Human Health Risk Assessment

A Message to IRIS Program Stakeholders: We Want to Hear From You!

By Kacee Deener

IRIS graphic identifierIn July 2013, EPA announced enhancements to our Integrated Risk Information System (IRIS) program to improve the scientific foundation of assessments, increase transparency, and improve productivity. Stakeholder engagement is an essential part of the enhancements, and since announcing them, we have held bimonthly public meetings to discuss scientific issues related to preliminary assessment materials and draft IRIS assessments. We announce these meetings well in advance on the IRIS website, and we publicly release any relevant materials about two months before the meeting is held. We also identify specific scientific issues related to the chemicals we are assessing.

Did you know that anyone can participate in these meetings? You can register to participate as a discussant on a specific scientific issue identified by EPA, or you can identify one of your own. Likewise, you can participate in the meetings more generally (i.e., not sign up for a specific scientific topic, but participate during discussion and open forum sessions). We don’t put together an invited panel for these meetings, and the agenda reflects those individuals who requested to participate in the scientific discussions.

IRIS meeting in a large conference room

EPA holds a public IRIS meeting.

We realize that you can never do too much where communication is concerned, so we use a variety of ways to publicize the meetings. They are announced on the IRIS website and through the IRIS Listserv and Human Health Risk Assessment research program bulletins, which reach more than 7,000 people combined. If you’re not on these lists, please sign up! We also use various social media platforms, including Twitter (follow IRIS and other EPA research on Twitter @EPAresearch).

We know that getting different perspectives on scientific issues is important, and we are exploring additional ways to reach out to scientists and other individuals who might be interested in participating in our meetings and contributing to the IRIS process.

We recognize that not all of our stakeholders have the resources to travel to a meeting. Because of that, for the past year and a half, every IRIS public meeting has also been available by webinar. We’ve also made some recent changes so that webinar participants can more fully engage in our meetings, including using telephone connections that allow webinar participants to actively participate in discussions.

EPA’s IRIS Program works on behalf of the American people, and anyone is welcome to add their voice to the conversation. We welcome your ideas about how to expand public access to and engagement in IRIS activities. We also welcome your input about how to obtain additional perspectives on the complex scientific issues that are discussed at IRIS bimonthly public science meetings. Join the conversation today by commenting on this blog post or sending us your ideas through the IRIS general comments docket.

As always, we want to hear from you!

About the Author: Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment.  She joined EPA 13 years ago and has a Masters degree in Public Health.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Is this Hazardous?

HHRAheader2

By Kacee Deener 

How do you know when something isn’t good for you? Sometimes it goes without saying (rattlesnake venom), and sometimes it’s not as obvious and requires deeper evaluation.

I recently kicked off a blog series about human health risk assessment and described its four-step process.  Remember that hypothetical factory? How do we know if the chemicals being released are harmful? We use a process known as “hazard identification” to identify the types of health problems a chemical could cause (like cancer or respiratory effects).

IRISExamples of two EPA programs that develop hazard identifications are:  (1) the Integrated Risk Information System (IRIS) program and (2) the Integrated Science Assessment (ISA) program.  Through IRIS, Agency researchers provide health effects information on environmental chemicals. ISAs provide health effects information to inform the National Ambient Air Quality Standards for the six criteria air pollutants.

So, how do we do this? We start by searching the scientific literature to compile all of the studies that look at a chemical’s effects. In IRIS assessments, we describe how we search the literature using, in part, a diagram.  You can see an example of that here (pages 1-2).  We then organize the information into the categories of health effects seen in the studies, (e.g., kidney or reproductive effects) and summarize certain features of each study, such as the level and route of exposure. We also look at each study’s quality (e.g., was the study designed and conducted well? was it peer reviewed?).  Finally, we evaluate the overall “weight of evidence” to answer the question “does the agent cause the health effect?”

In some cases, EPA has developed “descriptors” for doing this. The Preamble to IRIS assessments provides more information (you can see an example here on page xxii). In other words, we provide text describing how likely it is that a health effect is associated with a chemical exposure. For example, in the recent IRIS assessment of 1,4-dioxane, we found that the chemical is likely to be carcinogenic to humans. In our recent ISA for Lead, we found, among other things, that there is a “causal relationship” between lead exposure and cognitive function decrements in children and a “likely causal relationship” between lead exposure and inflammatory responses in adults.

