Hematological effects of chronic heavy metal exposure in children from marginalized occupational communities in...

Children engaged in precarious labor activities may experience exposure to environmental contaminants, including heavy metals, particularly in marginalized communities. Limited evidence exists regarding the potential hematological implications of such exposures in pediatric populations. A cross-sectional study was conducted among 50 children (<18 years) from three communities in San Luis Potosí, Mexico, engaged in informal recycling (Zone B), artisanal brickmaking (Zone C), or artisanal stone-carving (Zone A). Urinary concentrations of 15 metals were determined by ICP-MS, and hematological parameters were assessed using an automated analyzer. Associations were examined using nonparametric statistics, age-adjusted correlations, Bayesian Kendall's Tau analysis, and post hoc power evaluation. Distinct urinary metal profiles and hematological parameters were observed across the study zones. Zone B showed higher concentrations of Cr, Co, Ni, Al, and Sn, whereas As was elevated in Zone C. Hematological differences included higher WBC, lymphocyte, granulocyte counts, and MPV in Zone C. Age-adjusted correlations identified associations of As with WBC, lymphocyte, and granulocyte counts; Co with platelet indices; and negative correlations of Ni, Al, and Sn with several hematological variables. Bayesian analysis confirmed robust associations for Co with WBC, Al with granulocytes, and Sn with MPV. This study provides exploratory evidence of associations between urinary metal concentrations and hematological parameters in children engaged in precarious labor activities. While preliminary, the findings underscore the importance of child-focused public health strategies and support the need for larger, longitudinal studies to validate these associations and clarify their implications.