Gamma exposure dose in population surrounding radioactive waste deposit- Cesium-137 accident in Goiania

The radiological accident with Cesium-137 occurred in Goiania, Brazil, in 1987, and generated around 6000 tons of tailings due to the decontamination of the affected areas. These are located in a deposit located in an environmental conservation unit in the municipality of Abadia de Goiás, Goiás - Brazil. The objective of this study was to estimate the dose of environmental exposure in the population of Abadia de Goiás. The dose was estimated from the absorbed dose rate in air measured throughout the urban area in the municipality and area of the tailings deposit. For dose rate measurements, a high-sensitivity sodium iodide detector, coupled with a georeferencing system installed on a vehicle, was used. The device was positioned one meter from the ground and configured to perform measurements every 10 seconds. The mean dose rate absorbed in the air in the reservoir was 0.048 ± 0.004 μ Sv/h, while in the municipality area was 0.054 ± 0.006 μ Sv/h. From these values, the estimate of the dose of gamma exposure in the vicinity of the reservoir was 0.084 mSv/y, while in the urban area was 0.092 mSv/y. CONCLUSION: The environmental exposure dose values that the Abadia de Goiás population is subjected to is below the world average of 0.46 mSv/y for external exposure of terrestrial radiation sources