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P u b l i s h e d M o n t h l y Si n c e 2 0 0 0 English translation of the monthly « Avtomaticheskaya Svarka» (Automatic Welding) j ournal published in Russian since 1948 ED I TOR I A L B OA R D Ed i t o r-i n-Ch i e f B. E. P a t o n Su b s c r i p t i o n s , issues per year, air postage and packaging included. B ack issues available.

Objective: to carry out the physiological and hygienic evaluation of the working conditions of operators producing chromium disilicide nanopowders by high-energetical mechanoactivation method and to develop the preventive recommendations. Material and methods. The object of research was the technological process of producing nanocrystalline chromium disilicide powder within a planetary ball mill. The hygienic assessment of the technological process, technological equipment and psycho-physiologic evaluation of the working environment of the operators were carried out using the generally accepted psychophysiological, hygienic, and chronometer methods of study. The concentration of nanoparticles in the working area was measured using the diffusion aerosol spectrometer DAS-2702 («Aeronanoteh», Russia), the nanopowder particle size was measured by the device Analysette 12 DynaSizer («Fritsch», Germany), the chemical composition of air samples was determined by atomic emission spectrometry with inductively coupled plasma (ICP-AES) using the device «Ortima 2100 DV» («Perkin-Elmer», USA). Results. It was found out for the first time that the mechanical activation process was accompanied by emission of nano-sized chromium into the air of the working area, which had not been detected before the beginning of the work. The total concentration of nanoparticles in the main room was 1.6-1.9 times higher than that in the working area of the planetary ball mill and exceeded the test levels recommended for nanomaterials in European countries. Conclusion. The basic adverse factors in case of producing nanopowder of chromium disilicide by mechanoactivation method are presence of nanoparticles of metals in the workplace air and intensity of work. We have proposed hygienic recommendations which are aimed at improving the plant design for the high-energy mechanical activation in the direction of ensuring tightness, reduction of manual work operations, audible and visual signaling during the technological process.