[Materials for adjusting MAC of lead in the workplace air]

The authors present materials of clinical and hygienic study checking MAC for lead in the air of workplace. The study covered 506 workers of printing, nonferrous metallurgy plants and storage battery production. The study included examination of cardiovascular, nervous, digestive systems and laboratory values and revealed high diagnostic value of serum lead level and low one of urinary lead level. High number of the groups examined and mathematical processing of incomplete selects (Caplan--Meyer assess) proved that intoxication resulted from higher lead concentrations (0.58-0.8 mg/m3). The lead levels of 0.2 mg/m3 in 23.7% of cases induced changes of 2-3 laboratory values-first signs of lead intoxication--and in 5.2% of cases some symptoms of vegetative sensory polyneuropathy were seen. These lead levels are therefore determined as minimally acting. Calculations of probability parameters for health risk helped to set MAC for lead in the air of workplace at 0.05 mg/m3 (this value is accepted by Russian Health Ministry) with mandatory control of serum lead level.