nanomaterials

This Week in EPA Science

By Kacey FitzpatrickResearch Recap graphic identifier

Need an excuse to hang out inside? Here’s something to read while you stay out of the heat. Check out the latest in EPA science.

Foxes and Ecosystem Services at Western Ecology Division
Late this spring, a self-operated wildlife camera captured several photos of adult gray foxes carrying food items from surrounding wild lands onto the grounds of EPA’s Western Ecology Division Laboratory in Corvallis, Oregon. Find out what they were up to in the blog Foxes and Ecosystem Services at Western Ecology Division.

Investing in our Children’s Futures
To protect children from environmental threats and help them live healthier lives, EPA and the National Institute of Environmental Health Sciences created the Children’s Environmental Health and Disease Prevention Research Centers (Children’s Centers). Read about the five new Children’s Center grants in the blog Investing in our Children’s Futures.

The Northeast Cyanobacteria Monitoring Program
As cyanobacteria bloom incidence continues to increase, EPA strives to create and improve methods for bloom prediction, monitoring, and management. The Northeast Cyanobacteria Monitoring Program will help generate region-wide data on bloom frequencies, cyanobacteria concentrations, and spatial distribution through three coordinated projects. To learn more about the program read the blog The Northeast Cyanobacteria Monitoring Program: One Program, Three Opportunities for You To Get Involved!

If you do decide to head outside, don’t forget the sunscreen! Here’s a little lesson in sunscreen chemistry.

Suncreen and Sun Safety: Just One Piece of the Story
It’s not surprising that sunscreens are detected in pool water (after all, some is bound to wash off when we take a dip), but certain sunscreens have also been widely detected in our ecosystems and in our wastewater. So how is our sunscreen ending up in our environment and what are the impacts? Find out in the blog Suncreen and Sun Safety: Just One Piece of the Story.

And coming up next week:

Let’s Talk About Wildfire Smoke and Health
Monday, August 22nd at 1:30 p.m. EDT
There are over 20 wildfires currently burning in the United States. Join us for a twitter chat with EPA research cardiologist Dr. Wayne Cascio and health effects scientist Susan Stone, along with experts from the U.S. Forest Service and the Centers for Disease Control, to discuss wildfire smoke and health.

To join the twitter chat and ask questions, please use ‪#‎WildfireSmoke and follow @EPAAir. Get more details in the blog Let’s Talk About Wildfire Smoke and Health.

About the Author: Kacey Fitzpatrick is a writer working with the science communication team in EPA’s Office of Research and Development. She is a regular contributor to It All Starts with Science and the founding writer of “The Research Recap.”

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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Suncreen and Sun Safety: Just One Piece of the Story

By Susanna Blair

Blue towel and sunscreen lotion near the poolIt’s the end of summer, and you know what that means: it is hot and sunny! (And if you’re in DC like me, it also feels like a swamp.) Going to the pool is one of my favorite things to do to help beat the heat, and because UV radiation is a known carcinogen, I make sure to bring the items CDC recommends for sun protection:  protective clothing, a hat, sunglasses, and loads of sunscreen.

But where does all of that sunscreen go? It’s not surprising that sunscreens are detected in pool water (after all, some is bound to wash off when we take a dip), but certain sunscreens have also been widely detected in our ecosystems and in our wastewater. So how is our sunscreen ending up in our environment and what are the impacts?

Well, EPA researchers are working to better understand this issue, specifically investigating sunscreens that contain engineered nanomaterials and how they might change when exposed to the chemicals in pool water. But before I delve into that, let’s talk a bit about sunscreen chemistry and nanomaterials….

The best protection from UV radiation is a physical block, such as titanium dioxide, which is a common ingredient in sunscreen. This type of physical sunblock is often in the form of engineered nanomaterials , which are materials with dimensions between 1 and 100 nanometers engineered with unique properties for specific uses.  (To put a nanomaterial’s size into perspective, just take a look at the hair on your head – a single strand is between 80,000-100,000 nanometers thick.)

Many sunscreens contain titanium dioxide (TiO2) because it absorbs UV radiation, preventing it from damaging our skin. But titanium dioxide decomposes into other molecules when in the presence of water and UV radiation. This is important because one of the new molecules produced is called a singlet oxygen reactive oxygen species. These reactive oxygen species have been shown to cause extensive cell damage and even cell death in plants and animals. To shield skin from reactive oxygen species, titanium dioxide engineered nanomaterials are often coated with other materials such as aluminum hydroxide (Al(OH)3).

EPA researchers are testing to see whether swimming pool water degrades the aluminum hydroxide coating, and if the extent of this degradation is enough to allow the production of potentially harmful reactive oxygen species. In this study, the coated titanium dioxide engineered nanomaterials were exposed to pool water for time intervals ranging from 45 minutes to 14 days, followed by imaging using an electron microscope.  Results show that after 3 days, pool water caused the aluminum hydroxide coating to degrade, which can reduce the coating’s protective properties and increase the potential toxicity.  To be clear, even with degraded coating, the toxicity measured from the coated titanium dioxide, was significantly less than the uncoated material. So in the short-term – in the amount of time one might wear sunscreen before bathing and washing it off — these sunscreens still provide life-saving protection against UV radiation. However, the sunscreen chemicals will remain in the environment considerably longer, and continue to degrade as they are exposed to other things.

This study provides evidence that when released into the environment, nanomaterials undergo physical and/or chemical transformations – an important consideration when measuring the impact of these materials on public health and the environment. EPA researchers continue to do work to better understand the life cycle of engineered nanomaterials and the potential transformation of these products when they are no longer working to protect our skin.

 

About the author: Susanna Blair is a physical scientist in the Chemical Safety for Sustainability Research Program in the Office of Research in Development. Her primary role is to translate and disseminate EPA’s chemical safety research.

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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Scientist at Work: Dermont Bouchard, Ph.D.

EPA Scientist Dermont Bouchard, Ph.D., is working to better understand how tiny nanomaterials might be released into the environment. What he and his research partners are learning helps regulators and other decision-makers lower risks and better protect human health and the environment.

How does your science matter?

My research focuses on the fate of nanomaterials in the environment—tiny materials measured on the “nanoscale” that are about 100,000 times smaller than the width of a human hair.

The field of nanomaterials, which is relatively new, uses the unique properties of nanoscale materials to develop new products and technologies, including many used in our homes.

My colleagues and I are developing techniques to measure and model the fundamental processes that determine where these nanomaterials end up in the environment.

One of our roles as scientists is to supply some of the basic information about nanomaterials: their properties, persistence in the environment, and the state of these materials, so that regulators can make informed decisions to protect human health and the environment. We are working to identify which materials would be most likely to be released into the environment so we can focus on them for additional study.

If you could have dinner with any scientist, past or present, who would you choose and what would you like to ask them?

Carel J. van Oss, a Dutch scientist who has made a lot of significant contributions to colloid science Exit EPA Disclaimer. Colloid science is really the foundation for a lot of the nanomaterials work that is done right now.

On top of being such an accomplished scientist, he was also a talented forger. While he was in the Netherlands at the start of WWII, he forged documents that assisted hundred of Jews in escaping Nazi occupation. I would like to ask him how he dealt with the occupation and how he got to where he is today.

Keep reading Dr. Bouchard’s interview here.

Read more Scientist at Work profiles here.

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

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.