Objective: This study assesses 2,5-hexanedione (2,5-HD) in the urine of subjects exposed to n-hexane solvent between 1991 and 1998, from details obtained from the Registry of Biological Monitoring (BM) at the Florence Local Health Unit, and its development over time.
Methods: The Registry contains 15,925 samples from 6,650 subjects occupationally exposed to n-hexane, especially in leather (9,099 samples; 3,607 subjects) and shoe (3,865 samples; 1,938 subjects) production.
Results: Over the time span studied there was a total reduction of 31.9% in urinary 2,5-HD level. The yearly decrease over the entire period was 5.4%. Dividing the 8 years into three periods: before the introduction of the new legislation for health protection in the workplace (1991-1993), during its transition (1994-1996) and after its complete enforcement (1997-1998), respectively, we observed a marked decrease in the last period. Women and young people (under 30 years) experienced significantly higher absorption levels (respectively, 7.1% and 24.4%).
Conclusion: The data suggest that monitoring was more frequent in subjects with higher starting values, and the greatest decrease was reported in this group. Reduction may be due to less n-hexane in the products used, better structural conditions in the factories, and the effectiveness of inspections carried out by the authority for hygiene and safety in the workplace. The results confirm the usefulness of the reporting of risk levels of exposure to industrial toxicants by routine biological monitoring.