Abstract
Seventy male factory workers were studied. The lead concentrations in their blood (Pb-B) were 16.55±11.53 μg/100 ml (range 1.5 to 50.2 μg/100 ml). The subjects were divided into three groups according to Pb-B (in μg/100 ml): group A, Pb-B ≤10 (n=22); group B, 10<Pb-B ≤20 (n=30); group C, Pb-B >20 (n= 18). The mean±S.D. in each group was 5.57±2.53, 15.02±2.75, and 32.52±9.49 μg/100 ml, respectively. Pb in plasma was 0.011±0.010, 0.017±0.033, and 0.021±0.021 μg/liter, and Pb in the RBC was 0.281±0.246, 0.701±0.325, and 1.626±0.861 μg/g Hb, respectively. In addition to Pb concentration, the concentrations of 34 elements in the plasma or in the RBC were determined. Se concentrations in RBC in each group were 0.618±0.139, 0.670±0.207, and 0.728±0.200 μg/g Hb, and the mean values were significantly different between groups A and C (p<0.05). For Se concentrations in plasma, the mean±S.D. in each group was 0.132±0.035, 0.130±0.031, and 0.126±0.021 μ g/ml, respectively, and there was no significant difference between groups. On the other hand, when the activities of total SOD, Mn-SOD, Cu, Zn-SOD, and catalase in the plasma and the activities of GSR-Px both in the plasma and in the RBC were assayed, some differences were found. The activities in GSH-Px in RBC were 17.19±5.03, 17.59±3.95, and 15.25±3.18 μmol/g Hb/min, and those in plasma were 0.069±0.032, 0.081±0.023, and 0.080±0.028 μmol/ml/min. In group C, GSR-Px activity was lower in the RBC and higher in the plasma than those in group A, and it was observed that the Se concentration was higher in RBC, and that there was no remarkable change in the plasma. Catalase activity in group C was 3.58±0.81 mgH2O2/ml/30 min, which was significantly higher than that in group A (2.81±0.90 mg H2O2/ml/30 min). Further investigation is necessary in order to explain the above results. The regular indices used for evaluating lead exposure, showed significant correlations with Pb-B: r=−0.786 vs δ-Aminolevulinic acid (ALA) dehydratase activity in blood, r=0.927 vs. inhibition rate, and r=0.339 vs. ALA in urine.
