Environmental Radiation Monitoring in Hong Kong
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Environmental Radiation Monitoring in Hong Kong Technical Report No. 12 Radioactivity Bulletin 1994 Royal Observatory HONG KONG Crown Copyright Reserved Environmental Radiation Monitoring in Hong Kong Technical Report No. 12 Radioactivity Bulletin 1994 This publication is prepared by the Royal Observatory, Hong Kong. Permission to reproduce any part of it should be obtained through the Royal Observatory, 134A Nathan Road, Kowloon, Hong Kong. This publication is prepared and disseminated in the interest of promoting the exchange of information. The Government of Hong Kong (including its officers and employees) makes no warranty or representation, expressed or implied, or assumes any legal liability or responsibility (including liability for negligence) for the information contained herein or for any loss, damage, or injury (including death) which may result, whether directly or indirectly, from the supply or use of such information. Published April 1995 Contents Contents .............................................................................................................. i List of Tables ....................................................................................................... ii List of Figures ...................................................................................................... iv Acknowledgement................................................................................................ v Chapter 1 Environmental Radiation Monitoring in Hong Kong ............................................... 1 Chapter 2 The Sampling Programme..................................................................................... 3 Chapter 3 Methods of Measurement..................................................................................... 6 Chapter 4 Reporting Rationale.............................................................................................. 10 Chapter 5 Summary of Measurement Results........................................................................ 12 Chapter 6 Intercomparisons.................................................................................................. 15 References........................................................................................................... 16 i List of Tables Table 1 Specific gamma radioactivity of airborne particulates samples collected at King's Park ...................................................................................................... 17 Table 2 Specific gamma radioactivity of airborne particulates samples collected at Sha Tau Kok and Yuen Ng Fan........................................................................ 18 Table 3 Specific gamma radioactivity of air sampled by iodine cartridges at King's Park ...................................................................................................... 19 Table 4 Specific gamma radioactivity of precipitation samples ............................................ 20 Table 5 Specific gamma radioactivity of water samples ...................................................... 21 Table 6 Specific gamma radioactivity of terrestrial food samples......................................... 23 Table 7 Specific gamma radioactivity of aquatic food and seaweed samples ....................... 25 Table 8 Specific gamma radioactivity of sediment and land soil samples.............................. 26 Table 9 Specific radioactivity of tritium in precipitation and airborne water vapour samples........................................................................................... 29 Table 10 Specific radioactivity of tritium in water samples .................................................... 31 Table 11 Specific radioactivity of tritium in terrestrial food samples....................................... 32 Table 12 Specific radioactivity of tritium in aquatic food and seaweed samples ..................... 34 Table 13 Specific radioactivity of strontium-90 in precipitation samples ................................ 35 Table 14 Specific radioactivity of strontium-90 in terrestrial food, aquatic food, seaweed and land soil samples.............................................................................. 36 Table 15 Specific radioactivity of plutonium-239 in precipitation samples.............................. 38 Table 16 Specific radioactivity of plutonium-239 in aquatic food, seaweed, sediment and land soil samples............................................................... 39 Table 17 Specific radioactivity of carbon-14 in airborne particulates, airborne carbon dioxide, terrestrial food and aquatic food samples...................................... 40 Table 18 Comparison of specific radioactivity of artificial radionuclides in samples collected in 1994 and those collected in the Background Radiation Monitoring Programme (1987 - 91)..................................................................... 42 Table 19 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in January 1994................................................................... 44 ii Table 20 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in February 1994 ................................................................ 46 Table 21 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in March 1994.................................................................... 48 Table 22 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in April 1994....................................................................... 50 Table 23 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in May 1994....................................................................... 52 Table 24 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in June 1994 ....................................................................... 54 Table 25 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in July 1994 ........................................................................ 56 Table 26 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in August 1994.................................................................... 58 Table 27 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in September 1994.............................................................. 60 Table 28 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in October 1994 ................................................................. 62 Table 29 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in November 1994.............................................................. 64 Table 30 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in December 1994 .............................................................. 66 Table 31 Monthly mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in 1994................................................................................ 68 Table 32 Mean gamma and gamma plus beta radiation levels measured by radioactivity sonde on 13 April 1994 .................................................................... 69 Table 33 Mean gamma radiation level measured by radioactivity sonde on 29 September 1994 ............................................................................................. 72 Table 34 Mean gamma and gamma plus beta radiation levels measured by radioactivity sonde on 19 December 1994............................................................ 74 Table 35 Summary of intercomparison results for cockle flesh sample IAEA-134................. 76 Table 36 Summary of intercomparison results for sediment sample IAEA-135...................... 77 Table 37 Summary of intercomparison results for sediment sample IAEA-300...................... 78 iii List of Figures Figure 1 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network from January to June 1994 .................................................. 79 Figure 2 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network from July to December 1994................................................ 81 Figure 3 Daily mean ambient gamma dose-rates recorded by the Radiation Monitoring Network from March 1993 to March 1995 ....................................... 83 Figure 4 Annual mean ambient gamma dose-rates recorded by the Radiation Monitoring Network in 1994................................................................................ 85 Figure 5 Annual mean ambient gamma dose-rates recorded by the TLD Network in 1994 ................................................................................................................ 86 Figure 6 Vertical profiles of gamma and gamma plus beta radiation measured by radioactivity sonde on 13 April 1994........................................................................................ 87 Figure 7 Vertical profile of gamma radiation measured by radioactivity sonde on 29 September 1994......................................................................................... 88 Figure 8 Vertical profiles of gamma and gamma plus beta radiation measured by radioactivity sonde on 19 December 1994 ............................................................................... 89 Figure 9 Environmental