Analysis of   ²²⁶Ra content and ²²²Rn exhalation rates in soil samples from Wukro, Tigray, using SSNTDs

Radon gas, a decay product of radium, is a significant environmental health risk due to its radioactive properties. Understanding the radium content and radon exhalation rates in soil is crucial for evaluating potential radiological hazards and ensuring environmental safety.

Soil samples were collected from twelve different locations in Wukro, Tigray, representing various soil types. The sealed can technique, using LR-115 Type-II plastic track detectors, was employed to measure radium concentrations and radon exhalation rates over a four-month exposure period. Radon mass exhalation rates, surface exhalation rates, and radium concentrations were calculated, and the Alpha Index was also determined to assess radiological risk.

The radon mass exhalation rates ranged from 0.18 × 10 ^-7 Bq.kg ^-1.d ^-1 to 0.82 × 10 ^-7 Bq.kg ^-1.d ^-1, with a mean of 0.48 × 10 ^-7 Bq.kg ^-1.d ^-1. Surface exhalation rates varied from 0.38 × 10 ^-6Bq.m ^-2.d ^-1 to 1.72 × 10 ^-6 Bq.m ^-2.d ^-1, averaging 1.02 × 10 ^-6 Bq.m ^-2.d ^-1. Radium concentrations ranged from 0.33 to 1.47 Bq.kg ^-1, with an average of 0.87 Bq.kg ^-1. A significant positive correlation between radium content and radon exhalation rates was observed, indicating a direct relationship between these variables. Clay soils exhibited the highest radium concentrations, while sandy soils had the lowest. All measured values were below the safety limit of 370 Bq.kg ^-1 recommended by OECD and UNSCEAR, suggesting no significant radiological risk in the study area.

This study highlights the importance of monitoring natural radiation levels for environmental safety. The findings provide a baseline for future studies and emphasize the need for continuous assessment to detect any long-term changes in soil radioactivity.