EDF Health

Selected tag(s): In vivo

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

By / 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 / 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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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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Avoiding paralysis by analysis: EPA proposes a sensible approach to identifying chemicals of concern

By / Published: September 13, 2011

Richard Denison, Ph.D., is a Senior Scientist.  Thanks to my colleagues Jennifer McPartland and Allison Tracy for their analysis of the EPA proposal discussed in this post.

Last week, the Environmental Protection Agency (EPA) held stakeholder meetings to get public input into the criteria it will use to identify additional chemicals of concern beyond the 11 chemicals or chemical classes it has already identified.  EPA used these meetings (as well as an online forum open until September 14) as an opportunity for the public to respond to a “discussion guide” it issued in August that sets forth draft criteria and identifies data sources it intends to use to look for chemicals that meet the criteria.

The day before the EPA meetings, the American Chemistry Council (ACC) issued its own “prioritization tool” which lays out its own criteria and ranking system for identifying chemicals of concern.  This post will make a few observations about EPA’s proposal.  My next post will provide a critique of ACC’s proposed tool.

EDF and the Safer Chemicals Healthy Families coalition strongly support EPA in this endeavor – both for what it is, and for what it is not.    Read More »

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Chemical safety evaluation: Limitations of emerging test methods

By Jennifer McPartland / Published: June 14, 2011

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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