The purpose of the project. The purpose of this project is to conduct an eco-analytical monitoring for PCBs in the areas where PCB-containing capacitors are exploited and stored, and to develop optimal and environmentally safe methods for the neutralization of PCBs.
Relevance to the field of research so far. A great deal of efforts was put in the identification of PCB problems and their solution in Kazakhstan within various state programs and projects [1-6]. The results of the research so far have made it possible to compile the register of PCB-containing equipment locations and PCB-contaminated territories, to determine preliminarily the volumes and technologies for neutralization of PCBs, suitable for the conditions of Kazakhstan, for technology suppliers and for the cost of neutralization of PCBs in the Republic of Kazakhstan. The main contaminated area is the territory of the Ust-Kamenogorsk Condenser Plant (UKCP) and its storage pond, where about 80% of the PCBs of the republic are located. In the territory of ??UKCP, an area of ??up to 1,200 hectares of medium-contaminated soils has been identified [2].
The authors of this project carried out analytical studies of water and sediments samples of the Irtysh River, soils, as well as biota for the quantitative assessment of PCBs in the studied samples, within the framework of the NATO project SfP 983931 "Sustainable Management of Toxic Pollutants in Central Asia: to the Regional Ecosystem Model for Environmental Protection" [5-8, 18-19]. PCBs were identified in all analyzed samples. The content of 2,2',5,5'-tetrachlorobiphenyl in the river water near UKCP was 18.062 ?g/mL, in addition traces of hepta- and hexachlorobiphenyls were found [6-8].
From 2013 to 2015, the authors of this project won a grant from the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (No. 2611/ГФ3-14-OT) to carry out research on the topic: "Development of new catalytic systems based on gel-immobilized and polymer-protected metal nanoparticles for the reductive dechlorination of polychlorinated biphenyls" and carried out a number of works on the study and assessment of the pollution of the environmental objects with PCBs in Ust-Kamenogorsk, as well as various activities to attract public attention, the scientific community and the local administration to the environmental problems of the region [5-8, 19]. It was established that the highest levels of soil and sediment contamination were detected in the nearby territory of UKCP JSC and storage pond, i.e. in places of operation of capacitors filled with dielectric liquids based on PCBs and a buried layer of soil with TCB residues. Based on data from industrial enterprises and territorial environmental authorities, the authors of the project conducted an inventory of PCBs and PCB-containing equipment [8].
Within the framework of the ISTC K-1356 project "Marketing research of technologies developed at the Nuclear Energy Institute of the NNC RK", employees of the NNC RK RSE carried out marketing research and developed a business plan for the project "Creation of a complex for processing and storage of polychlorinated biphenyls at the Institute of Atomic Energy and the Radiation Safety and Ecology Institute of NNC RK ".
Regarding the methods for POPs neutralization, a number of authors have proposed a method for liquid-phase hydrodechlorination of chloroaromatic compounds using a catalyst containing palladium with noble metal additions [9]. However, this development relates to the process of the catalytic liquid-phase dechlorination of chlorobenzene, hexachlorobenzene and tetramethyl ammonium chloride and cannot be used for neutralization of PCBs. Within the ISTC program, projects No. 3155 "Neutralization of sovtol", No. B-1872 "Plasma chemical treatment of organic waste" and No. B-1872 "Conversion of organic wastes into usable synthesis gas" were implemented.
Within the framework of the project No. 2611/ГФ3-14-OT we have developed a catalytic system based on mono- and bimetallic nanoparticles of transition and noble metals, stabilized by polymers on a mixed carrier (zinc oxide and coal), for the hydrodechlorination of chlorobenzene [10-13]. Some catalysts have also been tested for the hydrodechlorination of PCBs. The obtained results clearly show the high efficiency of the synthesized catalytic systems for neutralization of halogen-organic substances, including PCBs. The obtained results are prerequisites for further deep research of this problem, which was planned within the framework of this project.
When analyzing the regulatory framework for PCBs monitoring in various objects, the following conclusions can be drawn: the methods for determining PCBs in a limited number of objects (drinking, natural and waste water, soil, sediments, slimes, natural and technogenic wastes) are regulated [26-32]. There are no standardized methods for controlling PCBs in agricultural products and food products; the limit of quantification of PCBs in regulatory documents is at the level of not lower than 0.01 ?g/dm3. However, to ensure environmental safety, it is necessary to monitor the content of PCBs at the background level. To conduct a full-scale and reliable ecoanalytical control of the PCB content in various objects, it is necessary to create highly sensitive and specific measurement techniques, both screening (GC-ECD) and arbitration (GC-MS-MS).
The impact of the proposed project on the progress of this field. The successful completion of this project will give a powerful impetus to the development of a systemic approach for the processing of PCBs, taking into account their distribution in environmental objects, in condensers and transformers using catalytic systems with low noble metals content operating under mild conditions. The developed catalysts exclude the formation of dioxin type compounds, which are even more toxic, compared to the recycled waste. The use of the developed catalysts can give an additional significant socioeconomic effect as a result of a significant reduction in the content of noble metals (by two or three orders of magnitude compared to conventional catalysts) and will contribute to the improvement of the environmental situation in Kazakhstan as a result of the processing of excessively produced and used halogenated by-products and POPs .
