§ Mr. Skeetasked the Minister of State for Defence at what distance from the point of a nuclear explosion above ground the radionuclides strontium 90 and caesium 137 will affect human bone and muscle tissue, respectively.
§ Mrs. FennerI have been asked to reply.
The contamination of food especially milk by Sr-90 and milk and meat by Cs-137 following a nuclear explosion in the atmosphere will be affected by many factors, including the physical parameters of the explosion, meteorological condi- 172W tions and the characteristics of the agricultural environment. Levels of Sr-90 and Cs-137 already present in human bone and muscle tissue will be increased to some extent when food affected by fall-out is consumed. Previous experience of nuclear tests indicates that the increased levels in milk and meat can be detected at large distances from the point of detonation. The Medical Research Council reviewed in 1964 and 1966 the risks associated with Sr-90 and Cs-137 in human bone and muscle tissue in the United Kingdom following periods of large-scale nuclear weapon testing in the atmosphere. It is unlikely that the risks following the detonation of a single nuclear weapon in the atmosphere would approach those assessed by the Medical Research Council in the above studies.