Abstract
This study investigates a biomonitoring approach using gamma-irradiated Barbula indica moss bags to evaluate atmospheric elemental deposition at the Tan Rai bauxite mining complex in Lam Dong, Vietnam. Moss samples were pre-treated with a 14 Gy dose to modify the matrix before a three-month dry-season deployment across four industrial nodes (P1-P4). Elemental quantification was performed using Total Reflection X-ray Fluorescence (TXRF). The results demonstrate a systematic increase in elemental concentrations for the irradiated matrix, with values rising by 12.4% to 28.1% compared to non-irradiated controls. Specifically, the relative difference in sequestration for Thorium (25.9%) and Uranium (28.1%) reached a peak at the industrial hotspot (P3), suggesting that radiation-induced surface modification may enhance the affinity for these elements. Comparative analysis indicates that while geogenic markers (Fe, Al, Ti) align with reported data from global bauxite-impacted regions, the elevated Thorium levels (mean 1.31 mg/kg) signify a distinct geochemical signature in the study area. These findings suggest that 14 Gy irradiated moss can serve as a stable passive sampler, providing a potential framework for environmental forensic monitoring in mining regions.