Urban Green Spaces and Newborns Metal Concentrations in Rio de Janeiro, Brazil

Background: Brazil is the largest country in South and Latin America with an accelerated urbanization process, and the city of Rio de Janeiro is the second most populous. The PIPA Cohort Project is the first prospective study investigating the effects of urban exposure to multiple pollutants on maternal–child health in Brazil. Objective: This paper describes the relationship between maternal socio-environmental conditions and newborns’ umbilical cord blood concentrations of metals (lead, arsenic, and mercury). Methods: The study population was a convenience sample of all babies born at the UFRJ Maternity Hospital over a period of 12 months from pregnant women aged 16 or older living in Rio de Janeiro. Demographic, socio-economic, lifestyle, work, and housing variables were collected. Metals concentrations were analyzed in umbilical cord blood using the inductively coupled plasma mass spectrometry technique. Results: There were 844 (93%) eligible births, with 778 (94%) cord blood samples collected. The detection rate of Pb, Hg, and As were 99% (742), 94.5% (708), and 61% (450), respectively. The total green area percentage (PAGT) of urban residence zones was one primary socio-environmental characteristic determinant of high metal exposure (≥median). Newborns living in city zones with lower total green area percentages (PAGT) had equal to or above-median cord blood concentrations of at least one metal (p = 0.026), of lead and mercury (PbHg) at the same time (p = 0.006), or of lead (p = 0.006). The city zones with the worst indicators of greenspace availability also presented human development indexes (HDI) under the city’s mean HDI. Conclusion: The study provides evidence that the lower availability of urban green spaces in residential zones is associated with greater environmental exposure to pollutants (metals) during pregnancy and can constitute a socio-environmental vulnerability indicator.