ESTIMATION OF INDIVIDUAL DUST EXPOSURE BY MAGNETOPNEUMOGRAPHY IN STAINLESS-STEEL PRODUCTION

The objectives of the study were to measure the magnetic dust lung bur den of workers in stainless steel production by magnetopneumography (M PG) and to investigate the relationship of the results with air-borne concentrations of dust, total and hexavalent chromium as well as urina ry excretion of chromium. There were 128 workers from the chromite min e, sintering plant, ferrochrome smelter, stainless steel smelting shop , cold rolling mill and welding shop in the exposed groups and five pe rsons from the office staff in the control group. The remanent magneti c field (RMF) in the lungs was slightly elevated among workers in the ferrochromium and steel smelting shops; the levels were, however, lowe r than those reported for welders earlier and those observed in the we lding/repair shop. Workers in the mine, concentrator and sintering pla nts and in the cord rolling mill exhibited remanent magnetic fields co mparable to the referents. There was a relationship between the RMF an d the actual urinary chromium concentration. Miners and concentrator a nd sintering plant workers showed retarded relaxation rate (ReR) of th e remanent magnetic field. However, the RMF of the first two of these groups were low (< 0.1 nT) and this made it difficult to measure the R eR accurately. The duration of exposure correlated weakly but signific antly with the relaxation rate, while smoking was not related to it. ( C) 1997 Elsevier Science B.V.