Children's Exposure to Lead from Tap Water in Child Care Centers and Estimation of Blood Lead Levels

The continuous exposure of young children to low levels of lead is a public health concern since it is associated with adverse neurodevelopmental effects. Drinking water is a potentially important source of lead exposure for children. In the present study, lead concentrations from a public dataset that contains 27,734 regulatory water samples collected in child care centers across Ontario, Canada were analyzed to determine the water lead concentration distributions for each public health unit. The seasonal changes of the water lead concentrations were also assessed. Children's blood lead levels (BLLs) were estimated using the Integrated Exposure Uptake Biokinetic model for children aged 1-5 years old. In this analysis, the median lead concentrations of the flushed samples were used to estimate the average exposure, and the 90th percentile of the standing samples was used to estimate the worst-case scenario. The results indicated that the geometric means of the modeled BLLs varied from 1.5 to 1.6 (GSD = 1.6) mu g/dL for the average (median) exposure scenario which is significantly lower than the 5 mu g/dL level of concern for children. However, the geometric means of the modeled BLLs varied from 3.9 to 4.9 (GSD = 1.6) mu g/dL for the worst-case (90th percentile) scenario which indicate relatively elevated blood lead levels for children.