We’ve been working to improve the way we systematically review evidence when identifying hazards.  In fact, we recently held a workshop on this topic. We’ve also started releasing the literature search strategy, along with evidence tables summarizing the critical studies, early in the process of developing an assessment. We follow that up with a public meeting to discuss the materials. We held the first of these meetings on December 12-13. Our next meeting is scheduled for April 23.  Join us to provide your input, and don’t forget to check back in a few weeks for my next post!

About the Author: Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment.  She joined EPA 13 years ago and has a Masters degree in Public Health.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Human Health Risk Assessment—What it’s all about

Three images arranged horizontally: grade school students in classroom; girl with arms raised; bicyclists at sunrise

By Kacee Deener 

Scientists need to be able to describe—in a way everyone can understand—what we do and why it’s important.  That’s one reason I’ve decided that I need to strengthen my “elevator speech” about what I do (human health risk assessment).  I will be writing blog posts over the next several weeks trying to explain human health risk assessment in plain language.

For this first post, I’ll introduce the concept of risk and explain why human health risk assessment is important.

Risk is something we all understand.  In fact, we all assess risk every day.  What is the risk of swimming in the ocean on a clear day?  Does the risk change if there are jellyfish? How about an approaching storm?  A shark swimming nearby?  We all understand these types of risk calculations at a very intuitive level.

Human health risk assessment isn’t so different.  It’s a process of characterizing the nature of an environmental risk (in many cases, a chemical exposure) and determining how large that risk is to humans.  It consists of four steps: (1) hazard identification, (2) dose-response assessment, (3) exposure assessment, and (4) risk characterization.  I will discuss each in future posts.

So why is human health risk assessment important?  Well, chemicals are a part of life.  Some exist naturally; some are made by humans and can be released to the environment.  They bring benefits to our lives, but like most things, they also come with risks.

Let’s consider a hypothetical example.  Suppose a factory produces something you use every day.  To make this product, the company uses several different chemicals, and some chemicals are produced during the manufacturing process as byproducts.  Some are released to the air and water and may get into the soil.  Let’s say this industrial site is located next to a river that leads to your local drinking water plant.  Are any of the chemicals in that water?  Are the levels safe for you to drink?  What about your child? What levels of the chemicals are safe for you to breathe?

Human health risk assessment helps answer questions like these.  It is a tool that helps local, state and federal governments make decisions about what levels of chemicals can be in drinking water; what additional controls are needed to keep levels emitted to the air at a safe level; and what levels need to be achieved to clean up a contaminated site.  From a public health perspective, this is pretty important stuff.

In the coming weeks, I’ll be posting more about EPA’s human health risk assessment work. Stay tuned for those posts, but in the meantime, you can learn more by going to http://go.usa.gov/KhCJ.

About the Author: Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment.  She joined EPA 13 years ago and has a Masters degree in Public Health.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Evaluating Studies to Understand if a Chemical Causes Cancer

IRIS graphic identifier

By Kacee Deener

When friends ask me what I do, I always mention the Integrated Risk Information System (IRIS) Program and explain that through IRIS, EPA scientists help protect public health by evaluating scientific information on the health effects that may result from exposure to environmental contaminants.  The questions inevitably come up—how do you do that, and what kind of information do you look at?

Scientists around the world contribute to the knowledgebase about the health effects of chemicals.  A particular area of interest has been chemicals’ potential to cause cancer.

Because EPA’s work must be grounded in the best possible science, we recently updated how we consider some of the cancer research of the Ramazzini Institute (RI), a laboratory in Italy known throughout the world for their extensive work in this area, completing cancer studies for more than 200 compounds.

A few years ago, the National Toxicology Program (NTP) identified differences of opinion between their own scientists and those from the Ramazzini Institute in diagnosing certain types of cancers in a study on methanol.  The scientific community—including EPA—was concerned, since Ramazzini data was included in IRIS evaluations.  We reviewed all of our IRIS assessments to determine which, if any, relied substantially on RI data; we found four that did, and we put those assessments on hold.

