Risk assessment and management model for gamma radiation in building materials

To assess radiation risks in building materials, this study presents an analysis framework that incorporates dose, exposure time, and usage frequency. This framework was used to develop a risk assessment and management model based on a management table and a time-dependent exposure model for material use in dwellings. Additionally, a cost-benefit analysis was employed to validate the risk assessment and management approach. First, the risk matrix classifies materials according to dose limits; then, usage time defines the maximum exposure duration during which a person could be exposed for up to 80% of their lifetime. The mean activity concentrations of 226 Ra, 232 Th, and 40 K in the samples ranged from 1.3 ± 0.4 Bq·kg -1 to 94.3 ± 2.5 Bq·kg -1 , 0.97 ± 0.02 Bq·kg -1 to 91.70 ± 0.90 Bq·kg -1 , and 2.1 ± 0.8 Bq·kg -1 to 1023 ± 44 Bq·kg -1 , respectively. The effective dose ranged from 0.011 ± 0.001 mSv·y -1 to 1.094 ± 0.020 mSv·y -1 , with a mean value of 0.342 mSv·y -1 , which is above the recommended exclusion value of 0.3 mSv·y -1 (EC RP112) and below the dose limit of 1.0 mSv·y -1 for most materials. However, regular monitoring of radioactivity levels in geological materials is recommended before their use in construction. The results indicate that sand, cement, crushed stone, bricks, and some porcelain tiles present the highest risk under the established conditions. A cost-benefit analysis indicated that glass sand can replace river sand commonly used in dwellings, reducing radiation exposure risk and providing environmental benefits by reusing materials and lessening the effects of river sand extraction. An appropriate agency should be established to consistently monitor radiation and prevent related health problems. The constructed model can offer new insights for radiation risk assessment in environmental analysis. These results are significant for the safety of materials in the Brazilian construction sector and may provide information to support radiological risk management.