HC Deb 07 May 1959 vol 605 cc556-62
46. Mr. G. M. Thomson

asked the Prime Minister the latest levels of strontium 90 for the various regions of the United Kingdom, including Scotland.

52 and 53. Mr. Palmer

asked the Prime Minister (1) the measurements for the deposition of strontium 90 over the last twelve months in an area including the Tees Valley and the Cleveland Hills;

(2) the maximum and minimum measurements for the deposition of strontium 90 in the United Kingdom over the last twelve months; and where these measurements were obtained.

The Prime Minister

It would perhaps help the House if I were to explain the method by which these figures are reached. About half a dozen monitoring stations are established in different parts of the country (including one in Scotland) and at these the deposition of strontium 90 is measured in relation to the rainfall. It has been found that the amount of deposition of strontium 90 varies with the rainfall. It is therefore possible to estimate what amount of strontium 90 is likely to be deposited in any area in the United Kingdom for which the rainfall is known.

In addition, samples are taken of strontium 90 in food (especially milk), herbage and soil in many different areas and these supply complementary information. The figures are published from time to time and copies are available in the Library.

I might add that the Tees Valley and the Cleveland Hills are not in an area of very heavy rainfall.

The maximum deposition of strontium 90 observed has been at two stations on Snowdon, both of which are at a high altitude. The latest Atomic Energy Authority report on this subject gives the figures for these two stations for the first six months of 1958 (8.3 and 9.6 millicuries of strontium 90 per square kilometre). These levels were some four to five times the representative value for the country as a whole. This reflects the higher rainfall of that area.

Mr. Thomson

Will the Prime Minister, in answer to the second part of Question No. 46, give similar figures for Scotland to those which he has given for Wales?

The Prime Minister

I gave the figures only for these two very high stations on a mountain. With regard to Scotland as a whole, they are given in the general figures.

Mr. Palmer

Would the Minister not agree that it would be useful if rather wide publicity were given to these detailed figures which, he says, are available to us in a particular place?

The Prime Minister

They are available and they are published.

Mr. Mason

Is it not also true that the Prime Minister keeps giving the House figures which are at least twelve months old—as the right hon. Gentleman stated, for example, for mid-1958—and that the serious fall-out of radioactive strontium 90 has taken place in the last eight or nine months since the project "Argus "missile tests and the Russian "dirty "tests? Therefore, will not the Prime Minister try to inform the House with more up-to-date figures and point out that strontium 90 is having more effect than he is leading us to believe?

The Prime Minister

Of course, there has been this additional fall-out, but the figure must be left for the experts to work out. It takes about three months to complete a determination of strontium 90. Then there must be the interpretation of the results in relation to each other. To be of any value, the results should cover a sufficiently lung period to iron out temporary or short-term effects of unusual phenomena. I could not, therefore, ask those who are responsible for this to alter what they regard as the right scientific processes which should be followed.

Mr. Gaitskell

In the statement which the Prime Minister gave the House some little time ago, the impression was created in the minds of most of us that the extent of strontium 90 deposited in this country had doubled within a year. Do I understand from what the right hon. Gentleman has just said that that is not the case and that the doubling was over a shorter period, from May, 1958? Is it not possible to indicate the changes in strontium 90 per unit of rainfall per inch, or whatever other appropriate indicator is suitable?

The Prime Minister

With regard to the second part of the question, I will ask my advisers whether that is a practicable and sound scientific method. It might be helpful if I were to try to summarise what the Medical Research Council said about the hazards to man of radioactive strontium in fall-out. In paragraphs 281 to 284 of its Report. the Medical Research Council said that the maximum permissible level of strontium 90 in the human skeleton accepted by the International Commission on Radiological Protection corresponds to 1,000 strontium units, but that this is the maximum permissible level for adults in special occupations. It is not suitable for application to the population as a whole or to children.

The Medical Research Council concluded that the maximum allowable concentration of strontium in the bones of the population should not be the figure of 1,000, but for working purposes should be 100, and that in the light of knowledge at present available, immediate consideration would be required if the concentration showed signs of rising greatly beyond ten. It has not reached anything like that yet.

48. Captain Pilkington

asked the Prime Minister what measures have been taken to reduce nuclear radiation, other than that caused by bomb tests; and by how much it is expected that this type of radiation will be decreased.

The Prime Minister

It is not possible to reduce radiation from the principal source to which mankind is exposed, namely the natural background.

