Chronic exposure to ionizing radiation raises important issues regarding individual adaptation and radiosensitivity, particularly as new mutagenic factors increase hereditary disease rates. This study identifies risk groups sensitive to radiation. Field and laboratory techniques included sampling environmental objects and measuring radiation levels in human blood and surrounding areas. Gamma radiation levels around a radioactive waste landfill and neighboring settlements ranged from 0.06 to 0.014 mSv/h. The study examined individual radiation sensitivity and DNA repair mechanisms. Genetic analysis revealed multiple mutant genotypes and an increased risk of environmental diseases among those with genome instability. Further genotyping of the DNA repair gene XRCC1 (Arg399Gln) was conducted, showing the distribution of genotypes: 62% Arg/Arg, 35% Arg/Trp, and 3% Trp/Trp in the study group, compared to 90%, 10%, and 0% in the control group. For the XRCC3 gene, the experimental group showed 77% Thr/Thr, 21% Thr/Met, and 2% Met/Met, while the control group exhibited 67%, 33%, and 0%, respectively. These findings highlight the genetic susceptibility of the population exposed to radiation in the Mangistau region.