Assessment of radiological hazards from radioactivity natural of cement used in Dwellings in Rio de Janeiro, Brazil

Abstract

Brazil is the fourth largest cement consumer in the world and the largest producer in Latin America, around 1.3% of global production. The main inputs in the manufacture of cement are limestone and clay. Few studies have been carried out in the country on the risk of these materials used in civil construction. Therefore, the objective of this present work is to evaluate the radiological danger that they can present to society. Gamma spectrometry analysis on 16 samples of different brands of cement used as construction material in Rio de Janeiro (Brazil) was performed in this study, using an HPGe detector and the Genie 2000 data acquisition software. Samples were set to count for an accumulation time of 14,400 s (4 h) and all measurements were corrected to eliminate background and backscattering. Activity concentrations are determined for 226Ra was from (41.2 ± 1.6 to 174.9 ± 3.9) Bq kg−1, 232Th was from (15.7 ± 0.5 to 43.1 ± 0.7) Bq kg−1 and 40K was from (82.6 ± 7.2 to 254 ± 17) Bq kg−1. To assess radiological health risks: mean values of Radium Activity Equivalent 150.0 ± 3.4 Bq kg−1, Annual Gonadal Dose Equivalent 468 ± 11 μSv year−1 and Lifetime Excess Cancer Risk (ELCR) 2.42 ± 0.06 were calculated. Total Absorbed Dose Rates ranged from 72.2 ± 1.7 to 225.1 ± 5.2 nGy h−1. The damage to collective health was also estimated from the annual effective dose rates with an estimated total cost of damage to health of US$ 130 million. Values are generally within global limits reported by UNSCEAR.