§ Mr. Ioan L. Evansasked the Secretary of State for Education and Science what is the latest information he has received about the content of strontium 90 in the water supply and in agricultural products grown in this country.
§ Mr. CroslandConcentrations of strontium 90 in drinking water in 1963 were the subject of a report by the Minister of Housing and Local Government in August, 1964. Drinking water contributes a very small proportion of the total ingestion of radioactivity in diet.
Concentrations of strontium 90 in human diet (including agricultural products) during the whole of 1963 and in milk during the first six months of 1964, were the subject of a report by the Agricultural Research Council's Radiobiological Laboratory published in September, 1964; in February, 1965, the Laboratory produced a report on concentrations of strontium 90 in milk during the latter half of 1964. Experience shows that the ratio of strontium 90 to calcium in milk is closely indicative of the ratio in the average diet.
Reports on concentrations of strontium 90 in drinking water and human diet respectively during the whole of 1964, and in milk during the first half of 1965, will be published shortly.
Dietary contamination reached a peak in the second half of 1963 as a result of nuclear weapons tests up to the autumn of 1962. In the absence of further testing of nuclear weapons in the atmosphere, levels are expected to decline.