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Studies on the health effects
of radiation exposure are conducted jointly by U.S.
and Russian scientists at Mayak and the Southern Urals
Biophysics Institute in Ozersk and at the Urals Research
Center for Radiation Medicine in Chelyabinsk. U.S. organizations
currently involved in the studies are:
- Georgetown University;
- National Cancer Institute;
- Pacific Northwest National Laboratory;
- University of Illinois at Chicago; and
- University of Utah.
Russian organizations leading the studies are:
- Mayak Production Association;
- Southern Urals Biophysics Institute; and
- Urals Research Center for Radiation Medicine.
The program is organized into three directions: community,
worker, and emergency response.
Direction
1: Community Health Effects Research
The major goal under this Direction is to analyze
the carcinogenic risk of radiation exposure. For this
purpose, 3 projects are being conducted:
- Project 1.1, Techa River Population Dosimetry;
- Project 1.2b, Techa River Population Morbidity;
and
- Project 1.4, Reconstruction of Dose to the Residents
of Ozersk.
Project 1.1: Techa River
Population Dosimetry
Principal Investigators:
R.F.: Marina
Degteva, Urals Research Center for Radiation Medicine
U.S.: Lynn Anspaugh,
University of Utah
Brief Description: This dose reconstruction
project is to develop improvements in the existing Techa
River Dosimetry System 2000 for the members of the Extended
Techa River Cohort (ETRC) by reducing the uncertainty
of the doses, validating the doses, determining the
feasibility of reconstructing doses from medical exposures,
and reconstructing doses from other sources of radiation
exposure, such as the East Urals Radioactive Trace and
resuspension from deposits in Lake Karachai. The specific
goal of this project is to update the reconstruction
of external and internal radiation doses for approximately
30,000 individuals in the ETRC for use in companion
epidemiologic studies of radiogenic leukemia and solid
cancers (see below Project 1.2b, Techa River Population
Morbidity).
Results to date: The specific aim of the completed
phase of this project was to enhance reconstruction
of doses for the ETRC cohort members. The database of
preliminary village-average doses was expanded and upgraded
to individualized doses and the uncertainty in the reconstructed
doses was evaluated for the first time.
Projected end date: September 2012.
Project 1.2b: Techa River
Population Morbidity
Principal Investigators:
R.F.: Alexander
Akleyev, Urals Research Center for Radiation Medicine
U.S.: Faith Davis, University of Illinois at Chicago
Brief Description: This epidemiologic study
is designed to assess carcinogenic effects among populations
exposed to offsite releases of radioactive materials
from the Mayak nuclear facility. Discharges of radioactive
wastes into the Techa River during the period 1950-1956
resulted in radiation exposures of the inhabitants of
the riverside villages for whom the river was the principal
source of water. This is the first study of cancer morbidity
in the extended Techa River cohort (ETRC). It is a companion
study to Project 1.1, Techa River Population Dosimetry,
and to Techa River Population Mortality, sponsored by
the U.S. National Cancer Institute. The aim of Phase
III is to extend the follow-up of cancer incidence among
the members of the ETRC and use new epidemiological
and dosimetric data from Project 1.1 to assess radiogenic
cancer risk.
Results to date: Preliminary results from this
study indicate an increased incidence of leukemia and
stomach cancer in the exposed population.
Projected end date: September 2014.
Project 1.4: Reconstruction
of Dose to the Residents of Ozersk
R.F.: Yuri Mokrov, Mayak
U.S.: Lynn Anspaugh,
University of Utah
Brief Description: Phase II of this dose reconstruction
project is to reconstruct time-dependent individual
radiation doses to the residents of the city of Ozersk,
Russia, and the surrounding area from atmospheric releases
of radionuclides from nuclear weapons production activities
at Mayak from 1948 to present. Focus will be on the
emission of I-131 and dose to the thyroid glands of
children. Data will support the epidemiologic study
of thyroid cancer in children sponsored by the National
Cancer Institute. This should help resolve the dichotomy
between the studies at Hanford (no observed effect)
and Chernobyl (large effect). The data also will determine
whether these emissions are a confounding factor in
the evaluation of radiogenic cancer risk in other groups
under study, such as the Extended Techa River Cohort
(Project 1.2b) and the Mayak worker cohort (Project
2.2).
Results to date: The Phase I feasibility study
was completed on March 31, 2004 and a final report was
prepared. For the first time, an estimate of the atmospheric
stack releases of I-131 was prepared by month from the
two fuel-processing plants.
Projected end date: September 2010.
Project 2.2: Mayak
Worker Mortality
Principal Investigators:
R.F.: Mikhail Sokolnikov, Southern Urals Biophysics
Institute
U.S.: Ethel Gilbert, National Cancer Institute
Brief Description: This epidemiologic study
is designed to obtain quantitative estimates of carcinogenic
risks from both protracted external exposure and from
internal exposure to plutonium based on analyses of
data from the Mayak worker cohort. The cohort consists
of 26,000 workers first employed at any time between
1948 and 1982. Vital status is known through 2000. Risks
of cancers of the lung, liver, and bone are being expressed
as functions of doses to these organs and of potential
modifying factors such as sex, time since exposure,
and age at exposure. In addition, researchers will investigate
whether risks of cancers of sites other than lung, liver,
and bone are related to external dose and to plutonium
exposure. Uncertainties in risk estimates that are developed
will be quantified. In order to meet these objectives,
further improvements in the data are being implemented.
