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

Abstract

Article history: Available online xxxx a b s t r a c tTo 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.

Source and pathway analysis of lead and polycyclic aromatic hydrocarbons in Lisbon urban soils

“…2A), and therefore of its bioavailability, in the surface environment. This result is in agreement with that of a previous study by Reis et al (2014a), which has indicated a correlation between the bioaccessibility of Pb and the relative proportion of carbonates in the soil samples. Furthermore, the correlation of Ca with a component (PC2) that is interpreted as anthropogenic suggests that Ca-phases of anthropogenic origin (e.g.…”

“…Samples were collected and processed as previously described in Cachada et al (2012Cachada et al ( , 2013 and Reis et al (2014a). In the laboratory, a representative amount of the <2 mm soil size fraction was ground to a fine powder in an agate mill and used to determine total concentrations of the contaminants and other physicochemical properties of the soil.…”

“…Whilst various studies available from literature indicate the ingestion of playground soil as key pathway of childhood exposure to Pb (De Miguel et al, 2007;Khan et al, 2016;Reis et al, 2014a), new lines of evidence suggest that for PAHs, such as benzo [a]pyrene (BaP), the three pathways may be of concern (Beriro et al, 2016;Wang et al, 2011;Yang et al, 2014).…”

“…precipitated with primary or secondary minerals, complexed by organic ligands) of the contaminant in the soil (Gleyzes et al, 2002;Reis et al, 2014a). A widely-used technique for understanding element distribution in the solid phase (known as fractionation) is based on the application of sequential selective chemical extractions (Denys et al, 2007;Patinha et al, 2015a;Reis et al, 2012).…”

“…Risk assessment studies encompassing the three pathways of exposure (ingestion, inhalation and dermal absorption) to PTEs and organic compounds carried out by the authors in the city of Lisbon have suggested that there is some health risk associated with the ingestion of Pb and PAHs in the urban soils (Cachada et al 2013;Reis et al 2014a). Thus, understanding factors that cause exposure of human population, and children in particular as the most vulnerable receptor, seemed of paramount importance.…”