High radiation background areas

 

We are being continuously exposed to natural background radiation from sources such as Naturally Occurring Radioactive material (NORM) radionuclides present in the earth. This exposure is unavoidable. The radiation levels vary from place to place depending on the concentration of radionuclides present in our surrounding. Ramsar, Iran; Guarapari, Brazil; Yangjiang, China and coastal areas of Kerala are some examples of high radiation background areas.  The annual radiation doses received by the inhabitants in some locations exceed the annual doses recommended for occupational workers.

Ramsar, a city on the Caspian Sea in northern Iran, hosts the highest measured natural background radiation levels in the world. These high radiation levels in Ramsar are due to the deposition of Radium-226, one of the long- lived daughter products of Uranium-238 in local rocks. These rocks are also used in the construction of many local houses. The hot springs in the areas also contains higher levels of radioactivity. In India, the high background coastal areas are due to the monazite minerals which contain radioactive isotopes of thorium, and their decay products.  

In order to assess the public health from the exposure of inhabitants, extensive studies were carried out in such areas. The studies on the biological effects of prolonged exposure to higher levels of natural radiation in the inhabitants of Ramsar showed no harmful bio-effects.