Predicting children's blood lead levels from exposure to school drinking water in Seattle, Washington, USA

Abstract

Objective: Lead exposure through drinking water is of increasing interest with little known about its potential childhood health impact. In 2004, school testing in Seattle, Washington, found lead concentrations in drinking water that exceeded national guidelines (>20 ppb). On the basis of these data, we estimated potential blood lead levels (BLLs) in elementary school children to better understand the potential health risks posed by these exposures.

Methods: We used the US Environmental Protection Agency Integrated Uptake Biokinetic Model for Lead in Children to predict geometric mean BLLs. We modeled typical-case and worst-case scenarios for children in 71 elementary schools on the basis of drinking water lead concentrations results from 2004.

Results: The estimated geometric mean BLLs under a typical scenario for each school ranged from 1.6 to 2.5 microg/dL. The worst-case scenario predicted geometric mean BLLs ranging from 1.7 to 5.0 microg/dL. All modeling yielded predicted BLLs well below the Centers for Disease Control and Prevention's public health goal of <10 microg/dL.

Conclusions: Our modeling suggests drinking water exposures up to 10-15 times the Environmental Protection Agency guideline are unlikely to result in BLLs exceeding the current guidelines of the Centers for Disease Control and Prevention in the absence of other significant exposure sources. In Seattle, elevated school drinking water lead concentrations are not a significant source of lead exposure in school-age children. Further characterization of drinking water impacts are merited only if younger-age children are consuming water or if water lead concentrations are higher than those in this study.