It All Starts with Science

Aug 31, 2016

Reduce, Reuse, Recycle (our Water Sources): Water Conservation and Reuse Grants

By Christina Burchette

Recycling isn’t just for paper and plastic—did you know that there are ways to recycle resources like water too? This practice is especially relevant and useful in places that have a long history of water scarcity.

From the Dust Bowl of the 1930s to the present, the United States has experienced significant periods of drought, so finding ways to conserve the available water supply and safely recycle it has already been a regional priority. However, the continued threat of water scarcity has consequences ranging from locally mandated water conservation and use restrictions, to increased food prices, to more severe wildfires—making new solutions and strategies all the more important to the health of local communities, ecosystems, and economies.

That’s why EPA is helping drought-prone areas achieve water supply resiliency by researching new ways to recycle and conserve water while also understanding how these conservation and reuse efforts affect ecological and human health.

Recently, EPA awarded Science to Achieve Results grants to five institutions that are researching the human and ecological health impacts associated with water reuse, reclaimed water applications, and conservation practices. Each institution is investigating different aspects of water reuse and their effects on the environment and public health. Researchers will measure and evaluate the impact of water conservation strategies, such as

direct potable reuse, which is the process of reusing treated wastewater as drinking water without an environmental buffer;
indirect potable reuse, where recycled water is blended with a natural water source to be treated for use as drinking water;
aquifer recharge, where sites are constructed to collect stormwater so that it can infiltrate back into the ground; and
agricultural water reuse, which is when treated wastewater is used to fertilize and irrigate crops.

The frequency, intensity, and duration of drought events only continues to increase as we see the impacts of climate change. This pattern is expected to continue and shift outside of historical trends, making forecasting our water supply and quality more difficult.

This STAR grant research will help us better understand the potential impacts of water recycling and conservation. The results will also help inform water utilities, communities, agricultural producers, and policy makers, and others with the information and solutions they need to make informed water management decisions, thereby helping drought impacted communities create healthy and sustainable water supplies.

To learn more about these grants, see the press release and visit the grant page.

About the Author: Christina Burchette is an Oak Ridge Associated Universities contractor and writer for the science communication team in EPA’s Office of Research and Development.

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Aug 26, 2016

This Week in EPA Science

arsenic, back to school, living shorelines, nitrogen deposition, presidential environmental education awards, research recap, Researchers at work, upcoming events 0 Comments

By Kacey Fitzpatrick

Heading back to school? Get a little science refresher by checking out some of our research! Here’s the latest at EPA.

We’re Gonna Need a Bigger Shore
Sengekontacket Pond—the same pond where Jaws was filmed 41 years ago—and the adjacent salt marsh habitat at Felix Neck Wildlife Sanctuary are threatened by both impaired water quality and negative environmental changes, which have eroded almost ten feet of marsh in recent years. EPA teamed up with a several other organization to build a living shoreline as a natural approach to salt marsh restoration. Find out more about living shorelines in the blog The Use of Living Shorelines.

From Grasslands to Forests, Nitrogen Impacts all Ecosystems
To date, most U.S. biodiversity studies on the effects of nitrogen deposition had been focused on individual sites, where fertilizer was applied and small plots were monitored through time. That’s why EPA researcher Chris Clark and a team of scientists from EPA and collaborators are exploring the effects of nitrogen deposition in a first-of-its-kind study focused on multiple ecosystems across the nation. The study was recently published in Proceedings of the National Academy of Sciences. Read more about it in the blog From Grasslands to Forests, Nitrogen Impacts all Ecosystems.

Researchers at Work
Research engineer Michael Tryby develops and evaluates engineering processes for EPA tools that are used to protect public health and the environment. He currently works on our Stormwater Management Model, which is a widely-used tool that supports Green Infrastructure initiatives around the Nation and the world. Meet EPA Research Engineer Michael Tryby!

EPA Water Research Paper Earns Top Rank
A journal article by EPA’s Tom Sorg was ranked #1 on the Top 20 list of published papers on arsenic science in the journal Water Research. Read the journal article Arsenic species in drinking water wells in the USA with high arsenic concentrations.