As regards the medical uses, Lord Adrian's Committee has just issued an interim report which needs careful study. I would also refer my hon. and gallant Friend by way of example to the Code of Practice for the Protection of Persons exposed to Ionising Radiations. As regards industrial radiation, various measures have been taken. It is the policy of the Government that all operations involving the use of ionising radiations shall be carried out in such a way as to keep to a minimum the extent to which persons are exposed to such radiations.

Captain Pilkington

Can my right hon. Friend say to what extent it is expected that these measures will be effective? If they amount to one unit, will they not annul the increase of radiation Which has been brought about by the nuclear tests?

The Prime Minister

That is a calculation which my hon. and gallant Friend has made. Obviously, we must do our best to reduce what it is within our power to reduce. What is within our power is this very large amount from medical uses, a considerable amount from industrial uses and this amount from the nuclear explosions. All these we must try to reduce. We should, however, keep them in proportion, although nobody is more anxious than I that the negotiations at Geneva should have the effect of taking out the last, although by no means the most important, of these three.

Sir G. Nicholson

Is it not probable that since the dawn of human history there have been wide variations in the amount of nuclear radiation to which the human frame has been exposed and that it varies in different parts of the world? Is it not fair to deduce, therefore, that the human frame is most adaptable? Would not public opinion be reassured if this was stressed to a rather greater degree?

The Prime Minister

We must try to keep these things in perspective. I have tried to give the facts as objectively as possible. At the same time, for a great number of reasons, of which the medical is by no means the greatest, I would like to see, if we can only get it, an agreement between the great Powers dealing first with inspection and control, a really effective agreement among the great Powers, not merely from the medical point of view, but, perhaps even more important, from the political point of view of an advance in our relations.

Mr. Bevan

Would it not be misleading to speak about the adaptability of the human organism over centuries of exposure to radiation? If the changes take place gradually enough, is it not scientifically established that adaptation is easy, but that if the changes take place too rapidly they become fatal?

The Prime Minister

Yes, Sir. When we take the proportions, however, they, too, must be kept in perspective. They are still about 100, 22 and 1¼ or 1½.

49. Captain Pilkington

asked the Prime Minister what are the extremes of variation in natural radiation; and how the extent of such variation compares with the additional radiation caused by nuclear tests.

The Prime Minister

Natural radiation varies greatly in different parts of the world and, curiously enough, according to the buildings in which people live. In certain parts of the world, quite apart from the effect of the buildings, the natural radiation amounts to ten times the normal world level. Apart from some comparatively small local variations, the normal world level applies throughout the United Kingdom. We do not have these great extremes that some countries have. As regards buildings, natural radiation is normally lowest in wooden houses; the body dose in brick or concrete houses is about 25 per cent. higher than outdoors and the dose is somewhat higher again in stone and especially in granite houses.

With regard to the second part of the Question, radiation from fall-out is now estimated to be somewhere between 1 per cent. and 2 per cent. of the normal natural background radiation to which man, so far as we know, has always been exposed.

Captain Pilkington

Is it then possible that the present level of fallout is less dangerous than if one were travelling about on the Continent or living in particular buildings?

The Prime Minister

Certain places have very high radiation. The risks are greater but people have lived there and no doubt the adaptability of the human race allows them to do so.

Mr. Woodburn

Is the Prime Minister aware that his statement would seem to account for the splendid qualities of people from Aberdeen and that this radiation might be not wholly without benefit?

The Prime Minister

When I saw only yesterday this very remarkable and interesting figure about granite, my mind turned to Aberdeen.

50. Captain Pilkington

asked the Prime Minister whether, in the light of the latest information available, it is still the case that the proportions of radiation deriving from nuclear tests, from other man-made radiation, and from natural causes, are approximately in the proportion of one unit, 23 units and 100 units, respectively.

The Prime Minister

The proportion of 1, 22 and 100 may have been somewhat affected by the most recent tests, but the change would not amount to more than making the figure of 1 unit something between 1 and 2.

Captain Pilkington

In view of the figures given by my right hon. Friend, would it not be much more logical for the nuclear campaigners to worry rather less about radiation from nuclear tests and more about natural and man-made radiation, particularly in view of the fact that these nuclear tests are held only to perfect a deterrent weapon which both sides of the House are agreed is the best hope for peace?

The Prime Minister

I do not think that they can do much good by worrying about natural radiation, but I think that the very large figure of man-made radiation, other than nuclear—twenty times that of nuclear—is a source which we should be continually working at.

Mr. Chetwynd

In spite of the refinements of the arguments put by the right hon. Gentleman and all these figures, is the Prime Minister aware that most people in the country are extremely anxious and worried about the present situation?

The Prime Minister

I have never been able to ascertain quite the view of the party opposite on these matters.