Urban geochemistry of lead in gardens, playgrounds and schoolyards of Lisbon, Portugal: Assessing exposure and risk to human health

• We aim assessing exposure and health risk posed by Pb in urban soils and dusts.
• We aim assessing influences of site-specific bioavailability data in risk assessment.
• Exposure is estimated for each site.
• Exposure estimates are adjusted with site-specific bioavailability data.
• Estimated hazard quotients are more elevated for dusts.

To assess the impact of potentially harmful elements in soil/dust on the health of children that use urban recreational areas to play outdoors, an urban survey of Lisbon, the largest city in Portugal was carried out, collecting soils and dusts from public gardens, parks, playgrounds and schoolyards. An exposure and risk assessment study for the incidental soil/dust ingestion of lead was carried out based on US EPA guidelines using a sub-set of 19 topsoil and 8 outdoor dusts, out of a total of 51 samples, incorporating oral bioaccessibility measurements using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives are: (i) interpretation of soil and dust oral bioaccessibility measurements; (ii) assessment of site-specific exposure and non-carcinogenic risk posed by lead; (iii) hazard assessment for urban soil and dust with respect to children playing in outdoor recreational areas. The results show that significant fractions of Pb occur in bioaccessible forms, 24–100% in soils and 35–100% in dusts and the associated risk is greater for dust ingestion than for soil ingestion in Lisbon city recreational areas.