Assessment of the radiological impact of gamma and radon dose rates at former U mining sites in Central Asia
Introduction
Uranium ore mining and processing started in the former Soviet Republics of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan after the Second World War and lasted for half a century. Extensive mining and milling activities resulted in large amounts of uranium tailing materials and waste rock deposits, often dumped in inhabited areas or in their close vicinity. Both materials may have a potential radiological impact on the environment and on the local populations.
A NATO Science for Peace project RESCA (Radioactivity Environment Security Central Asia) and a Joint Norwegian–Kazakhstan–Kyrgyzstan–Tajikistan (JNKKT) project to secure the effective management of uranium industry wastes in the Central Asian republics of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan were initiated in 2006/2007 in order to prevent health and environmental damage. The participating institutions included Jožef Stefan Institute, Slovenia; Norwegian University of Life Sciences and Norwegian Radiation Protection Authority; Joint Stock Company Volkovgeologiya and Al-Farabi Kazakh National University from Kazakhstan; Chu Laboratory of Ecology, Kyrgyzstan; State Owned Company Vostokredmet, Tajikistan; and the Institute of Nuclear Physics, Uzbekistan.
The objectives of the NATO RESCA project included:
- •
the characterization of the source-terms and determination of local radioactive contamination in selected uranium tailing sites in Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan;
- •
radiation dose and impact assessment; and
- •
identification of appropriate mitigation/remediation countermeasures.
The objectives of the Joint Norwegian–Kazakhstan–Kyrgyzstan–Tajikistan project (JNKKT) were: to assess long term consequences from radioactive and trace metal contamination associated with uranium mining and tailing at selected sites, especially at sites where run-off to rivers may significantly influence drinking water and river qualities, with the following sub-goals:
- •
to utilize state-of-the-art technology for assessing potential mobility and ecosystem transfer;
- •
to perform dose and impact assessments for man and the environment;
- •
to evaluate the needs for countermeasures; and
- •
to strengthen the scientific competence in Kazakhstan, Kyrgyzstan and Tajikistan with respect to sampling strategy, measurements, ecosystem transfer models and environmental impact assessments, and the framework/infra-structure with respect to management of radiation protection.
In the NATO RESCA study, an assessment of the radiological situation was conducted at former uranium mining and processing sites in the Central Asian countries of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan. To make a reliable assessment of current radiation doses received by the resident population living at or in the close vicinity of the uranium tailings and radioactive waste rock deposits, gamma dose rates, indoor radon (222Rn) and thoron (220Rn) measurements were carried out, including several measurements of 226Ra, 210Pb and 210Po in selected environmental samples at some of the investigated uranium legacy sites (UMB/JSI Draft Report, 2011).
At all investigated sites, mine rock deposits and uranium mill tailings were located within or in the close vicinity of residential areas. At all investigated sites, members of the resident public might have used radioactive materials, i.e. mine rock deposits for building and street coverings, and tailings residues as material for construction purposes, which could significantly contribute to elevated radiation doses in the living (indoor) environment.
The measurements started in spring 2006 and concluded in summer of 2009. The study aimed at a reliable assessment of radiation doses due to indoor 222Rn/220Rn and gamma exposure to ionizing radiation at the investigated uranium legacy sites in Central Asia. A preliminary radiological risk assessment for the resident public was made on the basis of the results obtained. A total of 19 field visits and expeditions were performed during the period.
Section snippets
Description of the sites investigated
The locations of the sites investigated within the NATO SfP RESCA project and the Joint collaboration between Norway, Kazakhstan, Kyrgyzstan and Tajikistan (JNKKT) project are shown in Fig. 1.
Gamma dose rates
In Kurday, the gamma dose rates in air were measured at the Pit Lake and in the area covered by waste rock piles. Based on a total of 40 measurements, the gamma dose rate ranged from 0.14 to 0.95 μGy/h 1 m above ground and 0.15–1.14 μGy/h at ground level. The readings obtained with two different field survey scintillation counters were in good agreement. In general, the gamma dose rates varied according to the site, with peak concentrations identified at the pit lake and at the top of the
Conclusions
The U legacy sites studied in Central Asian countries of Kazakhstan, Kyrgyzstan, Uzbekistan and Tajikistan represent sources of potential contamination of the living environment by naturally occurring radionuclides. The majority of legacy sites are only partly or not at all remediated, which allows unrestricted access to the sites by the resident public. The unfavorable radiological situation is to a large extent a consequence of inappropriate management of the former U sites, mainly due to the
Acknowledgments
The authors gratefully acknowledge the assistance of the NATO SfP programme in funding the RESCA project. Technical support in the field missions, overall co-operation, collaboration and assistance, particularly of young specialists involved in the NATO RESCA and to the Norwegian Ministry of Foreign Affairs for funding the JNKKT projects is also highly appreciated.
References (13)
- et al.
Assessment of the radiological impact of gamma and radon dose rates at former U mining sites in Kyrgyzstan
Journal of Environmental Radioactivity
(2013) - et al.
Environmental impact assessment of the radionuclides and trace elements at the Kurday U mining site, Kazakhstan
Journal of Environmental Radioactivity
(2013) - et al.
Environmental Impact Assessment of radionuclide and metal contamination at the former U sites Taboshar and Digmai, Tajikistan
Journal of Environmental Radioactivity
(2013) Radiation Protection Against Radon in Workplaces Other than Mines
(2003)1990 recommendations of the International Commission on Radiological Protection
Annals of the ICRP
(1991)Annals of the ICRP, Publication 103, the 2007 Recommendations of the International Commission on Radiological Protection
(2007)
Cited by (29)
Societal aspects of NORM: An overlooked research field
2022, Journal of Environmental RadioactivityThe effect of water exchange on the leaching of alum shale
2020, Applied GeochemistryTrace elements and ALAD gene polymorphisms in general population from three uranium legacy sites – A case study in Kyrgyzstan
2020, Science of the Total EnvironmentCitation Excerpt :These studies have focused on environmental impact assessments of radioactive and chemical contaminants, and their results are being used for adopting efficient countermeasures against environmental pollution. Considerable analytical data about radioactive and chemical pollutants have been obtained, and radiation doses and related health risks for resident populations as well as pollution levels of chemical contaminants in the living environment have been assessed (Stegnar et al., 2013; Salbu et al., 2013; Lind et al., 2013; Skipperud et al., 2013). Individual doses of ionizing radiation were slightly to moderately elevated in comparison with those in a U clean environment; however, these did not pose health-related radiation risks that would require interventions.
Challenges associated with the behaviour of radioactive particles in the environment
2018, Journal of Environmental RadioactivityCitation Excerpt :Lind and co-workers utilised micro-analytical techniques to identify radioactive particles (submicron to several hundred microns) and fragments containing U and a range of heavy metals in dust samples, in mineral grains and mineral fragments from the abandoned Former Soviet Union U mining sites Kurday, Kazakhstan, Kadji Sai, Kyrgyzstan (Fig. 6) and Taboshar, Tajikistan. Following the cold war, extensive U mining and production took place at selected sites in Central Asia as a vital part of the nuclear weapon program in the former Soviet Union (Stegnar et al., 2013). The full industrial cycle of U recovery and processing of U ores have been undertaken in this region for about 50 years.
Monitoring of uranium concentrations in water samples collected near potentially hazardous objects in North-West Tajikistan
2018, Journal of Environmental RadioactivityRapid and highly efficient removal of Eu(III) from aqueous solutions using graphene oxide
2017, Journal of Molecular Liquids