicates a very low rate of oxidation of HT by the leaves of the plants. Deposition velocities were calculated to average 2 x 10-6 cm/s. Rates of incorporation of tritium into the organic fraction of the plants was a factor of 30 less than the rate of oxidation. These results suggest that the uptake of HT by plants is not a major source of dose to man following accidental HT releases. (author)