Application of Tradescantia-based test systems for the assessment of genotoxic effects of environmental radioactivity of undisturbed mountain soils (Aragats Massif, Armenia).

Abstract

Plant test systems are a sensitive way to detect the genetic effects of various contaminants in environmental compartments: water, soil and sediments. Biotesting of the genotoxicity of soil samples with various activity concentrations of naturally occurring (²²⁶Ra, ²³²Th, ⁴⁰K) and artificial (¹³⁷Cs) radionuclides in soil, from the territory of the Aragats Massif (Armenia) was carried out with the application of the Tradescantia micronucleus (Trad-MСN) and stamen hair mutation (Trad-SHM) bioassays of Tradescantia (clone 02) model test-object in the soil - plant system. Undisturbed soil sampling was performed in the southern slopes of the Aragats Massif, from different altitudes (from 1000 to 3200 m above sea level). The soils of the Aragats Massif exhibited a background level of naturally occurring materials (NORM) activity. The highest variability was indicated for ⁴⁰K. The activity concentration of ¹³⁷Cs in soils exhibited a naturally increased as the altitude increased. Tradescantia (clone 02) was grown on the undisturbed soils in the greenhouse. To determine the level of genotoxicity of the studied soil samples, the Tradescantia-based Trad-MCN and Trad-SHM tests were applied. The activity concentrations of NORM and artificial ¹³⁷Cs in soil and phytomass were determined using an HPGe detector-based gamma spectrometer (Canberra). Tradescantia (clone 02) accumulated mainly ⁴⁰K, accumulation of ²²⁶Ra observed in one soil sample. In the areas with elevated activity of NORM, levels of genotoxicity were significantly higher compared to the control soil sample with the low rate of spontaneous mutation frequency. The positive correlation between genetic damages of Tradescantia (MCN and SSH) and contents of ⁴⁰K and ²²⁶Ra in soils was revealed. The obtained results indicated the possibility of using Trad-MCN and Trad-SHM tests of Tradescantia (clone 02) for biotesting of background radioactivity in natural areas.