RESEARCH – December 2004

Additional modalities to assess the long-term toxic effect of occupational hazards


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At the present time, it is not possible to draw reliable evidence with respect to presence or absence of damage of metabolism related to the long-term effects of occupational hazards. The aim of this study was to present data indicating that occupational air pollutants have the ability to induce long-term damages of heme synthesis. The effects of long-term exposures to organic solvents, welding fumes or diesel exhaust on porphyrins and heme synthesis in blood cells were investigated. Altogether 21 participants exposed to these air hazards were examined at the Centre of Occupational Diseases and Labour Medicine and were asked to complete a questionnaire. All patients were matched for age and gender with the control group.

The levels of 5-aminolevulinic acid (ALA), porphobilinogen (PBG) and protoporphyrin (PP), activities of ALA synthetase (ALA-S), ALA-dehydratase (ALA-D) and ferrochelatase (FC) were investigated in lymphocytes and erythrocytes spectrophotometrically. The content of metals, related to heme synthesis or metabolism, were measured in the blood plasma by flame atomic absorption spectrometry method.

Long-term exposure to organic solvents, welding fumes or diesel exhaust caused alterations in heme synthesis and in metal content in the human organism. Our data showed that chronic exposure to organic solvents caused accumulation of ALA and reduction of FC in lymphocytes. Chronic exposure to welding fumes leads to a significant accumulation of ALA in lymphocytes and erythrocytes. Long-term exposure to diesel exhaust causes a moderate accumulation of ALA and a significant decrease in FC activity in blood cells.

Our findingsprovideevidencethatlong-termexposure to air pollution is an important factor in development of chronic diseases.