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7ФИЗИКО-МАТЕМАТИЧЕСКИЕ НАУКИ UDC 544
RADIOECOLOGICAL MONITORING OF THE SURROUNDING AREAS OF THE
BAKU OIL REFINERI
Doctor chemical sciences KH.F.MAMMADOV1, master's student N.V.ALEKBEROVA2, junior researcher H.N.SHIRALIYEVA1, engineer E.I.MEHTIYEV1 1Institute of Radiation Problems of the Ministry of Science and Education of the
Republic of Azerbaijan, 2Azerbaijan State Oil and Industry University
The concentration of minerals and radionuclides in soil samples taken from the upper layers of the soil Outside of the Oil Refinery named after H. Aliyev, as well as in other soil samples taken from other regions of Baku, is 10-60% lower than in samples taken from deeper layers from outside of the Oil Refinery. The concentrations of modified heavy petroleum products in the deep layers of the soil range from 2% to 40%, while in the soil samples taken from the upper layers there are onlu the trace amounts of petroleum products. These facts testifies to the imported nature of the upper part of the soil surrounding the territory of the Oil Refinery named after H. Aliyev. The measurement results show that the values of the total radiation in the surrounding territories of the Oil Refinery (absorbed dose rate equal to 0.03-0.12 ^Zv/h) do not exceed the directive permissible value for ionizing radiation (0.12 nZv/h).
Keywords: soil samples, radionuclides, minerals in samples, radiation, absorbed dose, modified petroleum products.
INTRODUCTION
Anthropogenic factors that have arisen with the development of science and technology are the causes of pollution of ecosystems by organic and inorganic liquid and solid chemicals, oil products, poisonous gases, radionuclides and other wastes, disturbances in the equilibrium state of the cycle processes formed over billions of years of evolution on our planet [1-3].
The established cycle, the circulation of substances and energy, the balance in ecosystems is to a certain extent in a state of self-healing, resistance to relatively small changes in structural components. However, the self-healing ability of an ecosystem is not infinite, and uncontrolled use, the introduction of large-scale technological production processes, sooner or later, can undermine not only the ability to self-heal, but can lead to the destruction of the established balance in the exchange and circulation of matter and energy on the planet. The influence of these negative factors on the atmosphere and hydrosphere of the planet continues and this leads to a change in the intensity and modification of natural disasters characteristic of the planet.
Growth rates of climate change, melting of glaciers, depletion of drinking water sources, air and water pollution, a slight decrease in the concentration of oxygen, ozone, forest fires, pollution of soil, atmosphere and oceans toxic chemicals, partial degradation of habitats and biodiversity on our planet over the past century should be a wake-up call for humanity.
It is necessary to prevent as soon as possible all processes that can lead to man-made disasters, to minimize the implementation of projects that provide for global changes in ecosystems, associated with significant changes in the landscape, flora, fauna and water bodies. The widespread transition to waste-free technologies, renewable and hydrogen energy can guarantee a long, strong and safe life on Earth [4-6].
EXPERIMENTAL PART
Minerals, heavy metals and radionuclides were analyzed using X-ray fluorescence (EXPERT-3L - Ukraine, XRF - USA), atomic absorption (AA-6800 - Shimadzu, Japan) and gamma spectrometry (Canberra with HPGe detector - USA). Thermo Eberline R020 SI dosimeter (Thermo Electron Co., USA) used to carry out systematic radiometric measurements and monitoring. Determination the presence of alpha, beta, gamma, neutron, X-ray types of radiation and the intensity of radiation were assessed using a "PRM-470CG" gamma counter (Tesla Systems Ltd., USA), radiometer-dosimeter "InSpector 1000" (Canberra Co., USA-France), radiometer-counter of alpha, beta, gamma, neutron radiation "Radiagem 2000" (Canberra Co., USA -France), gamma-neutron radiometer-dosimeter ISP-RM1401K-01 IP65 (POLIMASTER, Minsk, Belarus). The radiometer "IdentiFINDER" (Thermo Scientific Co., Germany-USA) and "GR-135 Plus" (Exploranium Co., USA-Canada) used for the determination of natural radioactive isotopes or trace amounts of nuclear materials[7-10].
RESULTS AND DISCISSION
Soil samples taken from the surrounding areas of the Baku oil refinery were first washed with organic solvents. Then the soil residue was extracted with weak acid and alkaline solutions. The soil residue after this stage was washed with distilled water. All the extracts were filtered, the obtained partially transparent-colorless solution was spun in a centrifuge at a speed of 5000 rpm, the obtained clear solutions were fully evaporated, and finally the soil minerals were taken in the form of a mixture of white salts, and physicochemical analyzes of salts were performed.
The obtained results are shown in Table 1.
