In a number of oil producing regions of the world the production and treatment of oil is accompanied by NORM contamination of well equipment and technological facilities. Radioactivity of seales and oil sludges is caused by presence in them of radium isotopes in the form of radiobarite and products of their decay.
JSC "Tatneft" has developed a system of monitoring over the probable radiation impact on environment on the territory of its activity.
Oil sludges, deposited on oil treatment units, consist of heavy oil fractions and minerals, presented by oxides of silicon, iron, aluminium and a number of other compounds. Average content of radiobarite in oil sludges is 1–2%. Specific activity of radium isotopes achieves 18.5–29.6×104 Bq/kg.
Propagation of decay products of radium isotopes into environment is probable at the expense of radon release or formation of radioactive aerosols, their leaching from sites of temporary storage of oil sludges. Consequently, it is necessary to control the content of radioactive aerosols in atmospheric air and radium isotopes in surface and groundwaters.
Periodicity of determination of radionuclides content in different media depends on temperature variations by seasons, amount of falling precipitations, as well as by the conditions of temporary storage of oil sludges and their amount. The conducted measurements show that activity of radium isotopes in reservoirs or sources of groundwaters, located in the radius of 2–3 km from oil treatment facilities, does not exceed levels, established by sanitary regulations of Russian Federation (Ra-226 - 0.89 Bq/l, Ra-228 - 0.37 Bq/l). Comparison of these data with results of measurements conducted in the middle of 60-s shows that for the elapsed 30 years the average activity of radium isotopes in surface and groundwaters on the territory of JSC "Tatneft" did not change. The activity of aerosols in atmospheric air on the territory of production facilities for oil treatment and settlements also does not exceed safe levels.
The developed system of monitoring and observance of certain safety measures provide content of radium isotopes and products of its decay in the environment within limits, do not exceeding those established by environmental regulations.