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 The Observatory detected very minute amount of radioactive Caesium-137  from air sample collected at King's Park       


(10 April 2011)


Very minute amount of artificial radionuclide Caesium-137 was detected for the first time together with the artificial radionuclide Iodine-131 from air samples collected at King's Park from 8 to 9 April 2011 (noon to noon).  The concentrations of Caesium-137 in this sample was 0.000067 Bq/m3, only 1/37,000,000 of the level that requires protective actions* (see figure below).

Since the amount of radioactive Iodine-131 and Caesium-137 detected are both very small, there will not be any impact on public health and no precautionary measures are required.  The environmental gamma radiation level in Hong Kong remains normal.  The Observatory will continue to monitor closely the radioactivity in Hong Kong and regularly announce the measurement results. 

   Activity of Caesium-137 in King's Park Air Sample  

* The concentration level required for taking protective actions is called `` Derived Intervention Level " (DIL).  The DIL for inhalation of Caesium-137 from the air is 2,480 Bq/m3. (Reference: Report No. 1 of the Radiological Protection Advisory Group, HKSARG: Derived Intervention Levels)


Last revision date: <21 Dec 2012>