Category Archives: Emerging Science

Missing the forest for the trees? Are we addressing the biggest risks from exposure to phthalates?

Lindsay McCormick is a Research AnalystRichard Denison, Ph.D., is a Lead Senior Scientist

A recent study published in Environmental Health Perspectives is the first to demonstrate a link between childhood asthma and prenatal exposure to certain phthalates.  Phthalates are a group of chemical plasticizers used in hundreds of everyday products, including home construction materials, toys, food packaging, medical devices, and synthetic fragrances found in personal care products, cleaning products, cosmetics, and air fresheners.  For the most part, it is impossible for the average consumer to know what products are made with phthalates; however, if you see the word “fragrance” listed on your shampoo or sun screen, it may well contain a phthalate.  

Several studies have suggested that phthalate exposure may have an adverse impact on children’s respiratory health (for example, see here, here, and here).   However, none of these studies has considered the potential role of prenatal exposure – exposures to the fetus in the womb – to phthalates.

The prenatal period is a critical developmental window for lung and respiratory health.  Thus, researchers at the Columbia Center for Children’s Environmental Health (CCCEH) hypothesized that prenatal phthalate exposure would be associated with later development of asthma in childhood.  To investigate this hypothesis, the researchers measured phthalate metabolite levels in the urine of 300 women in the 3rd trimester of pregnancy, and then followed the children of these women to assess the extent to which they developed asthma between the ages of 5 and 11.  Read More »

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Is BPA a carcinogen?

Sarah Vogel, Ph.D., is Director of EDF's Health Program.

Add liver cancer—a childhood cancer on the rise in the US—to the growing list of potential health effects associated with bisphenol A (BPA) exposure that are under scrutiny by researchers.  A recent study by scientists at the University of Michigan, published in Environmental Health Perspectives, is the first ever to report a dose-dependent, statistically significant relationship between perinatal (before and just after birth) exposures to environmentally relevant levels of BPA and development of cancerous liver tumors later in life.

There are three particularly notable features of this study: first, the dose levels used; second, the timing of when those doses were delivered; and third, the age at which effects were observed.  Read More »

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Unnerving developments in the state of the evidence on developmental neurotoxicity

Rachel Shaffer is a research assistant.

Seven years ago, leading children’s environmental health experts Philippe Grandjean and Philip Landrigan published a groundbreaking review that identified five chemicals prevalent in the environment—lead, methylmercury, polychlorinated biphenyls (PCBs), arsenic, and toluene—as developmental neurotoxicants. In their follow-up review released last week, they have added six more chemicals—manganese, fluoride, polybrominated diphenyl ethers (PBDEs), chlorpyrifos, DDT, and tetrachloroethylene (PERC)—to this list. The implications of early-life exposures to these common compounds, say the authors?  A “global silent pandemic of neurodevelopmental toxicity.”  Read More »

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It’s a generational thing: Evidence grows that environmentally induced epigenetic changes can be passed down from one generation to the next

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

We’ve blogged here before about the growing evidence that environmental exposures can cause changes in gene expression – not to be confused with mutations, which are changes in the DNA itself.  We’ve noted that these changes in how and when our genes are turned on and off may actually be heritable, along with any biological or behavioral changes they induce.  That is, not only might the individual who is directly exposed suffer effects, but – and here’s the kicker – so might descendants who never experienced the original exposure.

Now, several new studies add even more evidence that epigenetic changes may be transgenerational.  In the past 10 days, the Washington Post has run articles detailing three new studies in mice, each of which strongly indicate that dietary deficiencies and environmental exposures can reprogram DNA in ways that can be passed along to reside in the DNA of the offspring of the affected individuals.  Read More »

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April brings showers…and a flurry of new studies on the risks of perfluorinated chemicals

Rachel Shaffer is a research assistant.

What do waterproof jackets, car wax, and non-stick pans have in common?

Aside from being great Father’s Day presents (Dad, I’m thinking ahead this year!), they also all are made with perfluorinated compounds, or PFCs. There are hundreds of different PFCs, and their oil- and water-resistant properties make them useful in a variety of products, from cookware and carpets to food-packaging and electronics.  

Unfortunately, these chemicals have less desirable properties as well. Thanks to their strong molecular bonds, PFCs do not readily break down; they persist in the environment and in our bodies. And, widespread use has led to extensive human exposure. The Centers for Disease Control’s (CDC) human biomonitoring program, the National Health and Nutrition Examination Survey (NHANES), detected four types of PFCs in over 98% of samples representative of the U.S. population collected in 2003-2004.  

Two of the compounds detected in NHANES, perfluorooctane sulfonic acid (PFOS) and perfluorootanoic acid (PFOA), are the focus of three new studies published this month in Environmental Health Perspectives. These studies, one reporting an association with osteoarthritis in women, another an association with semen quality in men, and a third an association with asthma in children, add to a growing concern about the potential adverse effects of these ubiquitous chemicals.

What follows is a brief overview of the findings of these new studies.  Read More »

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Regrettable, if predictable: Bisphenol S mimics estrogen just like its better-studied cousin, bisphenol A

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

A rule of thumb in chemistry is that chemicals that look alike will more often than not act alike.  (If it looks like a duck … .)  Indeed, when chemical companies are faced with testing requirements for one of their chemicals, they routinely argue that they should be allowed to submit test data on a structurally related chemical instead. 

