Speciation of Uranium in Bottom Sediments of Reservoir V-17, Mayak Production Association

The radiochemical analysis of plutonium activity in urine is the main method for indirect estimation of doses of internal exposure from plutonium incorporation in professional workers. It was previously shown that late-in-life acute diseases, particularly those that affect the liver, can promote accelerated rates of release of plutonium from the liver with enhanced excretion rates. This initial study examines the relationships of some chronic diseases on plutonium excretion as well as the terminal relative distribution of plutonium between the liver and skeleton. Fourteen cases from former workers at the Mayak Production Association (Mayak PA) who provided from 4–9 urine plutonium bioassays for plutonium, had an autopsy conducted after death, and had sufficient clinical records to document their health status were used in this study. Enhanced plutonium excretion was associated with more serious chronic diseases, including cardiovascular diseases and other diseases that involved the liver. These chronic diseases were also associated with relatively less plutonium found in the liver relative to the skeleton determined by analyses conducted after autopsy. These data further document health conditions that affect plutonium biokinetics and organ deposition and retention patterns and suggest that health status should be considered when conducting plutonium bioassays as these may alter subsequent dosimetry and risk models.

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Incidence trend for colorectal cancer in the cohort of workers exposed to ionizing radiation

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2020-13-3-18-24 ◽

2020 ◽

Vol 13 (3) ◽

pp. 18-24

Author(s):

G. V. Zhuntova ◽

T. V. Azizova ◽

M. V. Bannikova ◽

T. P. Zavarukhina

Keyword(s):

Colorectal Cancer ◽

Ionizing Radiation ◽

Cancer Incidence ◽

Occupational Exposures ◽

Production Association ◽

Malignant Neoplasms ◽

Study Cohort ◽

Median Dose ◽

Mayak Production Association ◽

Colorectal Cancer Incidence

Colorectal cancer is one of the most common malignant neoplasms. Main causes inducing this type of cancer are factors related to the life style and occupational exposures to chemical agents. Some studies demonstrated an association of colorectal cancer incidence and mortality with ionizing radiation. The aim of the present study was to assess the trend in colorectal cancer incidence in a cohort of nuclear workers employed at the Mayak Production Association who had been exposed to ionizing radiation over prolonged periods. The cohort comprised 22,377 workers (25% of females) employed at one of the main plants (reactors, radiochemical and plutonium production plants) of the Mayak Production Association in 1948-1982 who had been externally exposed to gamma rays (cumulative absorbed colon doses were 0–5.85 Gy with the corresponding median dose of 0.16 Gy) and those who had inhaled aerosols containing plutonium particles had been also internally exposed to alpha radiation (cumulative absorbed colon doses were 0–0.18 Gy with the corresponding median dose of 0.0002 Gy). Over the period of 1948–2018, 239 colon cancers and 186 rectum cancers were diagnosed in the study cohort. The incidence of colorectal malignancies among workers of the study cohort was shown to increase with age above 50. Age-standardized incidence rates were higher in males than in females. The time trend analysis of age-standardized rates of colorectal malignancies among workers of the study cohort was performed using a spline regression. The trend of age-standardized rates of colorectal cancer incidence in the Mayak Production Association workers over the analyzed period was nonmonotonic. In general, the average annual percent change of incidence growth for colon cancer was less than 0.1% (for both sexes), while the corresponding estimates for rectum cancer were 1.1% in males and 30.3% in females. To assess the effect of occupational radiation exposure on the incidence of colorectal malignancies, a radiogenic risk analysis that would take into account non-radiation risk factors should be performed.

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