[Value of the studies of multimodal evoked potentials for evaluation of neurotoxic effects of combined exposure to lead, copper and zinc].

Central nervous system dysfunction was studied in workers with occupational exposure to Pb+Cu+Zn by measuring somatosensory evoked potentials of short and long latency, visual evoked potentials and brain-stem evoked auditory potentials. The tests were done in 40 workers with a history of exposure from 6 to 19 (mean 14.3) years in a copper foundry. Pb poisoning was not diagnosed in them, but 18 workers had some abnormalities of heme synthesis. Pb concentration in blood was from 11.4 to 62.8 (mean 35.7) mcg% in the whole group. Pb concentration in air in the foundry exceeded 1.1-175 times the MAC value, the concentration of CU exceeded it 7.25 times. Zn concentration was half the MAC value. No significant abnormalities were found in the parameters of multimodal evoked potentials. The obtained data suggest a protective effect of copper and zinc on heme , Pb blood level and conduction velocity of somatosensory, visual and auditory impulses in workers exposed to high Pb air concentration.