Radioactivity Traces

Press, Volume CVI, Issue 31117, 21 July 1966, Page 3

Radioactivity Traces

The National Radiation Laboratory’s air monitor at Nandi, Fiji, was the only one in the monitoring network which had so far given any indication of the passage of traces of radioactivity from the first French bomb test at Mururoa, said Mr G. E. Roth, director of the laboratory, yesterday. The concentration was very low indeed and was only just detectable. Mr Roth said the air monitor at Nandi (similar to those operated at Rarotonga, Auckland, Wellington and Christchurch), pumped more than 100 cubic metres of air through a glass fibre filter during a 24-hour period. Radioactive particles in the air were trapped in the filter, enabling the radioactivity in air near ground level to be readily detected. ‘The first traces of radioactive material in the air at Fiji were detected in the filter exposed at Nandi from 9 a.m. on July 15, to Saturday. July 16,” said Mr Roth. ‘‘Measurements on the following days showed that the indications were consistent with traces of radioactive debris from the French nuclear tests passing over the area. , “Although the radioactivity is extremely low and does not constitute any health hazard whatever, it provides i an indication that the radioactive debris from the nuclear test at Mururoa has taken about two weeks in its 1 westerly passage around the world before it reached Fiji. “In its passage around the world, the radioactive debris from the explosion has been

diluted so much by the huge masses of air with which it is mixed, that the concentration is very low indeed and only very little above the level of detection.”

Mr Roth said it appeared, from the delay since the [warning was given, that the French had waited for similar weather to explode their second bomb yesterday morning. Radioactive debris from that explosion was likely to follow the same course around the world and take about the same time as that from the first.