Abstrakt: |
The paper presents a review of current state of the issue of studying the mechanism of welding aerosol (WA) formation, dispersity of welding aerosol solid component and its ability to penetrate into the human body, as an important toxicological factor. It is established that there exist two main mechanisms of WA formation -- due to condensation of high-temperature evaporation products and due to formation of volatile oxides on molten metal surface. Here, the molten metal drop is the main evaporation source, but weld pool and metal spatter also participate in the evaporation process. It is known that penetrability depends, chiefly, on dimensions of particles and their agglomerates: the smaller their size, the higher the penetrability. In addition to the already known paths of WA particle penetration into the body through the respiratory tract and digestive organs, nanosized particles can penetrate directly into the brain through nerve endings in the sinuses, as well as penetrate into the blood-vascular and lymphatic systems. This results in their accumulation in the bone marrow, lymph nodes, spleen and heart. Issue of searching for the methods to lower the emissions in coated-electrode welding is still urgent, chiefly due to improvement of their coating composition, as well as the ability to control particle dispersity in WA. 25 Ref., 1 Figure. [ABSTRACT FROM AUTHOR] |