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New EPA model enables comparison of various sources of childhood exposure to lead

Tom Neltner, J.D.is Chemicals Policy Director and Dr. Ananya Roy is Health Scientist

This week, Environmental Health Perspectives published an important article by scientists at the Environmental Protection Agency (EPA) that sheds important light on the various sources of children’s lead exposure. Led by Valerie Zaltarian, the article shares an innovative multimedia model to quantify and compare relative contributions of lead from air, soil/dust, water and food to children’s blood lead level. The model couples existing SHEDS and IEUBK models to predict blood lead levels using information on concentrations of lead in different sources, intake and gut absorption. The predicted blood lead levels compared well with observed levels in the National Health and Nutrition Evaluation Survey population. Given the variety of independent sources of lead exposure, the model provides a critical tool that public health professionals can use to set priorities and evaluate the impact of various potential standards for all children and not just those with the greatest exposure.

This peer-reviewed article builds on a draft report EPA released in January 2017 evaluating different approaches to setting a health-based benchmark for lead in drinking water. The report has provided a wealth of insight into a complicated topic. Earlier this year, we used it to show that formula-fed infants get most of their lead exposure from water and toddlers from food, while the main source of lead for the highest exposed children is soil and dust. In our February blog, we provided our assessment of a health-based benchmark for lead in drinking water and explained how public health professionals could use it to evaluate homes. The information was also critical to identifying lead in food as an overlooked, but meaningful, source of children’s exposure to lead.

The new article reaffirms the analysis in the January 2017 EPA report and highlights that evaluating source contribution to blood lead in isolation versus aggregating across all sources can lead to very different answers and priorities. A health-based benchmark for lead in drinking water could vary from 0 to 46 ppb depending on age and whether all other sources of lead are considered. For example, a health-based benchmark for infants (birth to six months old) would be 4 ppb or 13 ppb depending on whether or not you consider all sources of exposure.

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Posted in Drinking Water, Emerging Science, EPA, Food, Health Policy, lead, Uncategorized / Also tagged , , , , , , , | Comments are closed