To follow up, EPA and the National Institute of Environmental Health Sciences cosponsored a group of scientists with expertise in evaluating tissue samples and making disease diagnoses, a Pathology Working Group (PWG), to review several Ramazzini Institute studies. They found some instances where respiratory infections in Ramazzini study animals made definitive diagnoses difficult, and disagreed with some Ramazzini diagnoses, primarily certain leukemias and lymphomas that had been identified. Therefore, EPA decided not to rely on RI data on lymphomas and leukemias in IRIS assessments. There was agreement, though, in diagnosing solid tumors, and EPA decided to continue to consider Ramazzini Institute solid tumor data in IRIS assessments.

This has been an important issue in the world of chemical risk assessment. Last week, this was highlighted once again when a paper authored by EPA scientists, Scientific Considerations for Evaluating Cancer Bioassays Conducted by the Ramazzini Institute, was published in Environmental Health Perspectives.  The article interprets Ramazzini Institute study results and compares their testing protocols with those used by other federal agencies.  The results were consistent with the PWG findings—Ramazzini Institute results for cancer endpoints other than lymphoma and leukemias, and some cases of tumors of the inner ear and cranium, are generally consistent with those of the National Toxicology Program and other laboratories.  The paper also notes that, while differences in Ramazzini Institute testing protocols can complicate the interpretation of study results, they may also provide chemical risk assessors with insights that might not be observed in other laboratories.

The short answer to my friends’ questions is that EPA works to use the best available science—from across the U.S. and around the world—to support IRIS and our other assessments designed to protect public health.

About the Author:  Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment, home of the IRIS Program.  She joined EPA 12 years ago and has a Masters degree in Public Health.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Writing Down IRIS

By Kacee Deener IRIS

As a scientist now working in science communications, I’m constantly surprised by the writing process.  You put something down on paper, revise it a few times, and then make tweaks here and there until you’re satisfied.  Then you look at it again later, and you make a few more changes.

Turns out lots of things in life are like that—including science programs.  In May 2009, EPA announced a new Integrated Risk Information System – or IRIS – assessment development process.

IRIS is an important program because it provides information on the health effects caused by exposure to chemicals in the environment.  People use IRIS, along with other science information, to inform decisions that protect public health across the U.S.

The new 2009 process was good for the IRIS Program.  But – as I’ve learned with writing – a few tweaks can make something even better.  Since 2009, we’ve learned a lot.  We’ve also received recommendations from the National Research Council (NRC) about improving IRIS assessments and about planning and scoping and stakeholder engagement in risk assessment.  So we’re making some common sense changes that will help us produce more high quality assessments in a timely and transparent manner.

In a nutshell, here’s what we are doing

  • Before beginning an assessment, we will meet with EPA’s regulatory programs – the folks who make decisions that help protect public health – to make sure we understand the big picture of why they need an assessment.
  • We will then hold a public meeting to discuss the plan for the assessment (so we better understand who needs it and why) and gather input about some technical aspects of developing the assessment (for example, are we concerned about people being exposed by breathing the chemical, ingesting it, or both?).
  • Next we will release a literature search for the chemical, evidence tables that summarize the critical scientific studies, and exposure-response figures that graphically depict the responses at different levels of exposure for each study in the evidence table. These materials highlight our thought process for determining which studies are most important for the assessment, help make sure we didn’t miss any important research, and help identify any potential scientific controversies early on.
  • We’re also using “stopping rules” so IRIS assessments are not delayed by ongoing research or scientific debate after certain points of the process have passed.
  • Finally, we’ve strengthened our practices for peer review and conflict of interest.

And this isn’t a complete list – you can read about all of the enhancements on our website.

These changes to IRIS are practical, common-sense improvements that emphasize scientific rigor and transparency.  They will also be good for our stakeholders, so like a well written story, it’s a win-win for everyone involved.

Like a committed science writer, we’ll always be revising whenever improvements are needed, but take a minute to check out the latest edition.  I think you’ll like the improvements.

About the Author: Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment, home of the IRIS Program.  She joined EPA 12 years ago and has a Masters degree in Public Health.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Sharing EPA Knowledge 7,000 Miles Away

By Abdel Kadry and Ila Cote

With an invitation from the U.S. embassy in Riyadh, two of my colleagues and I traveled to Saudi Arabia last month to provide risk assessment training to Saudi and other scientists in Riyadh and to participate in a scientific dialogue with Saudi government officials and others on the Global Methane Initiative.

