Biological chromium and nickel monitoring in metalworkers: welders versus non-welders

BACKGROUND: Welding fumes contain toxic metals, such as chromium (Cr) and nickel (Ni), which pose long-term health risks, including chronic respiratory diseases and cancer. Tungsten inert gas (TIG) welding of stainless steel generates ultrafine particles of these metals. Evidence on urinary concentrations in welders is limited. AIMS: To assess urinary Cr and Ni concentrations in male metalworkers, according to job role and smoking habits and evaluate associations with exceeding ACGIH biological limit values (Cr: 0.7 μg/l; Ni: 5 μg/l). METHODS: In this cross-sectional study, 245 male metalworkers from Friuli Venezia Giulia were recruited, including 179 welders and 66 non-welders. Demographics and smoking history (pack-years) were collected during annual health surveillance. End-of-week urine samples were analysed for Cr and Ni using inductively coupled plasma mass spectrometry. Group differences were tested with non-parametric methods. Logistic regression estimated adjusted odds of exceeding biological limits. RESULTS: Welders had higher median urinary Cr and Ni than non-welders (0.75 versus 0.56 μg/l; P = 0.020 and 1.70 versus 1.10 μg/l; P = 0.0001, respectively. Half of the subjects (50.0%) exceeded the Cr limit. Welding was associated with a borderline higher odds of exceeding the Cr limit (OR = 1.71; 95% CI 0.96-3.06; P = 0.070). Age and smoking were not related to exceeding limits. CONCLUSIONS: Welders are exposed to higher urinary Cr and Ni levels than non-welders, with stronger associations for Cr. Findings support the need for preventive intervention and targeted biomonitoring, particularly in TIG stainless steel welding.