Presidential Environmental Education Awards
EPA and the White House Council on Environmental Quality recognized 18 teachers and 63 students from across the country for their outstanding contributions to environmental education and stewardship. Read more about the recent awards ceremony in this press release.

Need more science? Check out some of these upcoming events at EPA.

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.”

Aug 24, 2016

The Use of Living Shorelines

ecosystem services, marsh restoration, nitrogen removal, public engagement, shoreline stabilization, social science, Sustainable and Healthy Communities Research 0 Comments

By Mary Schoell and Marnita Chintala

As we looked out over the water, sounds of laughter from distant kayakers could be heard over the soft ripples that lapped the eroded edge of salt marsh. From this view, it was easy to understand that Sengekontacket Pond—the same pond where Jaws was filmed 41 years ago—and the adjacent salt marsh habitat at Felix Neck Wildlife Sanctuary represented the quintessential beauty of Martha’s Vineyard. However, this area is threatened by both impaired water quality and negative environmental changes, which have eroded almost ten feet of marsh in recent years.

The need for shoreline stabilization inspired a collaboration with the Felix Neck Wildlife Sanctuary, the Shellfish Departments of Oak Bluffs and Edgartown, the University of Rhode Island, and a team of us from EPA’s Atlantic Ecology Division to address the social and ecological aspects of coastal restoration.

a group works on installing the living shorelines

The crew hard at work installing the living shoreline

For the ecological component we applied a natural approach to salt marsh restoration, called a living shoreline. This technique uses natural materials such as coconut fiber coir logs and oyster shell bags that cup the marsh edge (see photo to the right). These materials are arranged to reduce wave energy to both enhance the existing marsh and facilitate the growth of new salt marsh area. Because of concerns with nutrient loading in Sengekontacket Pond, the project has also provided us with the perfect opportunity to examine how the use of alternative technologies such as a living shoreline can aid in nitrogen removal.

Understanding changes in nitrogen, water, soil, plant, and animal health at our sites over time will provide novel information about the practicality and success of living shorelines in New England. The endeavor also incorporates a University of Rhode Island social science study about the public response to this type of restoration and how personal interests and values influence and define restoration success.

We designed and sewed our own biodegradable shell bags.

To date, we have installed two living shoreline areas. We have deployed close to 50 coir logs (12 ft long and 130 lbs each) and around 600 shell-filled bags (3 ft long and 30 lbs each) out onto the marsh this summer—making this surely one of the more physically demanding projects that we have gotten ourselves into here at the Atlantic Ecology Division.

Because this is a collaborative project, many stakeholders means many different values and needs. Although we designed this project as an experiment to answer specific quantitative questions about living shorelines, we quickly learned that compromise and communication are crucial for success. Felix Neck Wildlife Sanctuary values the preservation of nature and is committed to providing opportunities for the public to gain environmental awareness. To honor these goals, we tailored our sampling and monitoring methods to minimize the impact we have on the marsh landscape. To ensure that every piece of the project is environmentally friendly, we avoided the use of plastic shell bags and instead designed and sewed our own biodegradable bags. We have also created an informative poster so marsh visitors can learn about what we are monitoring along the shoreline and why it’s important to track these changes over time.

The project is at the interface of physical restoration, scientific research, social science, and public education. Not only will this living shoreline work help shape decision making in the context of shoreline stabilization techniques, but it will facilitate public awareness of salt marsh erosion and the need for natural shoreline restoration.

About the Authors: Mary Schoell is a student services contractor working with EPA’s Atlantic Ecology Division. Marnita Chintala is a Branch Chief at the Atlantic Ecology Division and is a Task Lead within the Sustainable and Healthy Communities research program.

Aug 23, 2016

Upcoming Events at EPA

Adverse Outcome Pathway, EPA drinking water workshop, RETIGO, small systems webinar, upcoming events, webinars 0 Comments

By Michaela Burns

Fall is just around the corner and so are these upcoming events at EPA!

13th Annual U.S. EPA Drinking Water Workshop
Tuesday, August 23rd at 8:30 a.m.-Thursday, August 25th at 12 p.m.