Dr. John Vandenberg

For three days, we represented the United States in the Saudi International Environmental Technology Conference 2012, which was organized under the patronage of King Abdullah Bin Abdulaziz, the King of the Saudi Arabia. The conference was at King Abdulaziz City for Science and Technology (KACST), an independent scientific organization that encompasses both the Saudi Arabian National Science Agency and its National Laboratories.

KACST plays a pivotal role in the development of the National Science, Technology and Innovation policy and leads 62 government agencies and over 190 national programs and related projects for the development of the Kingdom’s strategic technologies. KACST also funds more than 400 independent research projects annually and acts as the Kingdom’s patent office.

The conference we attended hosted a large gathering of researchers, investors, decision makers and those interested in developing environmental technology. One goal was to facilitate achieving the priorities of the Saudi National Strategy for Environmental Technology.

The conference was organized around three main tracks:

  1. Air pollution and air quality.
  2. Waste & soil contamination & remediation.
  3. Climate change impacts and solutions.

My colleague, John Vandenberg, provided the plenary talk, and our team of three EPA scientists offered risk assessment training for the entire third day of the three day conference. Our training focused on the principles and application of risk assessment.

Dr. Ila Coate

We structured the training to include lectures combined with case studies, with a lot of time allotted to discussing the case studies.

We had excellent attendance and the participants were very engaged in the course material.  We also had the pleasure of meeting Saudi officials such as His Highness Dr. Turki AL Saud, the KACST vice president, who expressed considerable appreciation for the important international role that EPA plays in protecting human health and the environment. The team was also very proud that Dr. Ila Cote, who, as the only female speaker in the conference, provided much inspiration for the Saudi female scientists.

About the Authors:

Abdel Kadry is the Senior Advisor for Scientific Organizational Development and International Activities in EPA’s National Center for Environmental Assessment (NCEA).  Abdel has organized a series of international risk assessment training activities for NCEA, with a focus on developing countries.  Ila Cote, Senior Science Advisor in NCEA, and John Vandenberg, Director of the Research Triangle Park Division of NCEA, accompanied Abdel to Saudi Arabia to provide risk assessment training last month.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Protecting Human Health: That Explains It!

By Elizabeth Erwin

Child plays with water.

EPA's IRIS Program provides health effects information to help protect public health and the environment.

This past December, I had the opportunity to attend the annual Society for Risk Analysis (SRA) meeting in Charleston, SC. One of my responsibilities was to cover a symposium on EPA’s Integrated Risk Information System (IRIS) chaired by Becki Clark, Acting Director of my EPA office, the National Center for Environmental Assessment (NCEA).

Over the past year, I have become very familiar with IRIS, as a large part of my job is to communicate to the public, other federal agencies, and stakeholders what IRIS is, what it isn’t, and what it does to protect human health and the environment.

When I mention IRIS to friends and family, I’m often met with quizzical expressions. After several failed attempts at an explanation that included chemical names like “hexabromocyclododecane” and other scientific mouthfuls, I began giving them the bottom line: while IRIS assessments are not regulations or by themselves full risk assessments, the information they contain is an important basis for decisions that protect the health of all Americans.

Obviously, each of us has at some point taken a drink of tap water, inhaled deeply while enjoying an afternoon outside, or tracked soil into our homes. We perform these and dozens of other mundane daily activities without giving a second thought to potential harmful consequences, thanks in large part to EPA’s actions, many of which are based on IRIS human health assessments of more than 550 chemical substances.

Earlier this year, EPA finalized the long-awaited non-cancer assessment for dioxin, a major milestone for the Agency. Dioxins are toxic chemicals that exist in the environment naturally and can be released in greater quantities through forest fires, backyard burning of trash, certain industrial activities, and residue from past commercial burning of waste.

This final IRIS assessment is the latest effort in a successful, coordinated strategy by the Federal government that has reduced known and measurable air emissions of dioxins in the United States by about 90 percent since 1987.

Risk assessors, health professionals, and state, local, and international governments can now use these latest findings to guide future efforts to identify any residual sources of dioxin and protect public health.

Achievements such as this are what make me proud to be associated with EPA’s IRIS Program, especially when I get that oh-so-common question, “So, what do you do?” Attending the IRIS presentation reminded me that to answer that question, all I have to say is simply, “I help support the science that protects human health” – because that’s exactly what the IRIS Program does.

About the Author:  Elizabeth Erwin is a member of EPA’s science communication team where she helps make IRIS and other EPA science programs and assessments available and accessible.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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