§ Mr. Gwilym Jonesasked the Secretary of State for Wales (1) what evaluations he has made of the greatest causes of natural radiation to which the people of Wales are exposed; and if he will make a statement;
(2) what evaluations he has made of the greatest causes of man-made radiation to which the people of Wales are exposed; what proportion of this is emissions from medical X-ray equipment; and if he will make a statement.
§ Mr. Mark RobinsonThe National Radiological Protection Board has advised that almost 87 per cent. of the radiation to which people in Wales are exposed comes from natural sources. While there are local variations, the sources of natural radiation in order of decreasing contributions to the total average dose are radon and thoron in air, terrestrial gamma rays, internal radiation naturally in the human body and cosmic rays. Most of the radiation from man made sources comes from medical procedures and is due almost entirely to the use of X-ray equipment.