Levels of trace elements in the serum and erythrocytes and some parameters of erythrocyte heme metabolism (FEP, ALA-D, ALA-U) in copper foundry workers.

The study was designed to investigate the usefulness of some biochemical indices for determination of lead toxicity. In exposed and control groups, the following parameters were measured: concentration of lead in the blood, level of free erythrocyte protoporphyrins and delta-aminolevulinic acid dehydratase activity of erythrocytes. Levels of sodium, potassium, calcium, magnesium, copper and zinc in the serum and erythrocytes as well as of iron in the serum were determined. The chelation test was performed and excretion of lead, coproporphyrins and delta-aminolevulinic acid (in 24 hour urine sample before and after EDTA injection) identified only in the exposed group. Absorption of lead was significantly higher in the exposed group (increased blood lead level (Pb-B), free erythrocyte protoporphyrin (FEP) and decreased erythrocyte ALA-dehydratase (ALA-D) activity. Levels of copper and calcium in the serum and red blood cells were significantly lower in comparison with the controls. Iron and sodium concentration in the serum as well as levels of potassium, magnesium and calcium in erythrocytes were significantly higher in the exposed group. The chelation test in the exposed group showed a significantly increased excretion of lead in 24 hour urine sample. Concentration of delta-aminolevulinic acid in 24 hour urine sample was lower after EDTA injection.