So when it was revealed that companies making products (such as thermal receipt paper) that contain the estrogen-mimicking compound bisphenol A (BPA) were switching to another chemical called bisphenol S (BPS), many scientists’ eyebrows quickly arched.  Read More »

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No way to treat our kids: Formaldehyde, flame retardants and other toxics exceed safe levels in air and dust in day care centers

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

A study conducted by the State of California [Update 10-26-12:  The study was funded by the California Air Resources Board and conducted by Asa Bradman and colleagues at the Center for Environmental Research and Children’s Health at UC Berkeley] – described as “the first comprehensive study in child care centers to measure a broad spectrum of pollutants including many volatile organic chemicals, particles, and pesticides, and emerging pollutants such as flame retardants, phthalates and perfluorinated compounds” – has routinely detected dozens of these toxic contaminants in the air or floor dust present in such facilities. 

Some of the key findings include the following:

  • “Formaldehyde levels in 87% of the facilities exceeded the California acute and chronic reference exposure guideline levels for non-cancer health effects such as respiratory and sensory irritation (e.g. eyes, nose, throat, and lungs).”
  • “In most facilities, levels of formaldehyde, acetaldehyde, chloroform, benzene, or ethylbenzene exceeded child-specific Safe Harbor Levels computed by the report authors based on Proposition 65 guidelines for carcinogens.”  [These are levels calculated to result in a cancer risk of at least 1 per 100,000 people.]
  • “Phthalates, flame retardants, pesticides, perfluorinated compounds, and lead were also frequently detected in dust and/or air.”
  • “Child dose estimates from ingestion of dust for two brominated flame retardants (BDE-47 and -99) exceeded the non-cancer U.S. EPA reference health dose (RfD) in 10.3% of facilities for children < 1 year old.”
  • “Two VOCs commonly found in cleaners and personal care products, d-limonene and decamethylcyclopentasiloxane, had the highest concentrations compared to other chemical groups.”

The presumed sources of most if not all of these chemicals are everyday materials and products used to construct, furnish or clean these facilities.  Formaldehyde, for example, is used in hundreds of materials and products, including furniture, wood products, carpeting, paints, and household cleaning products.  California took action in 2007 to limit is use in pressed wood products, and Congress passed a law in 2010 to do the same.  (Unfortunately, the proposed regulations needed to implement the federal law – which Congress mandated be in place by January 1, 2013 – are stuck in regulatory review limbo at the Office of Management and Budget (OMB):  The proposed regulations were sent by EPA to OMB’s Office of Information and Regulatory Affairs (OIRA) more than 170 days ago, on May 5 of this year, but remain under “pending review” by OIRA despite the requirement for OIRA to complete its reviews within 90 days.)

The larger problem exposed by the California study demands, of course, a far more comprehensive solution – TSCA reform.

 

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The Sweet Smell of … Cardiovascular Hazards?

Kyle Ward is an intern in EDF's Health Program.  Jennifer McPartland, Ph.D., is a Health Scientist.

When you think of air fresheners what is the first thing that comes to mind?  Fresh spring flowers?  French vanilla?  Reduced Heart Rate Variability?  While that last one may not be on everyone’s mind, it certainly has been for one team of scientists.  They have recently conducted the first study ever to examine the potential for exposure to household cleaning sprays, air fresheners and scented products to adversely affect people’s cardiovascular systems.  Their findings, published in last month’s Environmental Health Perspectives, show a linkage between long-term use of household sprays and scented products and reduced heart rate variability (HRV).  Reduced HRV is associated with increased risk for a host of negative health effects ranging from heart attack to death.   Read More »

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Exposure to toxic flame retardants is an environmental justice issue: New research finds differential exposure in children

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

A peer-reviewed paper released today documents that nonwhite toddlers in North Carolina carry nearly twice as much of certain toxic flame retardant chemicals in their blood compared with white toddlers.  The finding adds to a growing body of evidence that exposures to toxic chemicals are higher in communities of lower socioeconomic status.

Numerous other studies have found higher levels of the flame retardants known as polybrominated diphenyl ethers, or PBDEs, in children and adolescents relative to adults.  The current study – authored by Stapleton et al., and appearing in Environmental Health Perspectives – may be the first, however, to demonstrate differential exposure based on socioeconomic status. Read More »

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Linking everyday chemicals to disease: New science keeps on intensifying the writing on the wall

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

As a Washington policy geek, it’s sometimes hard not to let the ups and downs of political prospects for achieving real improvements in public health protections from toxic chemicals get me down.  The tenacity with which some stakeholders insist on throwing wrenches into the works to block efforts to reach middle ground is indeed depressing.

But through it all, there is one constant that continually restores my optimism that we’ll eventually get where we need to get to:  Science keeps moving forward and inexorably points toward the need for reform.  I will use this post to briefly highlight four recent studies that demonstrate the changing landscape of our knowledge of how environmental factors, including toxic chemical exposures, are affecting our health.  What’s noteworthy about these studies is that they all identified adverse health effects in human populations, and linked those effects to early-life exposures.  They all also illustrate the complex interplay between chemical exposures and social or other environmental factors that directly challenges the overly simplistic and non-scientific approach to causation that our chemicals policies have taken for decades.

Below are summaries of and links to these new studies:

  • Early-life exposure to PCE is associated with later-life risky behaviors.
  • Phthalate exposure is associated with excess weight in New York City children.
  • Exposure to perfluorinated chemicals may interfere with childhood vaccine effectiveness.
  • Epigenetic changes are associated with socio-economic status and biomarkers for cardiovascular disease.

Read More »

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