Blood lead, mercury and cadmium concentrations in 1- to 4-year-old children attending day care centers in Sao Paulo, Brazil – preliminary results

INTRODUCTION: In Brazil, there are scarce data on metals contamination, especially for the more vulnerable population composed by preschool children. Information on the prevalence of the exposure to metals is essential to formulate public health policies. The aim of this cross-sectional study was to estimate the blood lead (Pb), cadmium (Cd) and mercury (Hg) levels in children attending Day Care Centers (DCCs) in São Paulo, Brazil. METHODS: This study included 50 DCCs, totalizing 2,463 children aged 1-4 years. Venous blood samples were analyzed by inductively coupled plasma mass spectrometry with quadrupole (q-ICP-MS) and dynamic reaction cell (DRC-ICP-MS). Prior to analysis by ICP-MS, 200 µL of each blood sample was diluted 1:50 into a 15-mL polypropylene Falcon® tube with a solution containing 0.01% (v/v) Triton® X-100, 0.5% (v/v) nitric acid and 10 μg L−1 of Rh as the internal standard. Descriptive statistics was used. RESULTS: We present here the preliminary results of 354 children attending 9 DCCs. Geometric means for blood Pb, Cd and Hg levels were: 15.70 µg/L (95% CI: 14.95 - 16.54 µg/L); 0.30 µg/L (95% CI: 0.28 - 0.33 µg/L) and 0.76 µg/L (95% CI: 0.68 - 0.84 µg/L), respectively. CONCLUSIONS: These preliminary results showed that, considering the Fourth National Report on Human Exposure to Environmental Chemicals by CDC (2013), in Brazilian children, the blood Pb concentrations are very similar to those found in the U.S. children, but the blood levels are higher for Cd and Hg. However, it should be emphasized that these data included only a subsample of the whole study and it is necessary to wait for the results of the whole epidemiological study to know if the Brazilian children are at risk of these metals poisoning.

This study was approved by Ethical Committee (CEP-USP, №128.943) and funded by FAPESP (Grants 2011/13076-0, 2011/23272-0 and 2012/21840-4).