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Radioactive Contamination of Tajikistan and Public Health

#T-1152


Radioactive Contamination of the Environment of Northern Tajikistan and Public Health

Tech Area / Field

  • ENV-EHS/Environmental Health and Safety/Environment
  • ENV-RED/Remediation and Decontamination/Environment

Status
3 Approved without Funding

Registration date
26.04.2004

Leading Institute
Institute of Gastroenterology, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe

Supporting institutes

  • Republican Clinical Center of Oncology, Tajikistan, Dushanbe

Collaborators

  • Uranium Medical Research Center, Inc., Canada, ON, Toronto\nCentral Laboratory for Radiological Protection, Poland, Warsaw\nNagasaki University / Graduate School of Biomedical Sciences, Japan, Nagasaki\nUniversität Hamburg / University Hospital Hamburg-Eppendorf, Germany, Hamburg\nKlinikum der Universitat Munchen, Germany, Munich\nRoyal Liverpool University Hospital, UK, Liverpool\nSeoul National University Hospital / Seoul National University College of Medicine, Korea, Seoul\nPomeranian Medical University, Poland, Szczecin\nHiroshima University / Research Institute for Radiation Biology and Medicine, Japan, Hiroshima\nCooperacion Internacional en Tecnologias Avanzadas, Spain, Madrid

Project summary

The aim of the project is to evaluate the influence of chronic ionizing radiation on health of population inhabiting on radioactively contaminated areas of Northern Tajikistan and development of medicines, biologically active additions (BAD), which are able to decrease the absorption and accumulation of radionuclides and (or) increase resistance of organism to ionizing radiation, using local medicinal food plants.

In order to achieve the set aim it is necessary to solve the following tasks:

1. To estimate and evaluate the external and internal exposure of population living near enterprises for reprocessing of uranium ores and radioactive wastes;


· To determine the possible places and sources of ecological contamination by radioactive substances in the area, which is located close to the enterprises for reprocessing of uranium ores and radioactive wastes;
· To determine concentration of radionuclides (232Th, 238U, 137Cs, 90Sr, 239Pu) in soil, plants and food in the area close to the enterprises for reprocessing of uranium ores and radioactive wastes;
· To determine concentration of radionuclides (232Th, 238U, 137Cs, 90Sr, 239Pu) in blood of population living close to the enterprises for reprocessing of uranium ores and radioactive wastes.
2. To determine and estimate health state and diseases rate of population depending from intensity of radiation background
· Epidemiological analysis of sickness rate of malignant growths and long-period monitoring of contaminated people;
· Estimation of influence of chronic radiation exposure on immune system indicators and ratio of somatic cells in peripheral blood.
3. To investigate factual nutrition of population in contaminated areas and development of measures for its correction.
4. To develop and use new natural biologically active additions (BAD) from local medicinal food plants in order to decrease radiation ratio in human body.

External exposure evaluation of population living close to the enterprises for reprocessing of uranium ores and radioactive wastes is based on measurement of gamma background:

· In radioactive wastes’ repository sites and tailing pits.


· In separate sites of villages.
· Inside of houses.

To determine the level of radioactive contamination in the environment we shall take samples for presence of 90Sr, 137Cs, 238U, 232Th in soil and plants. We shall construct average external doses of external exposure based on these measurements. (M.O. Degteva, 1994). It is known, that the main impact in formation of internal exposure dose belongs to radioactive 90Sr, which is deposited in bones. Except bone-seeking radionuclides 90Sr and 89Sr, vital importance in dose forming has uniformly distributing 137Cs. Reconstruction of internal exposure doses will be based on lifetime measurement of 90Sr in teeth and in whole body using human radiation counter. On the basis of the measurements' results and using the developed age-specific model of 90Sr metabolism (M.M.Kossenko, et al, 1999) we shall calculate average doses of internal exposure for inhabitants of separate age groups of separate villages. Available data on radiation doses is not sufficient for determination of risk group. In this connection, we shall evaluate population exposure dose from inflow of 90Sr and 137Cs in human body with basic food products (milk, grain, potato). We shall determine quantity of absorbed radiation doses for thyroid glands of population. This data will be used for determination of absorbed doses' quantity of thyroid glands for every inhabited locality of northern regions of Tajikistan with the aim to introduce thyroid dosimeter passport system. In order to carry out long-term monitoring of contaminated people and organize epidemiological investigations we shall prepare data on four main directions:

1. Creation and continuous updating of the registry of contaminated people. In Northern Tajikistan such a registry was created in 1965 without using passport system. We shall establish a special group for creation of the registry. Different sources of information will be used: state records, state registries about births and deaths of children from civilian registry offices, replies to inquiries to address offices about real residence data of contaminated people, registry books of villagers, questioning people, which were admitted to dispensary for examination, about contaminated relatives. Data after checking will be inputted in computer database.


