Effect of air quality on oxidative stress and elemental levels in hair and urine of Italian and Chilean students

In this study, urinary oxidative stress biomarkers and the concentrations of 41 elements were measured in the hair and urine of students from two universities: one in Rome and one in Santiago, Chile. In addition to biological samples, PM10 samples were collected to analyze their elemental content and oxidative potential (OP; measured using cell-free DCFH, AA, and DTT assays). All elements were analyzed using ICP-MS and HG-AFS (1,2), while oxidative stress biomarkers were determined by HPLC/MS-MS. The final concentration of the analytes was expressed in μg/g of creatinine to normalize values with respect to urine dilution variability (3). During data processing, the influence of variables related to the participating students, such as age, sex, body mass index, smoking, and diet, was evaluated. The average PM10 concentration was 26 μg m-3 in Rome and 71 μg m-3 in Santiago, Chile, indicating significantly different inhalation exposure levels in the two areas. Specifically, levels of Cu, Mo, Sn, and Sb—tracers of noncombustive vehicular traffic (mechanical abrasion of brakes; 4,5)—were significantly higher in Chilean PM10 samples compared to Italian ones. The OP values measured by the DCFH and AA assays were also notably higher at the Chilean site, confirming a significant contribution of non-combustive vehicle traffic to the oxidative potential of the dust. The different elemental concentrations in PM10 resulted in different metal and metalloid accumulation levels in the two biological matrices studied. The elements that showed the most significant differences between Italian and Chilean students in both biological matrices were Cs, Hg, Mg, Mo, Rb, Sr, Tl, and Zn. In contrast, Al and Sn varied significantly in urine and hair, not based on geographic area but depending on the participant's gender. Oxidative stress biomarkers showed higher values in the urine of smokers, while no significant differences were found between Italian and Chilean urine samples.