The radiological impact on some workers due to the natural radionuclides from some industries

A total of 37 different soil samples and 22 air samples were collected from natural industrial sources. The air samples were collected at a height of 1 m above the ground on 10.4 cm diameter filter paper (with a desired collection efficiency) using a high-volume air sampler. The activity concentration levels of naturally occurring radionuclides such as the U-238 series and Th-232 series were measured using high-resolution γ-ray spectrometry. Specific activities ranged from 3.9 to 8574 Bq/kg for different types of rocks for the U-238 series and from 2.9 to 6431 Bq/kg for the Th-232 series. The activity concentration for the air samples ranged from 0.29 to 0.56 Bq/m³ for the U-238 series and from 0.1 to 0.17 Bq/m³ for the Th-232 series at a 1 m circle. The γ-absorbed dose rates (nGy/h) due to contaminated ground and air submersion were calculated. The equivalent dose (mSv/y) for each organ was calculated. Then, the total annual effective dose (mSv/y) to workers due to the U-238 series and Th-232 series was estimated to be 0.6014 mSv/y.

Keywords: natural radioactivity, external exposure, effective dose, mining processes, milling processes, natural radionuclides, low radiation