ASSESSMENT OF RADIATION DOSE FROM INHALATION OF OUTDOOR DUST CONTAINING NATURAL RADIONUCLIDES

Area of Science:

• Environmental Science
• Radiological Science
• Urban Ecology

Background:

• Urban surface sediments contain natural radionuclides like Uranium-238 (238U), Thorium-232 (232Th), and Potassium-40 (40K).
• Estimating radiation exposure from these radionuclides is crucial for assessing environmental health risks in populated areas.

Purpose of the Study:

• To quantify the concentrations of 238U, 232Th, and 40K in size-fractionated urban dust from Ekaterinburg, Russia.
• To estimate the effective dose received by adults from inhaling this dust under various activity levels.
• To compare the calculated effective doses with established safety guidelines.

Main Methods:

• Surface sediment samples were collected and fractionated by size (0.002-0.05 mm).
• Gamma-ray spectrometry was used to determine the activity concentrations of 238U, 232Th, and 40K.
• Effective doses were calculated based on typical urban dust concentrations and different physical activity scenarios (light, moderate, vigorous).

Main Results:

• Average concentrations in the dust fraction were 48 ± 7 Bq/kg for 238U, 28 ± 1 Bq/kg for 232Th, and 510 ± 20 Bq/kg for 40K.
• The total effective dose over 20 years for light activity was 5.6 μSv at a typical dust concentration (1 × 10-4 g/m3).
• For moderate and vigorous activities, doses were 9.9 μSv and 48.8 μSv, respectively, at the diurnal Maximum Permissible Limit (1.5 × 10-4 g/m3).

Conclusions:

• The effective doses from natural radionuclides in Ekaterinburg urban dust are relatively low.
• Inhalation exposure to these radionuclides, even at elevated levels, remains below the International Commission on Radiological Protection (ICRP) reference level.
• These findings suggest minimal radiological health risk from urban dust in Ekaterinburg.