[The efficacy of personal prevention measures in controlling the exposure to metals of welders].

Biological monitoring of welders employed in a power plant showed urinary nickel levels largely exceeding the reference values (Ni-U welders mean = 43.2, S.D. = 22.1 micrograms/24 h; Ni-U reference values mean = 2.7, S.D. = 1.4 micrograms/24 h). Subsequently urinary excretion levels of other metals (Cr, Zn, Fe, Mn, Cu, Al, Pb) were measured for a more complete assessment of occupational exposure of these subjects; only aluminum and lead were found to slightly exceed the reference values and correlate with urinary nickel levels. As a consequence of these results, some adjustments in personal prevention measures were introduced at the workplace; the subsequent biological monitoring checks showed a progressive reduction in urinary nickel excretion levels over time in all welders.