§ 45. Mr. Sorensenasked the Prime Minister what recent reports he has received from the United States Government or from other sources indicating the extent to which radioactive fall-out from nuclear tests now exceeds the scientifically recognised safety level; and what is the newly assessed danger to human health in the light of recent revelations.
§ Mr. MaudlingI have been asked to reply.
I would refer the hon. Member to my right hon. Friend the Prime Minister's statement of 28th April on radioactive fall-out. The reports of American statements which I have seen in the Press do not appear to justify any revision of the views he then expressed as to the dangers to human health.
§ Mr. Frank Allaunasked the Prime Minister why no figures have been given for strontium 90 in children's bones, or in milk and other foods after March, 1958, covering the period of increased fall-out; and if he will complete his recent statement in these respects.
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§ The Prime MinisterI would refer the hon. Member to paragraph 9 of my statement of 28th April on radioactive fallout. This emphasises that the
…measurements of very low levels of strontium 90 involve lengthy and complex processes of analysis, using specialised techniques and facilities The results of the food survey for 1958 are now being prepared for publication."—[OFFICIAL REPORT, 28th April, 1959; Vol 455. c. 1102.]I would also refer to the answer I gave on 7th May to a supplementary question from the hon. Member for Barnsley (Mr. Mason).
§ Mr. Frank Allaunasked the Prime Minister if he is aware that only twenty-seven analyses have been undertaken of the strontium 90 level in 1 to 5-yearsold children, although the average level in children of 1 to 2 years and of children 2 to 3 years is higher than in other age groups; and if he will have this research extended without delay.
§ The Prime MinisterOver a hundred measurements of strontium 90 in the bones of children from 1 to 5 years old have been made in the United Kingdom, of which twenty-seven were undertaken in the first three months of 1958. Every effort is being made, wherever possible, to increase the number of such analyses.
§ Mr. Frank Allaunasked the Prime Minister since, with the old rate of fallout, the United Nations Scientific Committee's Report estimated that the dose of radioactivity to human bone from strontium 89 would be up to 20 per cent. of that from strontium 90 and since these short-lived fission products will be more abundant with the faster rate of deposit, if he will give the figures of strontium 89 in fall-out now; and what proportion of the total radiation dose in bone this isotope is expected to give.
§ The Prime MinisterThe ratio of the dose to bone from strontium 89 as compared with that from strontium 90 depends, among other things, upon the ratio of the content of strontium 89 to strontium 90 in the diet at the time of ingestion and not on the relative content in the fallout. The values for diet in the United Kingdom in 1958 will be published shortly. It is expected that the dose from strontium 89 will fall well within the range 1–20 per cent. quoted by the United 93W Nations Committee. There is at present no reason to believe that the position will change significantly. The ratios of strontium 89 to strontium 90 in fallout will be published from time to time as results become available.
§ Mr. Mossasked the Prime Minister whether he will state the proportions of radiation derived from various sources affecting the mean marrow dose, assuming that no more tests of nuclear devices take place; and to what extent his figures would be altered in countries depending upon a plant-type diet.
§ The Prime MinisterI am advised that the average mean marrow dose of radiation from strontium 90 in the United Kingdom is at present less than 2 per cent. of that due to the natural background. The mean marrow dose of radiation from medical uses of X-rays is under consideration by the Adrian Committee and figures are not yet available. Comparable figures are not available from countries depending on a plant-type diet.
§ Mr. Mossasked the Prime Minister whether he will give an estimate of the proportions of radiation derived from various sources referring to the genetically significant dose; whether he will take into consideration the view of the Medical Research Council that the genetically significant dose from medical diagnostic radiology may be as much as 100 per cent. of the natural background radiation in countries with extensive medical facilities; and whether he will state revised figures.
§ The Prime MinisterI am advised that the genetically significant dose of radiation received by human beings in this country expressed as a percentage of that from the natural background is estimated to be at least 22 from medical diagnostic radiology and between 1 and 2 from fallout. The figure of at least 22 per cent. was derived from a fairly small investigation undertaken for the Medical Research Council when they prepared their report on the Hazards to Man of Nuclear and Allied Radiations. The matter is being more fully investigated by the Adrian Committee whose final report is awaited.
§ Mr. Mossasked the Prime Minister if he will state in mc/km2 the latest figures for accumulation of radioactive strontium 94W in bone in the United Kingdom, showing the extremes of local variation as well as the average and treating young children as a separate category.
§ The Prime MinisterThe latest published figures for the accumulation of radio-strontium in bone in the United Kingdom are contained in a recent Report from the Atomic Energy Research Establishment entitled "Radioactive and Natural Strontium in Human Bones", a copy of which is available in the Library. It is expected that a further report on strontium 90 in human bone will be published during the summer.
§ Mr. Frank Allaunasked the Prime Minister if his attention has been drawn to the warning given last week in part of Denmark against drinking from the normal water supply which had become dangerously radioactive; if he is satisfied that adequate monitoring is now carried out of all British drinking water; and what increase in radioactivity has been detected.
§ The Prime MinisterMy attention has been drawn to newspaper reports on this subject. I am advised that the arrangements for monitoring drinking water in the United Kingdom are adequate. In answer to the last part of the Question, I would refer the hon. Member to a report published in February this year entitled "A Preliminary Survey of Radiostrontium and Radiocaesium in Drinking Water in the United Kingdom", a copy of which has been placed in the Library of the House. It shows that the intake of these substances from drinking water is very small.