Dosimetric Characteristics of the Cohort of the Siberian Chemical Plant Personnel in the Period 1950-2010

Purpose: To give a dosimetric characterization of the personnel of the Siberian Chemical Plant (SCP) subjected to prolonged technogenic occupational exposure to ionizing radiation (IR) in the period 1950–2010, as well as the cohort of the personnel of the SCP involved in working with uranium compounds.

Material and methods: SCP is one of the largest and oldest complexes of nuclear industry enterprises in the world, having experience in continuous dosimetric monitoring of personnel for more than 60 years. The database of the regional medical-dosimetric register of employees of the SCP (RMDR) contains information about all employees of the SCP for the entire history of the enterprise, including personal data of medical, dosimetric and professional nature of 65.350 employees of the SCP, of which more than 32.000 people were exposed to chronic technogenic occupational radiation in the range of low doses. The archive of the medical documentation of the Seversk Biophysical Research Center contains 55.569 medical histories of the employees of the SCP, 29.800 outpatient records and 11.953 autopsy protocols.

Results: Employees of the radiochemical, chemical-metallurgical, sublimate and separation industries of the SCP were subjected to combined (external and internal) irradiation, while the personnel of the reactor production were exposed exclusively to external irradiation. Auxiliary production workers were mainly exposed to non-radiation factors. Individual dosimetric control (IDC) of external exposure was carried out for all workers who were in the zone of exposure to external radiation sources. The average accumulated dose of external radiation for employees of the SCP was 28.3 mSv. IDC of internal irradiation was carried out for all workers employed at the production site, where the excess of the regulatory level of the concentration of radionuclides in the air of the working area was detected. The average value of the activity of radionuclides in the urine of SCP workers does not exceed 0.74 Bq. The life status has been clarified for 80.8 % of the employees of the SCP. About 3.500 employees of the agricultural complex have an IDC for internal irradiation from uranium based on the results of a biophysical examination. The life status is established for 75 % of employees of the uranium cohort.

Conclusion: For the first time, a dosimetric characteristic of a cohort of 65.350 workers of the SCP (21 % women) who started work in the period 1950–2010 was given. The cohort of the staff of the SCP is suitable for conducting epidemiological studies in order to establish the risks associated with the impact on the human body of technogenic occupational exposure to IR.