Hair biomonitoring reveals spatial heterogeneity of multielement exposure in Bogotá schoolchildren

Children in large Latin American cities may experience concurrent exposure to multiple environmental metals. This study quantified hair concentrations of lead (Pb), manganese (Mn), cadmium (Cd), mercury (Hg), and copper (Cu) in Bogotá schoolchildren to assess spatial heterogeneity across four administrative localities.Query In a cross-sectional design, 69 pooled scalp-hair samples from 14 public schools were washed, digested, and analyzed using atomic absorption spectrometry (flame, graphite furnace, and cold vapor, as applicable). Key quality control steps included blanks, certified-reference materials, matrix-spike recoveries, and instrument triplicates; batches not meeting precision criteria were reanalyzed or flagged (see Supplementary Tables S2-S9). Missing data were handled via multiple imputations. Inter-locality differences were assessed with Kruskal-Wallis tests, and multielement patterns compared using PERMANOVA. Statistically significant differences were found for Pb, Mn, and Cd (p < 0.05), with higher levels in Bosa and, to a lesser extent, Usaquén. Hg levels were low and spatially uniform. These findings support the use of school-based hair biomonitoring to detect spatially structured metal exposure and guide targeted environmental-health actions in urban settings.