Radioactivity at low levels

Press, 17 August 1981, Page 10

Radioactivity at low levels

Since 1976 recorded levels in New Zealand of strontium 90 and caesium 137, the two most potentially hazardous radioactive ; elements,, have been the lowest since measurements were first taken in 1960. The findings have been released by the National Radiation Laboratory in the 1980 annual report on en- ' vironmental radioactivity in New. Zealand- and : - the South.; Pacific ’ ■ From 1976 to 1980 the average amount of strontium 90 measured at nine New Zealand stations did not exceed three megabecquerels per square kilometre. They were the lowest readings since monitoring started in 1960. The highest reading of 133 megabecquerels was recorded in 1964. There were atmospheric nuclear tests staged by Russia and the

United States in 1961-62. During French atmospheric tests in the South Pacific from 1966 to 1974 average readings in New Zealand ranged from 9 to 51 MBq per square kilometre a year. . The concentrations of strontium 90 and caesium 137 in New Zealand milk in the last four years were also the- ‘ lowest recorded, said the re- d port. ...Continuous monitoring had... been conducted at five Pacific Island stations' since.French underground nuclear tests started in 1975. But no fresh fission products had g been detected. The report said that levels recorded in recent years were very small and did not constitute a health hazard. The radiation dose resulting from the long-term average levels was small when compared with the radiation from the natural background.