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The results of a survey on the 22Na concentration in rain water samples collected at the Casaccia Nuclear Center is here reported. Monthly measurements for the period 1962–1968 were performed by a gamma-gamma sum coincidence spectrometer. Both the artificial and cosmogenic components were evaluated. An average value of 18 μCi/km2/yr was obtained as the best estimate of the natural component. The mean residence half time measured after the artificial component was 11.2 months.

134Cs has been measured in samples of rainwater collected monthly at the Casaccia Nuclear Center (Rome). Measurements were performed by a gamma-gamma sum coincidence technique on pooled yearly samples after a chemical separation of Cs. The results of these measurements are reported and compared with similar results obtained by other authors. The analysis of the data available led to the hypothesis that a major amount of this nuclide could have been injected into the stratosphere by nuclear tests before 1961. The contribution of the 1961 and 1962 explosions was less than expected, taking into account the increase of 137Cs. The first Chinese test during 1964 seems to have given a detectable contribution t0 134Cs concentration in rainwater. During the period 1961–1965 the average yearly deposition was 33 ± 7 μCi/km2, while after 1965 it decreased to an average value of 2.2 ± 1.0 μCi/km2. The average 134Cs/137Cs ratio was about 1 per mine during the period 1961–1969. On the basis of the data reported, the origin of 134Cs world-wide contamination is attributed to nuclear test explosions: whilst in some cases a good experimental evidence of soil or bomb material activation exists, the available data are not sufficient to assess a 134Cs production due to fission.

The values of 181W concentration in air and deposition in Rome (Italy) are reported for the period December 1968 January 1969. The origin of the 181W contamination is attributable to the Schooner event, a cratering test of the Plowshare project. The total deposition of 181W observed in Italy was 3765 ± 680 μCi/km2. The 185W deposition in Italy was evaluated on the basis both of the 181W/185W ratio in the main cloud of the Schooner event and of the 181W deposition in Italy. The dose equivalent delivered to the bone of 1 yr children as a consequence of the W isotope deposition was about 0.19 mrem.