Izloženost stanovništva radonu i procena zdravstvenog rizika

Abstract

<p>ajor national and international scientific organizations have concluded that radon is a human carcinogen and serious public health problem. Radon was detected to be present in indoor air as early as the 1950s, but the potential health implications received little attention until the late 1970s. It is a naturally-occurring, odorless, colorless radioactive gas, which is given off by traces of uranium in soil and rock. It is found at varying levels all over the world. In outside air, radon is present in low concentrations. But in enclosed spaces (such as homes) it can sometimes build up to levels where corrective action should be taken. Radon can also be a problem in other types of buildings like small office buildings, schools and nurseries. Most people spend as much as 70-80 of the 24 hour day in the indoor environment, which constitute their major source of exposure. The series of cohort mortality studies of underground miners in countries throughout the world is highly informative with respect to the risk of lung cancer associated with exposure to radon. Epidemiological studies have been conducted to assess the general population&#39;s risk of lung cancer associated with indoor radon and complementary animal and laboratory studies have been carried out to address uncertainties in assessment of the risks associated with indoor radon. As a result, a rich body of evidences on radon and lung cancer that addresses all facets of the problem within of the framework of exposure, dose, and response has been gained. During the period 1998/2000 indoor radon activity concentrations were measured in 100 schools, nursery schools and homes in Novi Sad. During the sampling by active charchoal, the room to be surveyed was closed for 48h. By measuring gamma activity of radon daughters, radon activity concentration was determined. Using these results an average radon concentration for the total population in Novi Sad has been estimated. The distribution of activity concentrations is roughly lognormal. An arithmetic mean of 47.71 Bqm(na minus 3), and a geometric mean 23.66 Bqm (na minus 3) were obtained. In 96&nbsp;of samples indoor radon activity concentrations were below 200 Bqm (which is proposed SRJ action level). In most cases indor radon activity concentration can be significantly reduced by appropriate ventilation rate. By using proposed values for the expected radiation dose to target tissues in the lung and for resulting effective dose-equivalent from indoor radon concentration health risk has been evaluated. Lifetime relative risk (LRR) is the relative increment in lung cancer risk resulting from exposure to an agent such as radon. LRR increases with exposure. According to exposure age duration model and exposure age concentration model, smoking status, and average radon concentration in Novi Sad, the calculated LRR ranges from 1.103 to 1.247 for men and 1.113 to 1.261 for women population. To characterize risks to the population one can use the population attributable risk (AR) which indicates how much of the lung cancer burden could be prevented if all exposures to radon were reduced to the background levels of radon in outdoor air. According to exposure age duration model (EAD) and exposure age concentration model (EAC) and assumed lognormal distribution the calculated AR ranges from about 10.3&nbsp;to 14.6&nbsp;for men and 11.2&nbsp;to 15.9&nbsp;for women population. According EAC and EAD risk models, the number of lung-cancer cases due to residential radon exposure in Novi Sad population was projected to be 16 to 23 per year. This research is part of the project which aim is studying of 222 Rn-activity concentration of indoor facilities in Novi Sad and corresponding health risk assessment. This project is partly financed by City Department of Environmental Protection of Novi Sad.</p>