Radioactivity monitoring in French Polynesia and Reunion Island - Year 2002

The 543 atmospheric nuclear tests released radionuclides that have deposited themselves throughout the world. The Environmental Study and Surveillance Laboratory, 'Laboratoire d'Etude et de Surveillance de l'Environnement' (LESE), takes part, for more than 35 years, in the evaluation of the dosimetric consequences of these atmospheric depositions, especially those originating with the 41 tests realized in the Territory of French Polynesia from 1966 to 1974. This laboratory is established in Tahiti. The ingestion component of this dosimetric evaluation requires to collect the most representative samples of the 'feed ration' of the Polynesians living in the 5 archipelagoes of this territory. These samples belong to the marine environment of full sea, the 'lagoon' environment and the terrestrial environment. Certain samples of the physical environment are also taken (air, water). The 312 samples are measured by GAMMA spectrometry high resolution in order to determine levels of the lowest possible radioactivity. On 48 selected samples the levels of activity of the ⁹⁰Sr and ²³⁸Pu and ^239+240Pu are also given. During the year 2002 results fall under the continuity of a regular reduction in the levels of radioactivity since the stop, in 1974, of the French atmospheric tests. This residual radioactivity relates to primarily the ¹³⁷Cs. In term of ingestion dosimetry this artificial and residual radioactivity is lower than 3 μSv.an-1. This ingestion contribution corresponds to less than 1 % of exposure due to natural radioactivity (approximately 1000 μSv)