South Ural Region Research Articles

90Sr Concentration in Cow Teeth from South Ural Region, Russia, Using Monte Carlo Simulation

The Imaging Plate (IP) technique which uses the Monte Carlo code, MCNP, to convert IP response to 90Sr concentration with varied thickness of the standard source has been proposed in this study. In order to verify the validity of simulation calculation in the proposed method, the radial distribution of IP signal has been compared between calculation and experiment. The result is, they are in good agreement. The proposed method has been applied to a cow tooth from the territory contaminated by radioactivity after the accident in the Mayak facility in the South Ural, Russia. Two samples have been prepared from the tooth, i.e., a thin sample of 1.2+/-0.2 mm in thickness and a thick sample which is a half of the tooth. The IP response has been evaluated for the thick sample using experimentally made standard sources, and multiplied by a modification factor to decide that for the thin sample. The modification factor has been determined with MCNP to be 0.83+/-0.08 for a thickness of 1.2+/-0.2 mm. Using these values, 90Sr concentration has been estimated to be 0.11 Bq/g for the thin sample and 0.12 Bq/g for the thick sample, hence they are in good agreement.

Genetic polymorphisms in the cytochromes P-450 (1A1, 2E1), microsomal epoxide hydrolase and glutathione S-transferase M1, T1, and P1 genes, and their relationship with chronic bronchitis and relapsing pneumonia in children

The purpose of this study was to investigate the possible roles of the genes functioning in xenobiotic metabolism and antioxidant pathways in the development of severe chronic lung disease in children. Polymorphisms in the genes encoding CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1, and GSTP1 were investigated in cases of Tatar children with chronic bronchitis (n=129) and relapsing pneumonia (n=50) and in cases of ethnically matched healthy individuals (n=227) living in the city of Ufa, the Republic of Bashkortostan (South Ural region of Russia), by polymerase chain reaction-restriction fragment length polymorphism (PCR-RLFP) method. The frequency of the *2C allele of the CYP1A1 gene was significantly higher in patients than in the healthy control group (chi2=15.02, P=0.0007, Pcor=0.0021). This allele was associated with a higher risk of chronic bronchitis in children (OR 4.14, 95% CI 1.83-9.53; Pcor=0.0024). Similar results were obtained in cases of patients with relapsing pneumonia (OR 3.86, 95% CI 1.34-10.95; Pcor=0.027 for the *2C allele of the CYP1A1 gene). The frequency of the *5B allele of the CYP2E1 gene was higher in the relapsing pneumonia patients (7.0 vs 1.98% in the control group; chi2=5.68, P=0.018, Pcor=0.054; OR 3.72, 95% CI 1.21-11.24). The increase in the GSTT1 gene deletion was significant only in cases of chronic bronchitis (39.53 compared to 21.15% in the control group; chi2=12.96, P=0.001, Pcor=0.003; OR 2.44, 95% CI 1.48-4.04). Our results show that the presence of the GSTM1 gene deletion is unfavorable for the development of chronic lung disease in females (chi2=9.57; P=0.0029, Pcor=0.0116) and was associated with increased risk (OR 2.44, 95% CI 1.36-4.38). The distribution of EPHX1 and GSTP1 gene genotypes was similar in the control and patient groups. Our findings indicate that the polymorphisms of the CYP1A1, CYP2E1, and GSTT1 genes probably play a substantial part in susceptibility to severe airway and lung injury in cases of children with chronic bronchitis and relapsing pneumonia.

ESR Dosimetry of cow teeth from South Ural region

ESR Dosimetry of cow teeth from South Ural region

Biomonitoring of Heavy Metal Deposition in the South Ural Region: Some Preliminary Results Obtained by Nuclear and Related Techniques

The heavy metal pollution in the South Ural region was studied by nuclear and related techniques. The feasibility of the moss technique to study the regional air pollution is also presented.

Project RATEMA--one year's experience.

The RATEMA project is an international cooperation between the University of Ulm in Germany and the Urals Research Centre for Radiation Medicine in Chelyabinsk, Russia. For one year we conducted weekly conferences between the two sites, based on a satellite link with a 384 kbit/s connection. During the videoconferences the physicians on both sides--experts in radiation medicine--discussed the health status of Russian patients who had been chronically exposed to ionizing radiation in the South Urals region. The German partners presented patients with comparable haematological and oncological diseases. The project has shown the advantages and difficulties of working in an international and interdisciplinary environment. The experience gained has been very valuable for planning new projects with similar tasks. The results and the contents of the RATEMA database are the basis for education and research for physicians involved in the management of radiation victims.

Verification of occupational doses at the first nuclear plant in the former soviet union

Mean annual occupational exposures are reported for radiation workers at the first Russian industrial nuclear facility ‘Mayak’, South Ural region, for the period 1948–1988. The underlying individual doses originate from the register of the in-plant radiation safety department and are based on local film dosimetry results. Differentiation is made between personnel working at reactor and radiochemical processing plants. Verification of summed film doses is performed by means of ESR dose reconstruction using extracted teeth from selected individuals. Explanations are given for observed discrepancies between the reconstructed individual doses and original integrated film dosimetry results. The research potential of combined dose information from specific tooth enamel and dentine are shown.

Depth-dose distribution in bricks determined by thermoluminescence and by Monte-Carlo calculation for external γ-dose reconstruction

The analysis of depth-dose distributions in bricks sampled from walls in areas with nuclear waste or accident contamination has the potential of providing information on the energy and source configuration of the γ-radiation that had been incident on the brick. In this study, a brick from a mill facing a shallow water reservoir of the contaminated Techa river in the South Ural region is investigated. Thermoluminescence (TL) methods were used to measure the accumulated dose at several depths in the brick. The accidental external γ-dose is obtained by subtracting the natural radiation background dose from the total accumulated dose. In the first segment of the brick, at a depth of about 1.5 cm, the accident dose was found to be roughly 3.5 Gy. Monte-Carlo simulations of the photon transport from the reservoir bed contaminated with 137Cs were calculated for different depths in the brick. The calculations were made assuming different attenuating water levels. It is found that the depth-dose distribution determined by measurements corresponds to a water level between 20 and 50 cm. The results indicate that TL measurements combined with Monte-Carlo modelling calculations are highly promising for external γ-dose reconstruction applications.