Indoor Radon and Lung Cancer: National Radon Action Plans Are Urgently Required

Preliminary study of chromosome aberrations using Giemsa, two-colour fish, and micronucleus assays in lymphocytes of individuals living in elevated radon concentration areas

The frequencies of unstable and stable chromosome aberrations and micronuclei were examined in peripheral blood samples from 10 individuals living in elevated radon concentration areas (Takandeang Village, Mamuju, Indonesia). Blood samples from 10 people living in Topoyo Village were used as a control group. For unstable chromosome aberration analysis, a dicentric chromosome assay was conducted using conventional Giemsa staining. Chromosomal painting of chromosomes 1 and 4 using the fluorescence in situ hybridisation technique was also applied to four subjects to assess the stable chromosome aberration. Our study showed no significant increases across all groups in dicentric and other unstable chromosome aberrations, such as rings and acentric fragments. Translocations were found in one person from Takandeang Village and two Topoyo Village inhabitants. The translocations found in the subjects from Takandeang Village were due more to aging factors than to radon exposure. The number of micronuclei per 1000 binucleus cells in Takandeang Village inhabitants was not significantly different than that in the control group (p = 0.943). A more comprehensive analysis should be conducted in a subsequent study by increasing the number of study donors and the number of metaphases to be analysed in both dicentric chromosome assay and fluorescence in situ hybridisation assays. Such research could provide valid information on the cytogenetic effects of elevated indoor radon exposure.

Spatial modeling of geogenic indoor radon distribution in Chungcheongnam-do, South Korea using enhanced machine learning algorithms

Prolonged inhalation of indoor radon and its progenies lead to severe health problems for housing occupants; therefore, housing developments in radon-prone areas are of great concern to local municipalities. Areas with high potential for radon exposure must be identified to implement cost-effective radon mitigation plans successfully or to prevent the construction of unsafe buildings. In this study, an indoor radon potential map of Chungcheongnam-do, South Korea, was generated using a group method of data handling (GMDH) algorithm based on local soil properties, geogenic, geochemical, as well as topographic factors. To optimally tune the hyper-parameters of GMDH and enhance the prediction accuracy of modelling radon distribution, the GMDH model was integrated with two metaheuristic optimization algorithms, namely the bat (BA) and cuckoo optimization (COA) algorithms. The goodness-of-fit and predictive performance of the models was quantified using the area under the receiver operating characteristic (ROC) curve (AUC), mean squared error (MSE), root mean square error (RMSE), and standard deviation (StD). The results indicated that the GMDH-COA model outperformed the other models in the training (AUC = 0.852, MSE = 0.058, RMSE = 0.242, StD = 0.242) and testing (AUC = 0.844, MSE = 0.060, RMSE = 0.246, StD = 0.0242) phases. Additionally, using metaheuristic optimization algorithms improved the predictive ability of the GMDH. The GMDH-COA model showed that approximately 7 % of the total area of Chungcheongnam-do consists of very high radon-prone areas. The information gain ratio method was used to assess the predictive ability of considered factors. As expected, soil properties and local geology significantly affected the spatial distribution of radon potential levels. The radon potential map produced in this study represents the first stage of identifying areas where large proportions of residential buildings are expected to experience significant radon levels due to high concentrations of natural radioisotopes in rocks and derived soils beneath building foundations. The generated map assists local authorities to develop urban plans more wisely towards region with less radon concentrations.

Economic valuation of health benefits from using geologic data to communicate radon risk potential

BACKGROUND

Radon exposure is the second leading cause of lung cancer worldwide and represents a major health concern within and outside the United States. Mitigating exposure to radon is especially critical in places with high rates of tobacco smoking (e.g., Kentucky, USA), as radon-induced lung cancer is markedly greater among people exposed to tobacco smoke. Despite homes being a common source of radon exposure, convincing homeowners to test and mitigate for radon remains a challenge. A new communication strategy to increase radon testing among Kentucky homeowners utilizes fine-scale geologic map data to create detailed radon risk potential maps. We assessed the health benefits of this strategy via avoided lung cancer and associated premature mortality and quantified the economic value of these benefits to indicate the potential utility of using geologic map data in radon communication strategies.

METHODS

We estimated the change in radon testing among all 120 counties in Kentucky following a new communication strategy reliant on geologic maps. We approximated the resultant potential change in radon mitigation rates and subsequent expected lung cancer cases and mortality avoided among smokers and non-smokers exposed to 4 pCi/L of radon in the home. We then applied the value of a statistical life to derive the economic value of the expected avoided mortality.

RESULTS

The new communication strategy is estimated to help 75 Kentucky residents in 1 year avoid exposure to harmful radon levels via increased testing and mitigation rates. This equated to the potential avoidance of approximately one premature death due to lung cancer, with a net present value of $3.4 to $8.5 million (2016 USD).

CONCLUSIONS

Our analysis illustrates the potential economic value of health benefits associated with geologic map data used as part of a communication strategy conveying radon risk to the public. Geologic map data are freely available in varying resolutions throughout the United States, suggesting Kentucky's radon communication strategy using geologic maps can be employed in other states to educate the public about radon. As this is only a single application, in a single state, the economic and health benefits of geologic map data in educating the public about radon are likely to exceed our estimates.