Assess the annual effective dose and contribute to risk of lung cancer caused by internal radon 222 in 22 regions of Tehran, Iran using geographic information system

Seasonal Indoor Radon Assessment and Estimation of Cancer Risk: A Case Study of Obafemi Awolowo University Nigeria

Human exposure to indoor radon has been a subject of continuous concern due to its health implications, especially as it relates to lung cancer. Radon contaminates indoor air quality and poses a significant health threat if not abated/controlled. A seasonal indoor radon assessment of residential buildings of Obafemi Awolowo University was carried out to determine radon seasonal variability and to evaluate the cancer risk to the residents. AT-100 diffusion-based track detectors were deployed within living rooms and bedrooms for the radon measurement. During the rainy season, the average indoor radon concentration was 18.4 ± 10.1 Bq/m3, with higher concentrations observed in bedrooms compared to living rooms, whereas the average radon concentration was 19.0 ± 4.4 Bq/m3 in the dry season, with similar radon levels in living rooms and bedrooms. The potential alpha energy concentration values ranged from 1.62 to 7.57 mWL. The annual effective dose equivalent values were below the world average and recommended limits for public exposure. Of the three geological units underlying the residences, the buildings overlying the granite gneiss lithology have the highest radon concentrations with average value of 21.4 Bq/m3. The soil gas radon concentration to indoor radon concentration ratio over the granite gneiss lithology is 0.006. The estimated average lifetime cancer risk due to radon inhalation in the residences indicated a potential risk of cancer development in 178 persons in 100 000 population over a lifetime period. The average indoor radon concentrations were below the recommended limit, requiring no immediate remediation measures. Improved ventilation of residential apartments is recommended to minimize residents' risk to indoor radon.

Assessment of possible risks on human health by estimation of annual effective doses associated with radon in drinking water

Radon is the main source of radiation that people receive naturally. Twenty-four samples of drinking water were collected and analyzed from all communities of Yerevan city, Armenia, in order to assess Radon associated radiological risk on population health through the drinking water. The measurements were performed by Alfarad Plus - ARP radon meter. The obtained values were compared with the national and international recommended values and they were within the Maximum contaminant level recommended by the US Environmental Protection Agency, WHO and EU commission, also the national norms. As a consequence of direct consumption of drinking water annual effective doses due to the ingestion and inhalation of Radon were calculated. Annual committed effective dose received from drinking water consumption are within the recommended limit of WHO and EU Council (100 μSv y^-1) and UNSCEAR [United Nations Scientific Committee on the Effects of Atomic Radiation] (1000 μSv y^-1).