Evaluation of the Relationship between Current Internal (137)Cs Exposure in Residents and Soil Contamination West of Chernobyl in Northern Ukraine

After the Chernobyl Nuclear Power Plant accident, the residents living around the Chernobyl were revealed to have been internally exposed to (137)Cs through the intake of contaminated local foods. To evaluate the current situation of internal (137)Cs exposure and the relationship between the (137)Cs soil contamination and internal exposure in residents, we investigated the (137)Cs body burden in residents who were living in 10 selected cities from the northern part of the Zhitomir region, Ukraine, and collected soil samples from three family farms and wild forests of each city to measured (137)Cs concentrations. The total number of study participants was 36,862, of which 68.9% of them were female. After 2010, the annual effective doses were less than 0.1 mSv in over 90% of the residents. The (137)Cs body burden was significantly higher in autumn than other seasons (p < 0.001) and in residents living in more contaminated areas (p < 0.001). We also found a significant correlation between the proportion of residents in each city with an estimated annual exposure dose exceeding 0.1 mSv and (137)Cs concentration of soil samples from family farms (r = 0.828, p = 0.003). In conclusion, more than 25 years after the Chernobyl accident, the internal exposure doses to residents living in contaminated areas of northern Ukraine is limited but still related to (137)Cs soil contamination. Furthermore, the consumption of local foods is considered to be the cause of internal exposure.