Marine radioactivity assessment of Mururoa and Fangataufa atolls

The International Atomic Energy Agency (IAEA) carried out an international project 'The Study of the Radiological Situation at the Atolls of Mururoa a nd Fangataufa' with the aim of assessing the present and future radiologica l situation at the atolls and making recommendations for either monitoring or remedial actions if they are deemed necessary. The paper concentrates on marine radioactivity aspects and gives an estimation of present radionucli de concentrations in water, sediment and biota of the Mururoa and Fangatauf a lagoons and the surrounding ocean. The dominant radionuclide in both lago ons is Pu in sediments (the total inventory is approximately 30 TBq). A dec line in radionuclide concentrations has been observed in recent years in la goon water, with the exception of H-3 and Sr-90, for which a contribution f rom underground sources is to be expected. Radionuclide concentrations in b iota from the lagoons and the surrounding ocean are low and consistent with previous measurements. The observed radionuclide concentrations in both la goons imply that no radiological risk exists for hypothetical inhabitants o f Mururoa and Fangataufa Atolls. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.