"Investigation of the Sources and Mechanisms of the Radionuclides and Toxic Elements Contamination in Syrdarya River Basin at the Territory of the Republic of Kazakhstan" within the Framework of the International Project "Joint International Investigation
Tech Area / Field
- ENV-WPC/Water Pollution and Control/Environment
8 Project completed
Senior Project Manager
Rudneva V Ya
National Nuclear Center of the Republic of Kazakstan / Institute of Nuclear Physics, Kazakstan, Almaty
- Sandia National Laboratories, USA, NM, Albuquerque
Project summaryThe goal of the Project is to study the sources and mechanisms of radionuclides and toxic elements contamination of Syrdarya river basin on the Republic of Kazakhstan territory and the further implementation of the investigation results in solving of the problem of transboundary monitoring and freshwater resources protection of the largest river of South Kazakhstan.
Syrdarya and Amudarya rivers are the life supporting arteries for large region of the central Asia. The following states are involved in basins of these rivers: Tajikistan, Afghanistan, Turkmenistan, and Uzbekistan –Amudarya river; Kirghizia, Tajikistan, Uzbekistan, Kazakhstan – Syrdarya river. Restive epidemiological situation in this region especially in the middle part and lowers of these rivers causes a large anxiety. One of the main reasons of a high level of population sickness rate is considerable contamination of these rivers and dangerous state of ecological and radio-ecological situation in their basins. Such situation was appeared as a result of intensive (different and weakly controlled) economical and industrial activity and because of geological and geochemical peculiarities of this region. One of the more serious aspects of this problem is a weak study of influence on environment of large deposits (more than 15% from world reserves) natural uranium and consequences of technological and industrial works on its prospecting, mining and processing. Beginning from November 2000 four from enumerated countries (Kazakhstan, Uzbekistan, Tajikistan, Kirghizia) came to agreement about carrying out of joint works on study and monitoring of the environment in Syrdarya and Amudarya river basins – it is the International Project "Navruz". The project is planned for two years (ending at September 2002). The collaborator is Cooperative Monitoring Center at Sandia National Laboratories (CMC SNL), USA.
The obtained results of analytic investigations allowed characterizing radio-ecological situation in each country and revealing a number of peculiarities on contamination of these river basins by radionuclides and toxic elements.
The higher level of contamination by natural radionuclides (238U, 235U, 232Th lines) is typical for Syrdarya river basin. Many of studied environmental objects, in spite of radionuclides, are characterized by large content of heavy metals and toxic elements (Cr, Zn, As, Se, Cd, Sb, Hg, Th, U). The place connected with Karatau ridge and its spurs – Syrdarya uranium province – stands out according to this feature. The high selenium concentrations – 1.5-4 mkg/g in soil and bottom sediments (a value of average world concentration value of selenium in sedimentary rocks for comparing is equal 0.6 mkg/g) cause a special anxiety. This element content in water of Syrdarya river exceeds stable a sanitary standard of maximum allowable concentration for drinking water in 2-4 times. The results of investigation of water composition in Badam river flowing into Arys river (inflow of Syrdarya river) are evidence of high concentrations of toxic elements (values of maximum allowable concentrations for drinking water are presented for comparison in parentheses) in mkg/l: As – 320 (50), Se – 8 (1), Mo – 190 (100), Sb – 100 (50), Cd – 30 (1). Such a considerable water contamination is obviously connected with influence of industrial enterprises of Shymkent City. A high level of contamination of Shardaryinsk reservoir bottom has been revealed. It may suppose that this reservoir is a peculiar settling accumulating a considerable part of radionuclides and toxic elements in it, entering with water from Uzbekistan and along the inflow Keles. It was also revealed a contrast increase of the level of radionuclide contamination of bottom sediments in Syrdarya River lower than uranium deposit Shyili. It is possible that it is connected with elaboration of the deposit by the method of underground leaching.
