TOPICAL REPORT High levels of natural radiation Report of an international conference in Ramsar

36 I ublic awareness about exposure to natural sources of radiation has been growing in recent years at a rather accelerated pace. Exposure to high levels of radon indoors, for example, has drawn considerable attention, and a number of countries have already adopted regulatory measures to mitigate exposure to radon in existing houses and to establish radon limits for new buildings. Another area of interest has been the presence of radium and radon in natural springs that are considered health resorts. And, in some areas of the world, the fact that external radiation levels are naturally much higher than normal has drawn the attention of many national and international bodies. This growing awareness has prompted more widespread scientific investigations, mainly at national levels. Such investigations have comprised large-scale surveys, radiochemical studies of natural environmental radionuclides, transport and transfer of radionuclides from the environment to man, and epidemiological studies to investigate health risks from high levels of natural radiation. In view of these developments, an international conference on the subject was held in November 1990 to review the latest information and to examine potential health impacts. The meeting was organized by the Islamic Republic of Iran's Atomic Energy Commission and held in Ramsar, a city located in an area having quite high levels of natural radiation, at the foot of the Elburz mountains on the southern coast of the Caspian Sea. Organized in co-operation with the IAEA, World Health Organization (WHO), United Nations Environment Programme (UNEP), and International Nuclear Track Society (INTS), the conference attracted nearly 200 specialists from Iran and 30 other countries. They built upon the work of previous international conferences on this sub-