EDF Health

Selected tag(s): In vitro

EDF comments at EPA workshop on applying systematic review methodology to IRIS assessments

By Rachel Shaffer / Published: August 27, 2013

Rachel Shaffer is a research assistant.

Lately, much of the attention of the environmental health community has been focused on Capitol Hill and the Lautenberg-Vitter chemical safety reform bill that would amend the antiquated Toxic Substances Control Act (TSCA). Yet significant – if somewhat esoteric – developments are underway at EPA that will also have major impacts on how the safety of chemicals is assessed.  EPA has been implementing improvements to its Integrated Risk Information System, commonly known as “IRIS.” The purpose of the IRIS program is to evaluate information on the effects of potential exposures to environmental substances and provide health hazard assessments, which are then used to support regulatory decisions across the agency.  And while it isn’t directly affected by TSCA or its reform, IRIS provides both indirect and direct support to the office at EPA that does administer TSCA.  

In other words, what happens in IRIS doesn’t stay in IRIS.

So… what’s IRIS up to? Read More »

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21st Century on the horizon for endocrine disruptor screening?

By Rachel Shaffer / Published: January 31, 2013

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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Variety is the spice of … accurate chemical testing

By Rachel Shaffer / Published: January 10, 2013

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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EDF launches website on EPA’s emerging chemical testing programs

By Jennifer McPartland / Published: November 12, 2012

Jennifer McPartland, Ph.D., is a Health Scientist.

New approaches for evaluating chemical hazard and risk are needed to help address substantial data gaps that exist for the thousands of chemicals currently in the marketplace as well as those yet to be introduced.   EPA has been investing significant resources to create research programs dedicated to advancing new types of chemical testing and assessment approaches.  But what exactly are these approaches?  How might they improve the practice of risk assessment?  Are they appropriate for decision-making, and if so, what kinds of decision making?  What role does the public interest community have to play? 

To explore these and other important issues, EDF’s Health Program has launched a website, “Chemical Testing in the 21st Century,” that provides an  introduction to these new approaches and the programs the EPA has built around them—including their potential uses, benefits and limitations.  The website includes the following informational resources: 

  1. Chemical Testing in the 21st Century: A Primer – An introduction to EPA’s Computational Toxicology (CompTox) research initiative and its component programs, such as ToxCast; a discussion of the opportunities and challenges of these new testing programs; and a discussion of issues and needs for greater engagement by the public interest community.  
  2. Chemical Testing in the 21st Century: Webinar Series – Linked audio and video recordings of each of EDF’s three webinars (held in October) featuring EDF and EPA scientists exploring the basics of EPA’s new testing programs and the promises and challenges they present. 

We will soon be adding a page with descriptions of and links to additional resources.

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Exposing our ignorance: EPA study reveals barren exposure data landscape

By Jennifer McPartland / Published: March 16, 2012

Jennifer McPartland, Ph.D., is a Health Scientist.

This past November, EPA scientists published a sobering paper, “The exposure data landscape for manufactured chemicals,” in the journal Science of the Total Environment.  The paper reveals how little systematic information we have about human and environmental exposures to the thousands of chemicals in use today.

The aim of the study was “to define important aspects of the [chemical] exposure space and to catalog the available exposure information for chemicals being considered for analysis as part of the U.S. EPA ToxCast screening and prioritization program.”  Its conclusion:  “The results suggest that currently available exposure data are insufficient to provide the evidence base required to inform risk assessment and public health decision making.”  Not good, but not surprising.  Read on for more detail. Read More »

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A new power couple: The combined impact of the microbiome and chemical exposures on disease susceptibility (Part 1 of 2)

By Allison Tracy / Published: December 15, 2011

Allison Tracy is a Chemicals Policy Fellow.  EDF Health Scientist Dr. Jennifer McPartland and Senior Scientist Dr. Richard Denison contributed to this post.

When you’re standing at the kitchen counter this holiday season wrestling with the nebulous world of weight gain, think about synthetic chemicals.  A good number of them are in you.  And studies show that some of them are pretty busy in there, interacting with various biological systems – including your metabolism.

But they’re not the only show in town.  Microbes are busy in your gut doing important things like digesting food and degrading harmful compounds.  But could they also influence the size of your love handles?  New science suggests that these microbes—in concert with certain chemicals—may have just this effect.

It is becoming increasingly clear that it’s not just your genes and your self control that determine your risk for obesity and related complications like diabetes.  Environmental factors are a big part of the equation, and those factors just might extend to synthetic chemicals to which you’re exposed, such as the flame retardants in your furniture and the plasticizers in food can linings.  Read More »

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