Assessment of the radiological impacts of treated phosphogypsum used as the main constituent of building materials in Jordan

Phosphogypsum (PG) was treated to reduce activity concentrations of 226Ra, which was found to exceed that permitted by international regulations. Treatment methods using hybrid water treatment, sulphuric acid treatment, mixed acid (H2SO4 and HNO3) treatment, household water treatment and calcium carbonate powder treatment were applied. Reduction of 226Ra content in phosphogypsum by 80–85 % can be achieved using these treatment processes. The radium equivalent activity (Raeq), gamma index (Iγ), alpha index (Iα), absorbed gamma dose rate (Din), and corresponding annual effective dose (Ein) were evaluated for public exposure due to the use of treated phosphogypsum in building materials and for other purposes. The calculated values of the (Raeq), (Iγ), and (Iα) for all the treated phosphogypsum samples are significantly below the recommended upper level of unity used as an index of radiological hazard. The measured mean value of the (Din) is about 20 % lower than the population-weighted average value of 84 nGy h−1 for the indoor absorbed dose rate. The estimated values of the indoor annual effective dose for all the treated phosphogypsum samples are significantly below the recommended upper level of 1 mSv. The mean value of the (Ein) is about 70 % lower than upper level of 1 mSv. In the overall assessment, it can be concluded that using treated PG in proportions up to 100 % of building materials and other applications will be safe from the radiation protection perspective.