EPA, in cooperation with the Association of State Drinking Water Administrators, is hosting its annual drinking water workshop to support the efforts of state and local officials to assist small systems. The 13th annual workshop will provide in-depth training and information on various solutions and strategies for handling small system problems and compliance challenges. Register now to attend.

Adverse Outcome Pathway Knowledge Base
Thursday, August 25^th at 11 a.m. ET

EPA and its partners at the Organization for Economic Cooperation and Development’s are launching a project to develop the “Adverse Outcome Pathway Knowledge Base” (AOP-KB). The AOP-KB is a combination of individually developed platforms, synchronized and orchestrated in a way that gives users the possibility to capture, review, browse, and comment on adverse outcome pathways shared by the stakeholder community. Attend this event remotely or in person at EPA’s Research Triangle Park.

Removal of Multiple Contaminants: Biological Treatment and Combined Ion Exchange
Tuesday, August 30^th at 2:00 p.m. ET

In this month’s small systems webinar, Dr. Treavor Boyer from Arizona State University will give a presentation on combined ion exchange to remove dissolved organic carbon and hardness in drinking water. Nicholas Dugan from EPA’s Water Supply and Water Resources Division will then discuss capabilities of biological treatment for drinking water. Register now!

Bonus— A certificate will be offered for this webinar.

RETIGO Training Webinar
Wednesday, August 31^st at 1:00 p.m. ET

Curious about EPA’s Real-Time Geospatial Data Viewer, commonly known as RETIGO? Attend this webinar to learn the basics of this interactive tool that allows users to upload field data they have collected while in motion (walking, biking, or on a vehicle) and explore it visually by plotting the data on a map and/or graph to observe air quality trends. Register for the webinar.

Systems View of Nutrient Management-Nutrient Modeling
Wednesday, August 31^st at 2:00 p.m. ET

Check out this month’s Safe and Sustainable Water Resources research program webinar! Dr. Richard Ready of Montana State University will give a presentation on how agricultural best management practices aimed at reducing nutrient and sediment loads play an important role in restoring ecosystem function in the Chesapeake Bay. Register now!

For more events head on over to the EPA research event page.

About the Author: Michaela Burns is an Oak Ridge Associated Universities contractor and writer for the science communication team in EPA’s Office of Research and Development.

Aug 22, 2016

From Grasslands to Forests, Nitrogen Impacts all Ecosystems

air research, climate change research, PNAS 0 Comments

By Ashley Mayrianne Jones

Can there be too much of a good thing?

That’s the case with nitrogen, an essential element for plant growth that, in overabundance, can also be potentially damaging. Nitrogen moves from the air to the land, soil, and water via a process called nitrogen deposition. Atmospheric nitrogen deposition has increased ten-fold or more since pre-industrial levels due to increased emissions from the burning of fossil fuels, fertilizer use, and other human activities.

Once nitrogen is emitted into the atmosphere, it can travel vast distances and deposit in the environment, making it a national as well as local problem. Elevated nitrogen deposition can increase leaf biomass in the canopy, shading ground-dwelling plants from the sun. Additionally, physical and chemical reactions that occur when nitrogen compounds are deposited can lead to more acidic soils. Both effects restrict plant growth and increase competition for limited resources, resulting in a loss of local biodiversity.

To date, most U.S. biodiversity studies on the effects of nitrogen deposition had been focused on individual sites, where fertilizer was applied and small plots were monitored through time. It was unknown whether the resulting reductions in plant biodiversity at these small scales translated to meaningful changes at the landscape level. A series of recent studies had indicated that across the European continent, many ecosystems were experiencing reductions in plant biodiversity due to nitrogen deposition. However, it remained unclear whether the same held true in the U.S., which historically, has experienced lower atmospheric deposition levels.

That’s why EPA researcher Chris Clark and a team of scientists from EPA, U.S. Geological Survey, the U.S. Forest Service, the University of Colorado, and multiple other universities are exploring the effects of nitrogen deposition on herbaceous plants (those with non-woody stems such as grass) in a first-of-its-kind study focused on multiple ecosystems across the nation. The new research expands the focus to not only grasslands, but into habitats that have not received much attention, including the forest understory.