Carried out investigations have revealed separate sources and possible mechanisms of contamination of water of Syrdarya River on the Kazakhstan territory. The similar results are obtained in the rest countries-participants of this Project. It is necessary to continue the works on revealing of other sources-contaminants, study in detail the peculiarities of these sources and mechanisms of entering of all types of contaminants in main life supporting freshwater arteries – Syrdarya and Amudarya rivers. Finally it is necessary to decide the problems on prevention or limitation of this negative process. The scientific community of countries of Central Asia with participation of CMC SNL has elaborated the regional International Program "Joint International Investigations of the Central Asia rivers radioactive contamination investigation for the transboundary control" provided for decision of the problem mentioned above for separate countries of Central Asia.
The present Project "Study the sources and mechanisms of radionuclides and toxic elements contamination of Syrdarya river basin on the territory of the Republic of Kazakhstan" is the important component part of this regional program. The project proceeds wide-ranging investigation (chemical, element and radionuclide water composition, bottom sediments, soil and vegetation) of basins of all drains in Syrdarya river especially from the side of Karatau ridge, revealing of more contaminated drains, sites and objects on the basis of the obtained data. The detailed study of situation (level and character of pollution) in neighborhoods revealed earlier (Shardaryinsk reservoir; uranium deposit Shyily; drains and inflows of Arys, Keles, Badam rivers; industrial center Shymkent and others) sources of contamination of Syrdarya. During the detailed study a special attention will be paid to the territory of underground nuclear explosion "Meridian –3". Study of mechanisms and migration qualities of pollutants (grain-size and sedimentation fractionating, phase separation, separate leaching of soils and bottom sediments; separation of dredges, colloids and ion forms of pollutants in water). Database creation including information on quality and quantity of water and on degree and character of contamination of more ecologically dangerous sites and objects in neighborhoods of Syrdarya and its inflows. Elaboration of scientific well-founded conclusions and recommendations on prevention or limitation of revealed mechanisms of contamination of Syrdarya water by radionuclides and toxic elements. Besides, the Project proceeds a regularly monitoring according to early scheme with following expansion and renewal of control point system, objects and parameters of observation. Besides, the fulfillment of analysis of environmental objects selected on the territory of Kirghizia and partially Uzbekistan is provided.
The sites and objects for investigation will be chosen for carrying out of planned investigated works on the base of retrospective examination and critical analysis of all types of activity and natural phenomenon influenced on ecological and radio-ecological situation of the region. The regularly sampling of river water, bottom sediments, coastal soil and vegetation will be carried out. Sampling will be carried out between March and November during the period of high water level in river connected with snow thawing and normal water level in the river caused inflow of underground water. During sampling the radiometric measurements and measurements defined the main qualitative and quantitative parameters of water will be carried out. At the same time point coordinates of carrying out of measurements and sampling will be defined.
During laboratory works along with methods of radionuclide analysis (a-, b-spectrometry with preliminary radiochemical extraction, instrumental g-spectrometry) the method of chemical, activation and X-ray fluorescent analysis as well as mass spectrometry with AES-ISP. The uranium isotope content in separate soil samples and bottom sediments will be investigated by means of mass-spectrometry method.
The new results on contamination by radionuclides and toxic elements of Syrdarya river basin including inflows will be received as a result of investigations within the framework of the Project. The more polluted sites and objects will be revealed and characterized from the point of view of potential and real dangerous. Database including all information on ecological and radio-ecological state of Syrdarya river basin will be created. Scientific well-founded recommendations and offers concerning the control (radio-ecological monitoring system) as well as limitation of all possible mechanisms of pollutant entering in Syrdarya river will be fulfilled. These recommendations will be promote to decision of the problem of transboundary control and water storage protection as well as improvement of ecological situation in zone of Aral region.
The project works will be performed by the high-qualified staff-physicists, chemists, engineers and technicians with large experience in nuclear physical methods of analysis, radiochemistry, mass spectroscopy instrument-making, nuclear techniques, data processing and numeral simulation programmers.
For successful Project fulfillment the role of foreign collaborator – CMC SNL – is very important. It includes first of all coordination of investigations in accordance with regional Program "Joint International Investigations of the Central Asia rivers radioactive contamination investigation for the transboundary control"; participation in making of work plans on the Project; help in technical means and equipment acquisition necessary for successful realization of project tasks; consultative and technical help in database creation, participation in analytic works for interlaboratory comparison; organization and carrying out of joint working meeting and seminars; discussion of final results of the Project.
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