Category Archives: Emerging Testing Methods

A gift for mothers (and daughters, and all of us): New tools for breast cancer monitoring and prevention

Rachel Shaffer is a research assistant.

Our mothers are no doubt on our minds right now, after Mother’s Day weekend. And I am no exception, especially since, as I blogged about last year, this month is the anniversary of my own mother’s breast cancer diagnosis.

This year though, in addition to celebrating my mother’s recovery, I can find hope in a new report from researchers at the Silent Spring Institute that provides guidance to improve our ability to screen for and study potential breast carcinogens — thereby enhancing efforts to prevent this widespread disease. Good news, certainly… and a timely gift for all of the women in our lives.

This new report describes biomonitoring methods for 102 breast carcinogens with high exposure potential and identifies existing cohort studies into which these methods could be integrated immediately. These chemicals are among the 216 previously identified by the authors as chemicals linked to mammary gland tumors in rodents. By testing for exposure markers of these priority breast carcinogens in the population, researchers should be able to better identify and study high-risk groups, and regulators will be better able both to limit dangerous exposures and to demonstrate the public health benefits of these exposure reductions.

The full report is available online, but I want to highlight a few key themes that are particularly relevant to current scientific and political debates.  Read More »

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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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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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EDF launches website on EPA’s emerging chemical testing programs

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

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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Chemical safety evaluation: Limitations of emerging test methods

Jennifer McPartland, Ph.D., is a Health Scientist. Richard Denison, Ph.D., is a Senior Scientist.

Parts in this series:      Part 1     Part 2     Part 3     Part 4

This is the fourth in a series of blog posts on new approaches that federal agencies are exploring to improve how chemicals are evaluated for safety.  In this post, we’ll discuss a number of current limitations and challenges that must be overcome if the new approaches are to fulfill their promise of transforming the current chemical safety testing paradigm.  Read More »

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Chemical safety evaluation: Potential benefits of emerging test methods

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

Parts in this series:      Part 1     Part 2     Part 3     Part 4

This is the third in a series of blog posts on new approaches that federal agencies are exploring to improve how chemicals are evaluated for safety.  Previous posts primarily focused on the scientific principles underlying these efforts.  This post will take a pause from scientific fundamentals to discuss some of the opportunities presented by these more novel methods, while subsequent posts will address some of their limitations and remaining challenges.  (Not to worry, though, I’ll soon get back to computer-simulated organs as promised.)  Read More »

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Chemical safety evaluation: Packing tox tests into single drops of liquid!

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

Parts in this series:      Part 1     Part 2     Part 3     Part 4

In my last post I introduced EPA’s collaborative NexGen effort and briefly described the scientific advances underpinning the program.  In this post, I’ll explore some of the potential power of EPA’s efforts, which will require that we get a bit into the nitty gritty (nerd spoiler alert!).

NexGen is focusing on how new scientific knowledge and technological capabilities may interplay with traditional hazard and risk assessment that predominantly relies on more expensive and time-consuming animal studies.

There has been a lot of buzz around what is called high-throughput (HT) testing of chemicals.  Just last week, EPA issued a public statement describing the unveiling of a new robot housed at the National Institutes of Health Chemical Genomics Center (NCGC).  I highly recommend watching the robot in action by clicking on the “Toxicity Testing Robot System” video link available on the NIH National Human Genome Research Institute’s website.  The robot is scheduled to test 10,000 chemicals for potential toxicity!   So, what does that actually mean?  Read More »

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Chemical safety evaluation: EPA is doing the “Robot” 21st century style

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

Parts in this series:      Part 1     Part 2     Part 3     Part 4

Remember that then-new dance move from the 20th century?  Now don’t get too excited, EPA is not adding a dance category to its new sustainability research program.

No, the ‘Robot’ in my title refers to some of the impressive machines involved in EPA’s efforts to develop and apply new automated approaches to chemical toxicity testing.  These approaches integrate modern insights being gleaned from the biological sciences with advances in computation.  A new term has even been coined for all this:  Computational toxicology.

Though perhaps less of a draw than a dance-off featuring EPA staff, EPA’s exploration of new ways to better assess and address the safety of the tens of thousands of chemicals in use today is pretty exciting.    Read More »

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Testing for endocrine disruption: Are we there yet?

Cal Baier-AndersonCal Baier-Anderson, Ph.D., is a Health Scientist.

After long delays, the EPA’s Office of Pesticide Programs recently issued endocrine disruptor screening test orders for dozens of high-priority pesticide ingredients.  Endocrine disruptors are chemicals capable of interfering with the action of hormones that regulate biological processes such as development, growth, reproduction and metabolism.  The test orders require pesticide manufacturers to evaluate their chemicals using a specific battery of tests.

Identifying which chemicals are endocrine disruptors can help protect people and the environment from harmful exposures.  So, with test orders now in the hands of pesticide manufacturers, will we finally get the data we need? Read More »

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