Occurrence in rainwater, freshwater, and the atmosphere

Water samples taken during 1985 and 1986 from the Rhone river exhibited Tc radioactivities ranging from 0.1-2.1 mBq/1 [42]. Tc in rain and dry fallout were collected monthly in the summer of 199.3 at Nakaminato, Japan in containers of distilled water with a collection area of 0.21 m-. After concentration Tc was measured by ICP-MS. Values of 0.23 and 0.36 mBq m - of Tc were observed [43], 

There arc only a few reports concerning Tc concentrations in the atmosphere. Early measurements of Tc in the surface air of Seville, Spain, where no nuclear installations existed, were done. Filter samples taken from 1965 to 1967 were analyzed, llie average radioactivity of Tc per 1000 m- of air yielded 1.23 mBq in 1965, 0.71 mBq in 1966 and 0.78 mBq in 1967 144). In 1988 a compilation of Tc radioactivity data and Tc/ Cs activity ratios determined in rainwater and air was reported (Table 4.2.A). 

---