[Selected biochemical indicators of the effect of environmental lead on the humans]

Lead after penetration into the human organism reacts with different sulphur compounds, especially with thiol group of peptides and proteins. It diminishes haeme synthesis by inhibiting thiol enzymes of bone marrow. Measurements performed in three groups of inhabitants of Chorzów--the most polluted town in the Upper Silesia, revealed in approx. 70% of workers of Nitrogen Chemical Plant (group A) and Steelworks (group S) a several-fold higher concentrations of blood lead, than in workers of Slaughterhouse (group M) in which it remained within the normal range for urban populations. In all subjects examined, the level of reduced glutathione in erythrocytes was approx. 50% lower in comparison to normal mean value. In urine, the highest excretion of delta-aminolevulinic acid (ALA), a precursor for haeme synthesis was found in group A, characterized by highest blood lead as well as in group M, with normal blood lead concentrations. The ALA excretion in group S was lower but it also exceeded the upper limit of normal range. Amounts of porphobilinogen excreted in urine exceeded the normal range, more frequently in group A and M than in group S, as in the case of ALA. These results indicate a widespread exposition of Chorzów inhabitants to lead, although the altered amounts of compounds studied show no correlation with the lead concentrations in blood. It seems that blood lead concentration may be modified depending on individual metabolic features, work conditions or diet.