The study, recently published in Proceedings of the National Academy of Sciences, assesses how nitrogen deposition affects herbaceous plants at over 15,000 forest, woodland, shrubland, and grassland sites throughout the United States. The research addresses how physical, chemical, and climatic factors such as soil acidity, temperature, and precipitation can affect an area’s vulnerability to nitrogen deposition.

Nearly a quarter of the sites were vulnerable to nitrogen deposition-induced species loss, and those with acidic soils tended to be more vulnerable. At extremely low levels of nitrogen deposition, the number of individual plant species tended to increase. However, above a certain threshold level, or “critical load,” diversity began to decline.

The study indicated that on average, forests can tolerate slightly higher levels of nitrogen deposition than other ecosystems before showing a negative impact on biodiversity. The reasons for this are unclear, but scientists hypothesize part of the reason is that forest species living under the canopy are already adapted to low-light conditions and are less susceptible to shading effects caused by increased nitrogen. Both grasslands and forests, however, were quite vulnerable to nitrogen deposition, with critical loads in the range of current deposition levels.

Moving forward, EPA scientists and their partners will attempt to determine which individual plant species are most at risk, and which native and invasive species may increase with elevated nitrogen deposition.

Examining multiple ecosystems across the country gives us more information about how different locations may respond to the effects of nitrogen deposition and will help set monitoring and conservation priorities that protect plant biodiversity.

Learn more about EPA’s Air, Climate, and Energy Research.

About the Author: Ashley Mayrianne Jones is a student contractor and writer working with the science communication team in EPA’s Office of Research and Development.

Citation: Biological Sciences – Ecology: Samuel M. Simkin, Edith B. Allen, William D. Bowman, Christopher M. Clark, Jayne Belnap, Matthew L. Brooks, Brian S. Cade, Scott L. Collins, Linda H. Geiser, Frank S. Gilliam, Sarah E. Jovan, Linda H. Pardo, Bethany K. Schulz, Carly J. Stevens, Katharine N. Suding, Heather L. Throop, and Donald M. Waller. Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States. PNAS 2016 113 (15) 4086-4091; published ahead of print March 28, 2016, doi:10.1073/pnas.1515241113

Aug 19, 2016

This Week in EPA Science

Children's Centers, Citizen science, cyanobacteria, ecosystem services, nanomaterials, research recap, sunscreen 0 Comments

By Kacey Fitzpatrick

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.”

Aug 18, 2016

Foxes and Ecosystem Services at Western Ecology Division

ecosystem services, EPA's Western Ecology Division 3 Comments

By Randy Comeleo

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 (WED) Laboratory in Corvallis, Oregon.

A self-operated wildlife camera captures a recent photo of an adult gray fox returning to EPA Western Ecology Division with a camas pocket gopher.

Within a few weeks, photos from the camera revealed why the adults were carrying, and not consuming, their prey. The pair had denned in a quiet corner of our campus and were delivering food to six pups!

A self-operated wildlife camera captures a photo of nursing gray fox pups at the EPA Western Ecology Division.

The gray fox is a mesocarnivore – a mid-sized carnivore in which 50-70% of the diet is the flesh of another animal. Mesocarnivores are often more numerous when residing in close proximity to humans where their foraging activities can provide an important ecosystem service: keeping the level of property damage by rodents to an acceptable level.

We have been thrilled to observe these usually secretive small canids carrying food for their pups, basking in the sun, and even climbing trees! Gray foxes have adaptations such as short, powerful legs and strong hooked claws which enable them to climb trees and avoid larger predators like coyotes.

Four gray fox pups enjoy the early morning sun at the EPA Western Ecology Division (photo by Bonnie Smith).

The pups are now learning to hunt with their parents and will forage on their own in several weeks. The family will likely remain together until autumn, when the youngsters reach sexual maturity and head-out on their own.

About the Author: Randy Comeleo is an Ecologist for EPA’s Western Ecology Division research lab. He works primarily with the Air, Climate, and Energy research program as a Geographic Information System Analyst.

