Urinary Biomarkers of Exposure and Effect in California Schoolchildren From a High Air Pollution Area

Exposure to air pollution is associated with adverse health effects such as asthma, lung cancer, and cardiovascular diseases. Children are especially vulnerable due to their developing organs, immature immune systems, and higher ventilation rates relative to their body size. Although the adverse health effects of air pollution are well established, the contribution of specific pollutant constituents and the biological mechanisms underlying these effects are not fully understood. This pilot study investigates biomarkers of oxidative stress and inflammation and their association with urinary biomarkers of air pollutant exposure in children. Eighteen children were recruited from an elementary school in Stockton, CA and provided a total of 67 urine samples. Biomarkers of oxidative stress and inflammation were measured using enzyme-linked immunosorbent assays. Liquid chromatography with tandem mass spectrometry was used to measure urinary metabolites of six VOCs and four PAHs. Biomarkers of oxidative stress and inflammation were positively correlated with urinary metabolites of acrylonitrile, acrolein, crotonaldehyde, naphthalene, and fluorene. Two-fold increases in crotonaldehyde and naphthalene metabolite levels were significantly associated with 8-Isop, 8-OHdG and PGE2, with percent-changes ranging from 13%-21% and 11%-16%, respectively. A two-fold increase in crotonaldehyde metabolite level was also significantly associated with a 41% change in CC16. These results suggest that urinary biomarkers of oxidative stress and inflammation may serve as useful tools for assessing chemical exposures and early biological effects in children.