Estimation of 222Rn in water using a liquid scintillation counter

Full text: Regarding the importance for health, the radioactive materials in drinking water can be divided in two categories: alpha and beta emitting. The ingestion of anyone of them causes an internal contamination, but the alpha emitters are more dangerous due to the energy of particles. For these reasons the Norms consider the two types of materials separately. The 222Rn is a noble gas produced by the radioactive decay of 226Ra, which is widely distributed in uranium-containing soils and rocks. The radon readily escapes from the soil or rock where it is generated and enters surrounding water or air. The interest for the determination of 222Rn in water was increasing starting from the knowledge of its potential damage and to the employment of the 226Ra as natural tracer. The evaluation of the 222Rn concentration in water together with its associate uncertainties is important for radiation protection. This paper discusses and assesses the major sources of uncertainty in measurement of 222Rn in water. The uncertainties associated to the method (Standard Test Method for Radon in Drinking Water. American Society for Testing and Material D5072 - 98) were evaluated using the methodology of Kragten. Also, results of measurements and dose evaluations in organs due to of 222Rn in waters used for the consumption of population in the capital of the country are presented. (author)