Monthly Archives: January 2013

21st Century on the horizon for endocrine disruptor screening?

Rachel Shaffer is a research assistant. Jennifer McPartland, Ph.D., is a Health Scientist.

BPA, DDT, PCBs, PBDEs, phthalates, PFOA … Forgive the alphabet soup, but chances are you’ve heard of at least some of these endocrine-disrupting chemicals (EDCs), which have been the subject of a lot of public and media attention in the last several years. Research has begun to uncover the ways in which these chemicals can interact with the body’s hormone – or endocrine – system to disrupt various natural biological processes, including metabolism, the reproductive system, and development of the brain and nervous systems.

While the endocrine-disrupting properties of the chemicals named above have been confirmed, scientists suspect there may be many more such chemicals in our environment, in the products we use, and in our bodies.  How can we identify them?

Legislation enacted in 1996 required the U.S. Environmental Protection Agency (EPA) to develop a screening program to identify potential EDCs.  More than 10 years later, EPA finally launched the Endocrine Disruptor Screening Program (EDSP).  Testing is being conducted in two phases, or “tiers.”  In “Tier 1,” a screening battery of validated in vivo and in vitro assays is used to identify chemicals with potential to interfere with the endocrine system. Chemicals flagged in the first tier of testing are then subject to “Tier 2” testing intended to determine the specific effect and the lowest dose at which it occurs. (We should note this program is very controversial and the subject of ongoing debate, but that is not the subject of this post.)

EPA has identified an estimated 9,700 chemicals to be screened – a very daunting task given the time- and resource-intensive nature of the testing battery EPA has established.  Might there be a way to expedite the identification and testing of the more problematic chemicals? A study published earlier this year in Environmental Health Perspectives (EHP) investigates a possible approach: using in vitro high-throughput (HT) assays developed through EPA’s ToxCast and Tox21 programs to target and prioritize chemicals for further testing under the EDSP. While use of these assays poses its own challenges, might it at least help in determining an appropriate testing sequence?  Read More »

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ECHA raises its sights: Several recent additions to the REACH Candidate List set precedents

Alissa Sasso is a Chemicals Policy Fellow.

The European Union is maintaining a steady pace as it works to address chemicals of concern: Last month, the European Chemicals Agency (ECHA) added 54 Substances of Very High Concern (SVHCs) to the Candidate List for Authorisation under its REACH Regulation, bringing the total number of substances on the list to 138. ECHA posted a press release listing the new SVHCs and describing some of the more interesting additions, which we’ve highlighted below.

For 23 of the additions, REACH’s Member State Committee (MSC) reviewed public comments during the comment period on draft SVHC proposals before voting unanimously to add all of them onto the Candidate List. The other 31 new additions were not challenged during the public comment period, and hence moved directly onto the candidate list without MSC consultation.

The majority of the new SVHCs, like most substances already on the list, are classified as carcinogen, mutagenic and/or toxic to reproduction (CMRs).  But it’s with the other new listings that it gets really interesting.  Read More »

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States act while Congress fiddles

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

Lest anyone thought that efforts by state legislators to protect their citizens from toxic chemical exposures would slacken despite Congress’ inability to take such action, this week’s announcement that legislators in at least 26 states are introducing such bills should dispel that notion.

Safer States, a national coalition of state-based environmental health organizations, notes that “between 2003 and 2011, 19 states adopted 93 chemical safety policies. The majority of legislation passed with healthy bipartisan support – 99% of Democratic legislators and 75% of Republican legislators voted in favor of bills, and both Republican and Democratic governors signed them into law.”

That trend shows no signs of abating in 2013, based on a list of state legislative activities underway, compiled by Safer States (more detail here):  At least 26 states are each to consider multiple legislation and policy changes this year that will:

  • restrict or label the use of bisphenol A (BPA) in receipts, children’s products and food packaging;
  • require removal of certain toxic flame retardants from children’s products, home furniture or building materials;
  • change disclosure rules so that concerned consumers will have a way to identify toxic chemicals in products;
  • encourage manufacturers to remove identified toxic chemicals in favor of safer alternatives.
  • ban cadmium, a dangerous, persistent metal that is often found in inexpensive children’s jewelry;
  • ban formaldehyde from cosmetics and children’s products; and
  • promote green cleaning products in schools.

The chemical industry frequently argues it just can’t live with a “patchwork” of requirements that vary from state to state.  But that’s just what it’s creating by dragging its feet on reform of the federal Toxic Substances Control Act (TSCA), which has never been amended since its adoption nearly four decades ago. 

State legislators, like nature, abhor a vacuum.

 

 

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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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Variety is the spice of … accurate chemical testing

Rachel Shaffer is a research assistant.  Jennifer McPartland, Ph.D., is a Health Scientist.

There has been a lot of buzz in recent years about the federal government’s new chemical testing initiatives, ToxCast and Tox21 (see, for example, these articles in Scientific American and the New York Times).  These programs are developing high-throughput (HT) in-vitro testing to evaluate—and ultimately predict—the biological effects of chemicals.  In contrast to the relatively slow pace of traditional animal testing, ToxCast and Tox21 use sophisticated robots to rapidly test thousands of chemicals at a time. As a result, they hold the potential to more efficiently fill enormous gaps in available health data, predict adverse effects, and shed light on exactly how chemicals interact and interfere with our biology. (For more on these potential benefits, see Section 5 of EDF’s Chemical Testing Primer).

Yet, among the key challenges that these new methods must address is one that traditional, animal-based methods have faced for decades: how can laboratory testing adequately account for the high degree of variability in the human population? The latest research suggests the exciting possibility that genetic diversity, at least, may be able to be incorporated into emerging HT in vitro approaches.   Read More »

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