Hair and Nail Lead Concentrations in Leather-Industry Workers Compared with Community Controls: A Cross-Sectional Study

Abstract

Occupational exposure to lead (Pb) remains a serious global public health concern, particularly in leather manufacturing, where workers are chronically exposed to toxic substances. Hair and nail matrices serve as reliable biomarkers for assessing long-term lead accumulation. Objective: To compare hair and nail lead concentrations between leather-industry workers and community controls in Sialkot, Pakistan. Methods: This analytical cross-sectional study was conducted on 80 adults, including 40 leather workers and 40 age- and sex-matched non-exposed controls. Hair and nail samples were collected, washed, decontaminated, and digested with nitric and hydrochloric acids before analysis with inductively coupled plasma–optical emission spectrometry (ICP-OES). Mean concentrations (µg/g) were compared using two-sided statistical significance testing, with p<0.05 considered significant. Results: Hair lead levels were significantly higher among workers than controls (0.3300 ± 0.6589 vs −0.0462 ± 0.0543 µg/g; p=0.0056). Similarly, nail lead concentrations were elevated in workers compared with controls (0.2662 ± 0.6521 vs −0.0240 ± 0.1002 µg/g; p=0.0067). The highest hair and nail lead concentrations were observed in workers aged 51–53 years (2.06 µg/g) and 55–60 years (2.91 µg/g), respectively. Lead concentrations showed a positive correlation with years of employment, indicating progressive bioaccumulation. Conclusion: Leather-industry workers exhibited significantly higher hair and nail lead concentrations compared with community controls, reflecting chronic occupational exposure. These findings emphasize the importance of routine biomonitoring, adequate protective measures, and enforcement of stricter occupational health and safety regulations in Pakistan's leather industry.