These include the continual updating of follow-up and
the collection of further data on smoking from medical
records. The results of this study are likely to enhance
our understanding of protracted radiation exposure risks
to humans and provide definitive data for the improvement
and validation of radiation protection standards.
Results to date: This is the first study to
demonstrate a statistically significant association
between occupational exposure to plutonium and bone,
lung, and liver cancer. These analyses were performed
using the Mayak worker Doses 2000 database. Now that
the Project 2.4 dosimetrists have completed the "Doses
2008" database, Project 2.2 researchers will analyze
the data using the most recent dose estimates and compute
new cancer risk estimates linked to radiation dose.
Projected end date: September 2014.
Project 2.4: Mayak Worker
Dosimetry
Principal Investigators:
R.F.: Evgeny Vasilenko (External Dosimetry Team Leader),
Mayak and Anotoly Schadilov (Internal Dosimetry Team
Leader), Southern Urals Biophysics Institute
U.S.: Robert Scherpelz (External Dosimetry Team Leader),
Pacific Northwest National Laboratory, and Daniel Strom
(Internal Dosimetry Team Leader), Pacific Northwest
National Laboratory.
Brief Description: This dose reconstruction
project is to establish a computerized database of individual
internal and external radiation doses and uncertainty
about those doses for each member of the 26,000 Mayak
worker cohort under study in Project 2.2, Mayak Worker
Mortality. The work product will be an electronic database
containing updated individual dose estimates by year
called "Doses 2013." As a result, improved doses for
risk assessment analysis of causes of health effects
from radiation exposure will be available. These data
are also being used for other projects in Direction
2. This project is perhaps one of the most important
of the 6 current projects within the Russian Health
Studies Program. Without good dosimetry data, epidemiologists
and biostatisticians will not be able to assess radiation-induced
cancer risks from exposure to gamma, neutron, and alpha
radiation. The Mayak worker cohort under study has the
largest number of individuals and the highest chronic
radiation exposures of any known population on earth.
Approximately one-fourth of the exposed workers were
women. Detailed health and exposure records are available
at Mayak, thereby facilitating radiation health effects
research.
Results to date: In addition to providing the
dosimetric data for Project 2.2, Mayak Worker Mortality,
this project has enhanced the understanding of plutonium
metabolism in the human body and improved the biokinetic
models for assessing dose from plutonium uptakes. These
outcomes will be of direct benefit to DOE in improving
the determination of dose to DOE workers from plutonium
exposure. Improved doses have been calculated for a
fraction of the group of workers. Dose calculations
and uncertainty analysis of the doses continues. The
Mayak worker dosimetry database "Doses 2005" was completed
in 2005. The "Doses 2008" database was completed
in 2009. Project 2.2 researchers will analyze the data
using the most recent dose estimates and will produce
revise radiation cancer risk estimates by September
2011.
Projected end date: September 2013.
Project
2.8: Mayak Worker Tissue Repository
Principal Investigators:
R.F.: Evgenia Kirillova, Southern Urals Biophysics
Institute
U.S.: Christopher Loffredo, Georgetown University
Brief Description: The aim of this project
is to establish and maintain a state-of-the-art tissue
repository designed to serve as a resource for studies
of the effects of protracted internal and external radiation
exposure on human health. The repository is located
at the Southern Urals Biophysics Institute in Ozersk.
It includes samples of archival autopsy tissues from
940 registrants, samples of surgical tissues from more
than 655 individuals, and samples of blood and its components
from about 4,012 Mayak workers and residents of Ozersk,
supernatant and sputum cells from individuals, buccal
cells from 1,500 Mayak workers, and genetic material
(DNS from blood) of 138 Mayak workers' family triads.
The storage conditions of the biosamples in the repository
were designed to provide optimal long-term preservation
of tissue samples. In conjunction with medical, occupational,
and dosimetry information, data collected in the repository
are used in molecular epidemiology studies. Such studies
can be used to establish an association between disease
and radiation exposure in individuals.
Results to date: Samples of tumor and other
tissues for 155 registrants were delivered to the U.S.
researchers working on several projects in the Russian
Health Studies Program, i.e., Project 2.5, Plutonium
Microdosimetry in the Lung, Project 2.6, Molecular Markers
of Lung Cancer, and Project 2.7, Radiation Biomarkers.
Without these samples, completion of Projects 2.5, 2.6,
and 2.7 would not have been possible. Methods of transportation
of tissue samples from Russia to other countries by
international air mail have been tested and implemented.
A website in both Russian and English describes the
contents of the repository and the procedures for researcher
access to the contents. Further collection and storage
of tissue samples in optimal conditions and intensification
of efforts to inform scientists worldwide on the established
repository and its biosamples are underway.
Projected end date: September 2012.
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