Selected category: Health Science

Children’s lead exposure: Relative contributions of various sources

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

Last week, we noted in our blog that the Environmental Protection Agency (EPA) dropped the statement that paint, dust and soil are the most common sources of lead in its “Protect Your Family from Lead in Your Home” booklet. Property owners provide this booklet to prospective homebuyers and tenants in housing built before 1978. The change implicitly recognizes that there is no safe level of lead in the children’s blood, and we must reduce all sources of lead exposure. It also acknowledges that the relative contribution of air, water, food, soil, dust, and paint to children’s blood lead levels is complicated. Exposure varies significantly based on age of the home, the child’s race and age, the family’s income-level, and region of the country. Any simplification obscures these important differences.

EPA’s scientists made this clear in a model published earlier this year that pulled together the available data, divided children into three age categories, and assigned children in each category into ten groups based on their overall lead exposure. For each group, they estimated the relative contribution of air, water, food, and soil/dust (from paint). Not surprisingly, children living in older homes with lead-based paint hazards by far have the most exposure to lead. For 1 to 6 year olds in the top 90-100 percentile, more than 70% of the lead in their blood is from soil and dust. The contribution from food is 20% and drinking water is 10%. For infants, soil and dust contributes to 50% of the lead in blood, while 40% is from water and 10% from food.

Since there is no known safe level of lead in blood, we must do even more to reduce children's exposure to lead-contaminated soil and dust.

However, to prioritize action at a national level, it is important to understand how different sources contribute to lead exposure in the average child as well as the most-exposed child. We used the underlying EPA data to calculate the average relative source contribution of different sources to blood lead levels for infants from birth to six months old, for toddlers 1 to 2 years old, and young children from 1 to 6 years old. The results indicate that infants have a much higher source contribution of lead from water in comparison to older children (Figure 1). For the average child 1 to 6 years old, food is the largest source of lead exposure, with 50%, followed by soil/dust then water.

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Also posted in Drinking Water, Emerging Science, EPA, Health Policy, lead, Public Health| Tagged , , , , , , | 1 Response

EDF comments at EPA’s public meeting on identifying chemicals for prioritization stress legal requirements and urge adoption of sound and fair policies

Richard Denison, Ph.D.is a Lead Senior Scientist.

EPA held a public meeting today on “Approaches to Identifying Potential Candidate Chemicals for Prioritization” under last year’s reforms made to the Toxic Substances Control Act (TSCA) by the Lautenberg Act.

EPA provided brief opportunities for stakeholders to provide comments.  Four of us from EDF gave oral comments at the meeting.  Below we provide links to those comments in written form and briefly describe them (in the order in which they were presented).

EDF Senior Attorney Robert Stockman’s comments argue that, under the law, EPA:

  • must use its broad information-gathering authorities under section 4, 8 and 11 of TSCA to collect all “reasonably available information” to inform the prioritization process;
  • should exercise those authorities in the processes leading up to and including prioritization; and
  • should start immediately to develop additional information on chemicals in its Work Plan.

EDF Project Manager Lindsay McCormick’s comments:

  • stress the need to use its information-gathering authorities to develop experimental data early in the prioritization process;
  • caution against over-reliance on voluntary information submissions;
  • urge EPA to avoid implanting a bias toward information-rich chemicals; and
  • remind EPA of its obligations to make full health and safety studies and underlying data publicly available.

My comments:

  • stress that the law sets a higher bar for low-priority than for high-priority designations;
  • urge EPA to identify only small numbers of low-priority candidates at a time;
  • caution EPA not to identify categories of chemicals as candidates for low-priority designations; and
  • argue EPA should consider ensuring a minimum set of hazard data is available for candidates.

