EDF Health

Selected tag(s): health-based benchmark

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

EDF’s assessment of a health-based benchmark for lead in drinking water

Tom Neltner, J.D.is Chemicals Policy Director

Health professionals periodically ask me how they should advise parents who ask about what constitutes a dangerous level of lead in drinking water. They want a number similar to the one developed by the Environmental Protection Agency (EPA) for lead in dust and soil (which is the primary source of elevated blood lead levels in young children). I usually remind them that EPA’s 15 parts per billion (ppb) Lead Action Level is based on the effectiveness of treating water to reduce corrosion and the leaching of lead from plumbing; it has no relation to health. Then I tell them that EPA is working on one and to hold tight. Admittedly, that is not very satisfying to someone who must answer a parent’s questions about the results of water tests today.

On January 12, EPA released a draft report for public comment and external peer review that provides scientific models that the agency may use to develop potential health-based benchmarks for lead in drinking water. In a blog last month, I explained the various approaches and options for benchmarks that ranged from 3 to 56 ppb. In another blog, I described how EPA’s analysis provides insight into the amounts of lead in food, water, air, dust and soil to which infants and toddlers may be exposed. In this blog, I provide our assessment of numbers that health professionals could use to answer a parent’s questions. Because the numbers are only a start, I also suggest how health professionals can use the health-based benchmarks to help parents take action when water tests exceed those levels.

EDF’s read on an appropriate health-based benchmark for individual action on lead in drinking water

When it comes to children’s brain development, EDF is cautious. So we drew from the agency’s estimates calculated by its model to result in a 1% increase in the probability of a child having a blood lead level (BLL) of 3.5 micrograms of lead per deciliter of blood (µg/dL).

EDF's assessment of a health-based benchmark for individual action on lead in drinking water
Age of child in home and type of exposureHouses built before 1950¹Houses built 1950 to 1978²Tests show no lead in dust or soil³
Formula-fed infant3.8 ppb8.2 ppb11.3 ppb
Other children 7 years or younger5.9 ppb12.9 ppb27.3 ppb

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Posted in Drinking Water, Emerging Science, Flint, lead / Also tagged , , , , | Comments are closed

With draft report, EPA takes major step to help communities assess risks from lead in drinking water

Tom Neltner, J.D.is Chemicals Policy Director

Communities around the country are testing their water for lead. But when they get the results, parents, public health officials, housing agencies and school officials have little guidance about what the number means and what actions to take or priorities to set. For lead in dust and soil in homes, child-care and schools, they have health-based numbers that serve as benchmarks for assessing risk. There is no such benchmark for drinking water. As a result, many are using the “Lead Action Level” of 15 parts per billion (ppb) as a surrogate. Yet, this level is based on the effectiveness of corrosion control; it has no relation to the associated health risks of lead exposure.

Yesterday, the Environmental Protection Agency (EPA) helped fill the void by releasing a draft report that provides three different approaches to setting a scientifically-robust “health-based benchmark” for lead in drinking water. The agency is seeking public comment on the draft and will convene a panel of scientific experts to consider each of the approaches.

The report is a critical step in implementing the recommendations of the agency’s National Drinking Water Advisory Council (NDWAC) which called for this type of health-based benchmark as part of an overhaul of the Lead and Copper Rule. The agency went a step further and provides alternatives to consider. We applaud EPA for its action and its rigorous, scientific analysis.

Accounting for the various models and assumptions, EPA developed a range of potential health-based benchmarks that range from 3 to 56 ppb of lead in water that people actually drink. However, you cannot readily compare these values to the typical water testing results reported by utilities or schools. Those tests are based on the first draw of water that has been sitting in the faucet and plumbing overnight and do not necessarily reflect what people drink over the course of a day. Later samples would likely be lower but could be higher if the building has a lead service line, especially if the line has been disturbed. Read More »

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