High Blood Lead Levels in Brazilian Preschool Children: Investigation of Exposure Sources

Abstract

Background/Aim: Lead is known as one of the most dangerous environmental pollutants. In 2013, a previous study showed high blood lead levels (BLL) in preschool children attending Day Care Centers (DCC), in São Paulo, Brazil. The objective of this study was to analyze the main sources of lead exposure, considering the home and school environments, previously studied by questionnaires. Methods: This cross-sectional study included 4 DCC (NR, PS, PF, VA), which presented 1-4-year-old children with higher BLLs among the 50 DCC participants in 2013. Children (n=54) were sorted out into "high exposure" (≥ 13.9µg/dL – 97.5 percentile of the 2013 sample) and "low exposure" (<5µg/dL). The X-ray fluorescence portable analyzer was used for the lead direct analysis in the environment. Screenings were performed to evaluate the lead concentrations in DCC’s building and playgrounds and children’s households, including wall paints, toys, floors, doors, windows, tableware items, among others. Results: There was found a significant difference in the BLL>5μg/dL percentage among the DCCs. The highest BLL percentage was found in the “NR” DCC (69.6%), and the lower was found in the “PS” DCC (20%). In “NR” DCC building, 28.2% of the measurements were positive (>600 ppm), while 72.2% were positive in playground. Positive measurements in “PS” DCC building were 32% and 50% in playgrounds. A significant association was found between high BLL and lead found in households and DCC (p<0.001). Most of the positives measurements were found on tiles, painted iron window structures, doors and playground equipment. Conclusions: The results showed that the lead exposure estimated from the DCCs, where children spend about 10 hours/day can be as relevant as their household exposure. Therefore, public authorities should render efforts to provide a rigorous surveillance for lead–free supplies painting and all objects offered to children.