Platinum levels in nasal lavage fluid as a biomarker for traffic-related exposure and inflammation in children

Platinum (Pt) is a well-known constituent of particles emitted by catalytic converters during car operation. To evaluate Pt as a potential marker for traffic related particle exposure, we investigated Pt content along with metals vanadium (V) and chromium (Cr) in coarse and fine particulate matter (PM), sampled in four areas with different traffic density, as well as in the nasal lavage (NAL) of 67 children (average age: 6 years) living in these areas. The different sites were characterised by significant differences in air pollutants including PM, NO, NO2, CO and Cr, but differences in V or Pt were absent. No significant differences in neutrophil and epithelial cell counts or concentrations of the neutrophil chemoattractant interleukin- 8 (IL-8) were found in the NAL of children living in the different areas. In addition, the concentrations of V, Cr and Pt, which were detectable in 64%, 73% and 93% of the individuals, respectively, did not differ between the different locations. However, in the NAL of the children, a significant correlation between Pt and the number of neutrophils/ml (r = 0.40, p < 0.001) as well as of epithelial cells/ml (r = 0.41, p < 0.001) was found. No relation was present between nasal inflammation and nasal Cr levels, whereas a relatively weak association was observed between V and epithelial cells counts (r = 0.30, p = 0.018). In conclusion, our data suggests a role for nasal lavage Pt as a candidate biomarker for traffic-related PM, which is able to induce inflammation in the upper respiratory tract.