###### Abstract  
This study evaluates the levels of natural radioactivity in surface soil samples across all districts of Mardin Province, Turkishye, using data from the Turkish Environmental Radioactivity Atlas. The activity concentration levels of Ra-226, Th-232, K-40, and Cs-137 were re-mapped, and radiological parameters (Ra\({}_{\text{eq1}}\), D\({}_{\text{R}}\), H\({}_{\text{ex}}\), AEDE, AEDE, and ELCR) were calculated for an environmental risk assessment. The average Ra-226 concentration (33.66 Bq-kg\({}^{-1}\)) exceeded the Turkiye average but remained near the UNSCEAR global median. The Th-232 concentration (29.37 Bq-kg\({}^{-1}\)) was lower than both reference values, while K-40 (385.63 Bq-kg\({}^{-1}\)) was below the Turkiye average but higher than the global median. The Cs-137 concentration (20.52 Bq-kg\({}^{-1}\)) surpassed the Turkiye average, with the highest value detected in Yesilli district of Mardin (75.05 Bq-kg\({}^{-1}\)), suggesting an anthropogenic influence. The radiological parameters indicated that the Ra\({}_{\text{eq1}}\) and H\({}_{\text{ex}}\) values remained within safe limits across all districts. However, the D\({}_{\text{R}}\) and AEDE exceeded UNSCEAR global medians in Omerli and Midyat, while the AGDE was elevated in six districts. The ELCR surpassed the global median only in Omerli. The districts of Artuklu, Derik, Kiziltepe, Mazidag, Midyat, and Omerli exhibited higher natural radioactivity, whereas Dargecit, Nusaybin, Savur, and Yesilli had lower risk levels. Nusaybin was identified as the least radiologically hazardous district. Given these findings, radiological parameters should be considered when selecting new residential areas. Further studies with an increased number of soil samples are recommended for a more precise environmental risk assessment. natural radioactivity; radiological risk assessment; surface soil; Mardin Province 2025  
15 4792  
E10  
Natural background radiation levels vary significantly across different geographical regions due to variations in soil and rock composition. While these levels are relatively stable, human activities, such as nuclear accidents, industrial processes, and medical applications involving radiation, can lead to elevated background radiation levels, making continuous monitoring essential for assessing potential radiological risks. The majority of background radiation exposure comes from natural sources, with terrestrial radiation being a major contributor. Terrestrial radiation arises from radionuclides in the uranium (U-238) and thorium (Th-232) decay series, as well as potassium-40 (K-40), which is widely distributed in the Earth's crust [4; 5; 6; 7]. Additionally, cosmic radiation contributes to background radiation levels, as high-energy particles from space interact with atmospheric atoms, producing secondary radiation that reaches the Earth's surface. Since terrestrial background radiation depends on the local geological structure, measuring soil radioactivity levels provides critical information about regional radiation hazards [8; 9; 10; 11]. The levels of natural radioactivity and their potential health impacts can vary due to factors, such as the geographical location and geological structure of the region [12]. Natural radioisotopes present in soil and water can enter the food chain, transferring from soil to plants and subsequently to human and animal metabolism. Determining the radiation dose to which living organisms are exposed from both natural and artificial sources, along with the potential damage it may cause, is of critical importance. Recently, background radioactivity levels have been increasing rapidly due to factors, such as nuclear accidents and medical procedures involving radiation. To assess the extent