Table 1
Concentrations of components in the composition of soil samples taken from outside of the
Oil Refinery named after H.Aliyev.
Regions Components, mg/kg
Sulfates Chlo -rides Na; K Ca /all carbonates/ J Sr NO3; NO2 Fe; Mn Z n As
Outside of the Oil Refinery named after H.Aliyev 210 327 136; 5050 3640 1,2 24 44; 1,7 .55; 9 2, 2 0,00 2
The results of radiometric measurements and the activity of radionuclides in soilsamples taken from Outside of the Oil Refinery named after H.Aliyev are shown in Table 2.
According to the "Law of the Republic of Azerbaijan on Radiation Safety of the Population", the permissible value of the average annual dose for the population is 1 mZv, which is equivalent to the absorbed dose rate of 0.115 or approximately 0.12 ^Zv/h.
The results shown in tables 1 and 2 show that the concentration of minerals and radionuclides in soil samples taken from the upper layers of the soil Outside of the Oil Refinery, as well as in other soil samples taken from other regions of Baku, is 10-60% lower than in samples taken from deeper layers from Outside of the Oil Refinery named after H. Aliyev [9]. This fact shows that the upper layer of the soil of the surrounding territories of the plant are imported. After extraction of soil samples taken from Outside of the Oil Refinery named after H.Aliyev with n-hexane and chloroform, it was established that the concentrations of modified heavy petroleum products in the deep layers of the soil range from 2% to 40%, while in the soil samples taken from the upper layers there are onlu the trace amounts of petroleum products. This fact testifies to the imported nature of the upper part of the soil surrounding the territory of the Oil Refinery named after H. Aliyev.
Table 2
The results of radiometric measurements and the activity of radionuclides in soil
samples taken from outside of the Oil Refinery named after H.Aliyev.
Regions (background -/Zv / h; alpha ray Bqeq / sm2) Isotopes, Bq / kg
uNa 22 19K 40 26Fe6 0 27Co57 , 27Co60 30Zn 65 38Sr9 1 50SnU 3 ' 50Sn12 6 63Eu15 2 ^Eu15 4 88Ra22 6 90Th22 8
Outside of theOil Refinery named after H.Aliyev (0,05; 0) 1,0 1,7 0,95 0,82 0,16 0,56 0,49; 0,48 0,57; 0,42 0,88 0,06
Table 2 shows the results of measuring the total radiation in the surrounding territories of the Oil Refinery, an assessment of the types of radioactive radiation and a studyof the distribution of radionuclides in the soil. The measurement results show that the values of the total radiation in the surrounding territories of the Oil Refinery (absorbed dose rate equal to 0.03-0.12 ^Zv/h) do not exceed the maximum permissible value (PV = 0.12 ^Zv/h).
In this work, at the preparation of samples for the separation of heavy metals from soil samples, weak solutions of acids and alkalis were used. After filtration andevaporation of these extracts in the obtained minerals the total activity of radioactiveelements was found to be identical to the activity of radionuclides in the studied initialsoil samples. Therefore, a conclusion was drawn on the effectiveness of cleaning contaminated soil with radioisotopes by sequentially treating it with solutions of weakacids and alkalis.
For the purification of heavy metals and radionuclides, as well as oil products from water cakes of contaminated soil samples, we also used methods of radiolytic stitching them onto the surface of finely chopped wood shavings.
Therefore, we developed a new method using varying (depending on the degree of soil contamination) amounts of acidic and alkaline solutions for the separation of heavy metals and radionuclides from samples of contaminated soils. In addition to efficiency and profitability, the correct application of this method allows you to save soil fertility.
CONCLUSION
The concentration of minerals and radionuclides in soil samples taken from the upper layers of the soil Outside of the Oil Refinery, as well as in other soil samples taken from other regions of Baku, is 10-60% lower than in samples taken from deeper layers from Outside of the Oil Refinery named after H.Aliyev. The concentrations of modified heavy petroleum products in the deep layers of the soil range from 2% to 40%, while in the soil samples taken from the upper layers there are onlu the trace amounts of petroleum products. These facts testifies to the imported nature of the upper part of the soil surrounding the territory of the Oil Refinery named after H.Aliyev. The measurement results show that the values of the total radiation in the surrounding territories of the Oil Refinery (absorbed dose rate equal to 0.03-0.12 ^Zv/h) do not exceed the directive permissible value for ionizing radiation (PV = 0.12 ^Zv/h).
Therefore, we developed a new method using varying (depending on the degree of soil contamination) amounts of acidic and alkaline solutions for the separation of heavy metals and radionuclides from samples of contaminated soils. In addition to efficiency and profitability, the correct application of this method allows you to save soil fertility.
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