PUBLIC HEALTH IN RADON­AFFECTED TERRITORIES

The aim of the study is to conduct the geoecological assessment of the territory’s radon hazard and its impact on the public health. Methods. The following methods were used during the study: cartographic method, geoinformation method, statistical method and mathematical modeling method. Secondary operations were carried out with the computer software Arc GIS 9.2, CorelDraw 9.0, Adobe Photoshop 10.0, Macromedia Flash MX, Statistica 10.0. Results. The article presents a methodological approach to studying the geographical distribution of radon. To ensure the quality of life for the population one requires a comprehensive radon monitoring, including the study of its natural background level as well as the area building structures and the rate of cancer related diseases. Analyzing the geotectonic typology of residential areas provides an opportunity to identify the main types of (human) settlements with a focus on their radon hazard level. While assessing the risk of cancer­related diseases and outlining the factors that affect the lung cancer rate it is essential to consider the deviations from the average ratio of nosological forms. One has developed the GIS mechanism to monitor territories, which ­ if combined with cartographic models ­ enables to quickly determine their radon hazard level. The suggested methodological approach makes it possible to identify the areas with ecological risk for the inhabitants due to the radon hazard of both populated land and the one to be populated in the future. The increasing emphasis is being laid on the residential areas located on tectonic fault lines. Conclusions. The natural background level of radon for the investigated region was identified during the integrated analysis of the territory radon hazard level. The cartographic approach reveals spatial patterns of cancer­related diseases and allows mapping the territory according to the degree of cancer risk.

Radon Impact at a Remediated Uranium Mine Site in Japan

This paper mainly illustrates the radon impact of the closed uranium mine site remediated in 2007. The site remediated is the waste rock site located on the steep slope of a hill about 1.5 km upstream from a residential area along a main ravine. Major remedial action was to cover these waste rock yards with weathering granite soil. The radon flux density after remediation was intended to be 0.1 Bqm−2s−1 in consideration with the natural background level around Ningyo-toge because there is no value of radon flux density regulated in Japan. Our action decreased the radon concentration in the site to natural background level, approximately from 10 to 40 Bqm−3, although relatively high concentration in excess of 100 Bqm−3 was observed before remediation. On the other hand, our action did not decrease the radon concentrations around the site in general. This fact proved that the limited source such as waste rocks affected the radon concentrations at neighboring area only. The similar tendencies were also observed in other environmental data such as radon progeny concentrations. In conclusion, these findings proved that our remedial action was successful against radon. This fact will lead to more reasonable action plans for other closed mine sites.