Abstract
<jats:p>This study presents the first documented evidence of radioactive contamination in Western Abkhazia linked to the Chernobyl Nuclear Power Plant accident. The data obtained show that the level of ¹³⁷Cs radioactive contamination in the study area ranged from 50 to 160 kBq/m² in 1986. This corresponds to contemporary values of 25 to 79 kBq/m² when considering the radionuclide’s half-life. These measurements are highly consistent with data recorded in the adjacent Sochi region, where contamination levels varied between 40 and 185 kBq/m² in 1986. The local spatial variability of ¹³⁷Cs fallout was studied at four reference sites, located in different parts of the Mussera upland. All investigated sites demonstrated moderate variability, with value ranges of 17–25%. This heterogeneous distribution pattern is attributed to a combination of factors, including local topography, atmospheric deposition characteristics, and anthropogenic influence. Measurements of ambient dose equivalent rates ranged from 0.01 to 0.05 μSv/h. While no direct correlation was found between dose rates and the age or genesis of the underlying bedrock, a clear relationship was established between dose rates and terrain morphology. Elevated dose rates were consistently recorded in erosional landforms within topographically dissected areas. Analysis of peat cores from the Pitsunda Peninsula lagoon provided conclusive evidence of the Chernobyl disaster’s impact on Western Abkhazia, with a measured ¹³⁷Cs inventory of 20.7 kBq/m² (equivalent to 49.5 kBq/m² when corrected to 1986 values). Application of the non-equilibrium ²¹⁰Pb dating method yielded a peat accumulation rate of 0.1 cm/year.</jats:p> <jats:p> The Chernobyl accident resulted in a significant release of <jats:sup>137</jats:sup> Cs, leading to widespread radioactive fallout. This document assesses the <jats:sup>137</jats:sup> Cs inventory and its impact on ambient dose rates in the affected regions. </jats:p>