EDF Senior Scientist Dr. Jennifer McPartland’s comments point to serious limitations and critical caveats relating to some of EPA’s proposed approaches for identifying candidates, including:

  • Canadian Categorization and Chemicals Management Plan;
  • Safer Choice Ingredient List; and
  • Functional category approaches.
Also posted in EPA, Health Policy, TSCA Reform| Tagged , | Leave a comment

Senate funding proposal to eliminate EPA’s IRIS program is a public health debacle

Jennifer McPartland, Ph.D., is a Senior Scientist with the Health Program.

Among other things, IRIS chemical reviews are used to inform clean-up decisions at Superfund and other contaminated sites, set standards to ensure clean drinking water, assess health risks from toxic air emissions, and evaluate health risks of chemicals in commerce. These are all legally mandated activities stipulated under different laws to ensure the water we drink, the air we breathe, and the lands where we work, live, and play are safe.

Yesterday, the Senate Committee on Appropriations majority posted their version of the FY2018 Interior, Environment and Related Agencies appropriations bill online (see bill here and accompanying explanatory statement here; see the minority’s summary response here). The legislation lays out spending measures for a number of agencies including the Environmental Protection Agency (EPA).  In releasing the bill yesterday, the majority has bypassed the amendment and markup process.

Among other cuts, the bill eliminates the EPA Integrated Risk Information System (IRIS) Program. At best a small fraction of its responsibilities – and only one-third of its funding – would be re-allocated to the Office of Chemical Safety and Pollution Prevention (OCSPP).

If realized, this short-sighted move would be a debacle in terms of protecting public health from harmful chemical exposures.

[A short fact sheet on IRIS and implications of eliminating it is available here.]

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Also posted in EPA, Health Policy, Industry Influence| Comments are closed

EPA’s latest analysis shows perchlorate risks to fetal brain development

Tom Neltner, J.D.is Chemicals Policy Director and Maricel Maffini, Ph.D., Consultant

Pursuant to a consent decree with the Natural Resources Defense Council (NRDC), the Environmental Protection Agency (EPA) is developing drinking water regulations to protect fetuses and young children from perchlorate, a toxic chemical that inhibits the thyroid’s ability to make the hormone T4 essential to brain development. The rulemaking is part of a long process that began in 2011 when the agency made a formal determination that Safe Drinking Water Act standards for perchlorate were needed. Under the consent decree, EPA should propose a standard by October 2018.

In the latest step in that process, EPA’s scientists released a draft report in September that, at long last, answers questions posed by its Science Advisory Board in 2013: does perchlorate exposure during the first trimester reduce production of T4 in pregnant women with low iodine consumption? Does reduction in maternal T4 levels in these women adversely affect fetal brain development? According to EPA’s scientists, the answers are Yes and Yes.

For several years, EPA and the Food and Drug Administration (FDA) have developed and refined a model that would predict the effect of different doses of perchlorate on levels of T4 in pregnant women. The latest version of the model addresses women during the first trimester, especially those with low iodine intake. This is important because iodine is essential to make T4 (the number four indicates the number of iodine atoms present in the hormone); perchlorate inhibits its transport from the blood into the thyroid. The risk of perchlorate exposure to fetuses in the first trimester is greatest because brain development starts very early and is fully dependent on maternal T4. If the mother gets insufficient iodine to offset the perchlorate inhibition, she will not produce enough T4 for the fetal brain to develop properly. When free T4 (fT4) levels are low but without increase in thyroid stimulating hormone (TSH), the condition is known as hypothyroxinemia. When T4 production is lowered further, the pituitary gland releases TSH to increase T4 production by a feedback loop mechanism.

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Also posted in Drinking Water, Emerging Science, EPA, FDA, Food, Health Policy, perchlorate, Public Health, Regulation| Tagged , , , , , , , , , , , | Comments are closed

EPA proposes limits on hypochlorite bleach to reduce degradation to perchlorate

Tom Neltner, J.D.is Chemicals Policy Director and Maricel Maffini, Ph.D., Consultant

Every 15 years, the Environmental Protection Agency’s (EPA) Office of Pesticide Programs (OPP) reviews the safety of registered pesticides. The current cycle ends in 2022. As part of that process, the agency is evaluating the safety of hypochlorite bleaches. In January 2017, EPA decided it would consider the risks posed by degradation of the hypochlorite into perchlorate.