2. Gathering information about exposure results (particularly, about cancer development and verification of oncological diagnoses). We shall select zones, where during the whole monitoring period we shall register residence of those people that underwent influence of ionizing radiation, all cases of death and cancer. Monitoring area consists of three administrative districts of Northern Tajikistan. Total population size is about 140 thousand people. In district archives of civilian registry offices we shall make copies of death certificates of all inhabitants of the districts since 1960 until 2003. The main death reasons will be encoded according to International classification of death reasons, 9th revision. In similar way oncological diseases files will be created. Two sources of information will be used: a) notifications about first determined oncological hematological disease, which are registered by static groups of Khujand Oncological Dispensary, Republican Clinical Center of Oncology in Dushanbe, and Sogd Hematology Center – about diagnosis cases of leukemia and solid carcinoma of people living close to the enterprises for reprocessing of uranium ores and radioactive wastes.
3. Control selection. During analysis of radiation effects for the last 30 monitoring years the population group, which have not undergone contamination and exposure but live in the same administrative districts, will be considered as control group. It is so-called regional control. Three control groups will be created, which have similar non-radiation factors (particularly, non-ethnic factor) with other contaminated groups of population. Death rate and level of oncological risk will be determined using the method of register control.
4. Selection of statistical analysis method. Cohort study method will be used for epidemiological analysis of carcinogenic effects. Data will be processed using the program EPICURE (Preston D.L. et al., 1993) and will be grouped according to the following categories: ethical, sex, group, radiation dose, age in the beginning of exposure and at the moment of death. The difference of this program comparing with others is that it allows determining regularities during Pausson's distribution. Besides, it is the only program that was used for risk estimation of people, who survived atomic bombardment.

Particular conditions of populations' exposure (chronic, mainly internal, and in small doses) require biological estimation of its efficiency for prognosis of separate genetical and somatic consequences.

In a number of investigations, researches mentioned increase and dependence from dose of mutant frequency on glukoferine A locus erythrocytes of people, contaminated in the result of radiation disasters (A.V.Akleev and et al, 1998, Kyoizum S and et al, 1995). It is principally important to mention that level of mutant cells in human blood is an integral indicator, which reflects not only the amount of absorbed dose (intensity), but also its distribution in human body, course of reparation processes, inpidual radiosensitivity. We shall study biological dosimetry of radiation effect, particularly, the methods based on frequency analysis of somatic mutations in peripheral blood cells – such as glycophyrine test and state analysis of T – cell receptor. It is important to note that hematosis and immunity are one of the most radiation-sensitive systems of human body, which quantitative and qualitative indicators, in certain degree, may be considered the markers for evaluation of radiation exposure degree. We shall investigate immunity state in order to evaluate health state, course and prognosis of different diseases’ results, and first of all, timorous ones. According to data of many authors (A.B.Knizhnikov, 1988, 1992), contribution of food products in internal radiation exposure ratio is 98-99%. From this: milk - 80%, meat - 10%, potato - 6%, vegetables - 6%, bread - 4%. In this connection arises a problem - how to decrease radiation exposure of population. In our project the aspects of this problem will involve the following: 1) normalization of permissible level in food products and ores’ contamination; 2) control of contamination level in food products; 3) using local medicinal-food plants to develop medicines, products and food addition agents, which are able to decrease absorption and accumulation of radionuclides and (or) to increase resistance of human body to ionizing radiation effect. The employees of the Institute of Gastroenterology and employees of the Republican Clinical Center of Oncology have rich experience in investigation and study of unfavorable environmental factors (radiation and fluorine) on human body. Project participants have been selected on the basis of their experience and knowledge in different fields of science, which altogether ensure the successful implementation of the project and positive solution of set tasks and problems.

Role of foreign collaborators will consist of the following:

1. Information exchange in the course of the project.


2. Provision of comments to technical reports to be sent to ISTC by project participants.
3. Holding joint seminars and meetings.
4. Joint articles with collaborators for publication in scientific journals.


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