Impact of soil lead on children's urinary levels and parent-reported learning disabilities in areas of diffuse contamination.

Children's lead exposure has declined with the phasing out of leaded gasoline, while second order Pb sources, such as contaminated soils, have become more prevalent. Lead remains a pollutant of concern in contaminated urban and post-industrial areas, where legacy diffuse soil contamination levels are deemed acceptable with current soil management policies. However, the contribution of soil Pb, particularly its bioaccessible fraction, to children's internal Pb dose remains insufficiently characterized in these settings. This study investigates chronic Pb exposure in 172 children (6-11 years) living on soils with Pb levels of ∼ 400 mg/kg ("Liege area") and ∼ 50 mg/kg ("Control area"). It combines (i) human biomonitoring; (ii) oral bioaccessibility assessment (BARGE method); (iii) robust statistical modeling; (iv) coupled lifetime exposure-physiologically based toxicokinetic modeling (O'Flaherty 2000) and (v) exploratory investigation of parent-reported learning disabilities. Urine Pb concentrations ranged from 0.02 to 6.55 µg/L. Our results indicate that increasing soil Pb content (alongside old dwelling age and passive smoking) was associated with increasing urine Pb level in Liège but not in the control area. In Liège, where the reference value (RV95 = 1.8 µg/L) is exceeded for ∼ 10% of the children, higher urine Pb levels were observed alongside a higher frequency of parent-reported learning disabilities and lower parental education attainment. Although these exploratory findings should be interpreted cautiously, they highlight the convergence of social vulnerability and environmental degradation. Overall, our findings emphasize the persistent threat of legacy Pb contamination and call for integrated interdisciplinary strategies to protect children's health in contaminated urban environments.