Impact of occupational safety and health services on urinary heavy-metal burden and respiratory function in construction workers

Objectives. This study aimed to evaluate the impact of occupational safety and health (OSH) services on reducing the urinary heavy-metal burden and preserving respiratory health in construction workers. Methods. A cross-sectional study (n = 60) compared construction workers receiving OSH services (n = 30) with an unprotected cohort (n = 30). Respiratory function was assessed via spirometry. Spot urine samples were analyzed for an 11-element heavy-metal panel using inductively coupled plasma mass spectrometry (ICP-MS). Results. Unprotected workers exhibited significantly higher urinary concentrations for 10 of 11 analyzed metals (including aluminum, zinc, copper, chromium and manganese; p < 0.05), excluding cadmium. A substantial proportion of the non-OSH cohort approached or exceeded threshold limit values (TLVs). Correlation analyses in the non-OSH group also indicated strong multi-metal co-exposure patterns, suggesting shared occupational sources or overlapping exposure pathways. Within the unprotected group, individuals with abnormal spirometry demonstrated significantly higher cumulative heavy-metal burdens compared to those with normal pulmonary function. Conclusion. Comprehensive OSH services significantly mitigate systemic heavy-metal accumulation and protect respiratory health. These biological findings strongly support policy interventions to expand mandatory OSH coverage to self-employed and informal construction workers, alongside targeted biomonitoring to prevent toxic occupational exposures.