§ Mr. Foulkesasked the Secretary of State for Scotland what radioisotopes were detected in air, rainwater and surface deposition in Scotland over the period between noon on Friday 2 May and midnight Sunday 4 May; what peak levels, in rems, were detected; and what are their respective chemical and biological half-lives.
§ Mr. AncramDuring the period 2–4 May air, rain and deposited radioactivity over Scotland contained a range of
Nuclide Effective half-life (days) Maximum measured activity in air (becquerels per cubic metre) Maximum measured activity in rain (becquerels per litre) Maximum measured activity in surface deposition (bec-querels per square metre) Iodine 131 7.5 2.7 9,400 8,000 Caesium 134 96 1.2 1,650 *1,200 Caesium 137 109 2.2 2,560 2,500 * This caesium 134 result was obtained in a different sample from that which gave the iodine 131 and caesium 137 result.
§ Mr. Foulkesasked the Secretary of State for Scotland how many samples of milk in Scotland have been collected and analysed for the presence of caesium 137; and what are the maximum levels which have been detected.
§ Mr. AncramThree hundred and six samples of milk were analysed for both caesium 134 and caesium 137. The highest values obtained in the period up to 13 May were:
Cs 134 Bqllitre Cs 137 Bqllitre Cow's milk 175 351 Goat's milk 93 329 Ewe's milk 288 543
§ Mr. Foulkesasked the Secretary of State for Scotland whether any tests have been performed on children, or other critical sections of the population, in Scotland to establish the actual dose absorbed of iodine 131 by the thyroid gland; and what levels have been detected as a result of contamination from the Chernobyl disaster.
§ Mr. John MacKayThe National Radiological Protection Board has undertaken measurements on some
226Wradionuclides attributable to the fallout from the accident at the Chernobyl nuclear power station. The more significant in radiological terms were iodine 131, caesium 134 and caesium 137. The peak concentrations detected are shown in the table. The values are given in units of becquerel, this rather than the rem being the appropriate unit for measuring radioactivity. Also given in the table are the effective half lives of the radionuclides in man. The effective half life of a radionuclide takes into account its physical, chemical and biological characteristics.
primary schoolchildren in the Glasgow area. Preliminary analysis has shown that none of the children in the group will receive a committed dose to the thyroid of more than 3 mSv. This is small by comparison with the International Commission on Radiological Protection reference level of 50 mSv at which action would be considered.
§ Mr. Foulkesasked the Secretary of State for Scotland how many readings of radioactivity in the air over Scotland were taken and analysed on each of the days between 26 April and 8 May; and if he will list the sites involved and the levels of each radioisotopes detected.
§ Mr. AncramThe Scottish Development Department does not maintain a record of all daily measurements of airborne radioactivity throughout Scotland. As part of the arrangements made to monitor the effects of fallout from the Chernobyl reactor accident, measurements were made by the United Kingdom Atomic Energy Authority at Dounreay, Eskdalemuir and Lerwick. the South of Scotland Electricity Board at Hunterston and Chapelcross, the Ministry of Defence at Her Majesty's naval base 227W Rosyth, and by the National Radiological Protection Board at Glasgow and Peterhead. For the period 2 to 8 May, the results of 78 measurements of radioactivity in air were reported to the Scottish Development Department. These results, which showed that levels of airborne radioactivity were of no significance in radiological terms, will be placed in the Library.