This is important for two reasons: 1) degraded bleach is less effective as a pesticide, and 2) perchlorate is a chemical that interferes with the production of thyroid hormone, a critical hormone for fetal and infant brain development.

On September 22, EPA proposed changes to the pesticide label to minimize the degradation for hypochlorite bleach used to disinfect drinking water, and the agency is accepting comments until November 21, 2017. The label would advise users to:

  • Minimize storage time;
  • Maintain pH of the solution between 11 to 13;
  • Minimize exposure to sunlight;
  • Store at lower temperatures; and
  • If practical, dilute with cool softened water upon delivery.

EDF submitted comments to EPA supporting EPA’s proposal and requesting specific changes to the proposed language, including making the advice to users mandatory. We also asked the agency to extend the label requirements to hypochlorite bleach used to treat produce and to disinfect food handling equipment. Bleach appears to be one of several significant sources of perchlorate contamination of food. Improving management conditions will reduce degradation and preserve effectiveness regardless of the whether the bleach is used in drinking water or to treat vegetables.

EPA’s proposal is an interim decision. We also were pleased to see that OPP is committed to continue working with EPA’s Office of Water (OW) in its assessment of the risks of perchlorate to pregnant women and young children. We asked OPP to incorporate the OW’s findings in additional interim registration decisions for all uses of hypochlorite bleaches.

 

Also posted in EPA, Health Policy, perchlorate, Public Health, Regulation| Tagged , , , | Comments are closed

“Tore apart our happy home”: Another chemical embraced by Dourson and Beck is contaminating the drinking water supply in Memphis and across the country

Richard Denison, Ph.D.is a Lead Senior Scientist.

[Use this link to see all of our posts on Dourson.]

That lyric from a Chuck Berry signature song, “Memphis, Tennessee,” takes on a haunting new meaning in light of the latest evidence of contamination of the Memphis Sand aquifer, a main drinking water source for the city, with the highly toxic solvent tetrachloroethylene (also known as perchloroethylene (PCE), or more commonly PERC).  Lest there be any doubt about the human toll this is taking, read this local woman’s heart-wrenching story.

The source of PERC in this case is a former dry cleaning business that is now a hazardous waste site, and because of Sharri Schmidt’s case is now nominated to become a Superfund site.  The chemical is still widely used in dry cleaning as well as in many other uses.  It’s a probable human carcinogen, and is also toxic to the brain, kidney and liver.

As I write, Dourson and Beck are making decisions that will help determine how the risks of PERC and other chemicals are assessed and whether or not they need to be regulated.

Unfortunately, Schmidt is far from alone.  PERC contamination of drinking water is widespread in this country.  To name just a few, have a look at these stories from towns and cities in North Carolina, Indiana, Nevada, Arizona, Montana, and New York.

Data compiled by the Environmental Working Group from local water utilities shows that PERC was detected in tap water samples taken by water utilities in 44 states that serve 19 million people.

One might hope and think that affected local communities could turn to the US Environmental Protection Agency for help in such situations.  The sad truth is that under the Trump administration this may well not be the case.  Trump has nominated Michael Dourson to lead EPA’s chemical safety office, who, despite the fact that he’s yet to be confirmed, is already working at EPA as a special advisor to Administrator Scott Pruitt.  And Pruitt has already installed as a political appointee to that office Nancy Beck, who until May was a senior official at the American Chemistry Council (ACC), the chemical industry’s main trade association.

So what do Dourson and Beck have to do with PERC?   Read More »

Also posted in Health Policy, Industry Influence, TSCA Reform| Tagged | Read 1 Response
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