High blood lead levels are associated with lead concentrations in households and day care centers attended by Brazilian preschool children.

BACKGROUND: A previous study observed high blood lead levels (BLL) in preschool children attending 50 day care centers (DCC) in São Paulo, Brazil. OBJECTIVE: To identify whether lead levels found in both homes and DCC environments are associated with high blood lead levels. METHODS: Children attending 4 DCCs, quoted here as NR, VA, PS and PF, were divided into two groups according to BLL: high exposure (HE: ≥13.9 µg/dL; 97.5 percentile of the 2013 year sample) and low exposure (LE: <5 µg/dL). For in situ lead measurements (lead paint mode: mg/cm2 and ROHS mode: µg/g) in the children's households and in the DCC environments, a field portable X-ray-fluorescence analyzer was used. Multiple logistic regressions were performed to control for confounding factors. Odds ratios were adjusted for age, sex, day care center's measured lead, and tobacco. RESULTS: In an NR DCC building, 33.8% of the measurements had lead levels >600 µg/g, whereas such levels were observed in 77.1% of NR playground measurements. In VA DCC, 22% and 23% of the measurements in the building and in the playgrounds had levels higher than 600 µg/g, respectively. The percentage of high lead levels in the children's houses of the LE group was 5.9% (95% CI: 4.3-7.6%) and 13.2 (95% CI: 8.3-18.0%) in the HE group. Moreover, a significant association was found between high BLLs and lead levels found both in households and DCCs (p < 0.001). Most of the high lead measurements were found in tiles and playground equipment. CONCLUSIONS: Lead exposure estimated from the DCCs, where children spend about 10 h/day, can be as relevant as their household exposure. Therefore, public authorities should render efforts to provide a rigorous surveillance for lead-free painting supplies and for all objects offered to children.

Can in vivo surface dental enamelmicrobiopsies be used to measure remote lead exposure?

Measuring lead in the surface dental enamel (SDE) using biopsies is a rapid, safe, and painless procedure. The dental enamel lead levels (DELLs) decrease from the outermost superficial layer to the inner layer of dental enamel, which becomes crucial for the biopsy depth (BD) measurement. However, whether the origin of lead found in SDE is fully endogenous is not yet established. There is also controversy about the biopsy protocol. The aims of this study were to investigate if DELLs are altered by extrinsic contamination (A) and to evaluate the real geometric figure formed by the erosion provoked by biopsy procedure and the respective BD in SDE (B). To accomplish the aim A, lead from 90 bovine incisor crowns lead was determined by graphite furnace atomic absorption spectrometer as a function of exposure time and lead concentration. Two biopsies were performed in each tooth, before and after lead exposure. Six 15-tooth groups differed by exposure time (1 or 30 min) and lead concentrations (A. 0 mg/L-placebo, B. 0.01 mg/L-standard for drinking water, or C. 0.06 mg/L-concentration found in contaminated groundwater). Phosphorus was determined by an inductively coupled plasm optical emission spectrometer to quantify the enamel removed. To compare intakes/losses of lead in SDE among the groups, values of DELL differences between before and after lead exposure were compared by ANOVA (p < 0.05). To attain the objective B, one extracted human permanent tooth was studied by confocal Raman microscopy. Lead measurements and the surface profile were determined. There was no difference in DELL among the groups (p = 0.964). The biopsy bottom surface area, analyzed by microscopy, showed an irregular area, with regions of peaks and valleys, where areas with depth ranging from 0.2 (peaks) to 1.8 µm (valleys) (± 0.1 µm) could be found. BD carried out in vivo is commonly calculated using the cylinder height formula. The real BD was shown to be very similar to already published data. In conclusion, the SDE of erupted teeth does not seem to be susceptible to environmental lead intake, being thus reliable to measure remote exposures to lead.