Aug 17, 2016

Investing in our Children’s Futures

Children's Centers, Children's Environmental Health and Disease Prevention Centers, National Institute of Environmental Health Sciences 1 Comment

By Jim Johnson

One of the greatest threats to children today comes from the environment. Exposure to pesticides, pollution, and heavy metals while in the womb or during early periods of development can cause serious and lifelong health concerns. To protect children from environmental threats and help them live healthier lives, EPA and the National Institute of Environmental Health Sciences (NIEHS) created the Children’s Environmental Health and Disease Prevention Research Centers (Children’s Centers). Teams of multidisciplinary experts at Children’s Centers across the country are looking at how children’s health is impacted by environmental and chemical exposures, epigenetics, non-chemical stressors and other factors with a focus on translating this research into practical information for public use.

This year, EPA and NIEHS are awarding five new Children’s Center grants. Research supported under these awards includes the interplay of air pollution, particulate matter and obesity on asthma among inner city children; prenatal and early childhood pollutant exposure and adverse birth outcomes; air pollution, polycylic aromatic hydrocarbons (PAHs) and adolescent cognitive, emotional, behavioral health outcomes; cumulative environmental exposures and increased risk for childhood acute lymphoblastic leukemia; and the effects of environmental contaminants on the microbiome and neurodevelopment. Each of the newly funded Children’s Centers is receiving between 1.25-1.5 million dollars per year for up to four years.

There are many obstacles to protecting children’s environmental health. Understanding the complexity of these challenges is just one way that EPA and its partners are reducing harmful environmental exposure and making the world a safer place for children and our communities.

About the Author: Dr. James H. Johnson Jr. is the Director of EPA’s National Center for Environmental Research.

Aug 16, 2016

The Northeast Cyanobacteria Monitoring Program: One Program, Three Opportunities for You To Get Involved!

Citizen science, cyanobacteria, Safe and Sustainable Water Research 1 Comment

By Sara Ernst

If you ever have noticed a waterbody with a layer of green scum coating its surface or a slick green film resembling a paint spill, you likely have witnessed a cyanobacteria bloom. Cyanobacteria, sometimes referred to as blue-green algae, are tiny organisms found naturally in aquatic ecosystems and numerous other environments. Typically, these organisms are harmless and go unnoticed; however, under certain conditions, cyanobacteria can form a dense mat or bloom on the surface of the water that may produce harmful toxins. These blooms and associated toxins pose a significant threat to humans, animals, and the ecosystem. They can cause illnesses, skin irritations, or worse and can threaten drinking water supplies and recreational opportunities. 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, covering the states of Rhode Island, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine, will help generate region-wide data on bloom frequencies, cyanobacteria concentrations, and spatial distribution through three coordinated projects: bloomWatch, cyanoScope, and Cyanomonitoring. Each project relies on the general public, citizen scientists, and trained water professionals to locate potential blooms and report applicable information, so we can improve cyanobacteria monitoring and learn more about harmful blooms in the Northeast.

The amount of time, equipment, and training needed to participate varies for each project. The simplest reporting tool to use is bloomWatch, a smartphone app that enables participants to help track cyanobacteria blooms by taking and submitting photos. All you need to do is download the app and you’re in business! bloomWatch teaches you what to look for, provides on-screen instructions on how to take good photos of blooms, and prompts you to answer some questions about the sighting. After submitting the photos and sighting details through the app, you can also send a bloom report to your state’s environmental agency.

The cyanoScope project helps scientists and water resource managers learn more about where and when blooms occur and what types of cyanobacteria are present across the region. With the appropriate gear and training, cyanoScope participants collect water samples of possible blooms, view the samples under a microscope, take photos of cyanobacteria, and upload the photos and sighting details to the cyanoScope project on iNaturalist.org. The cyanoScope community then helps to identify the cyanobacteria present.

The Cyanomonitoring project builds on bloomWatch and cyanoScope; it is the most involved project, and therefore contributes the most detailed information. In this project, professionals and trained citizen scientists use specific gear to monitor cyanobacteria concentrations in lakes and ponds to help determine where, when, and why cyanobacteria are blooming in those areas. Participants also assist in tracking regional trends resulting from climate and land use changes and assess waterbody and human health vulnerability to toxic cyanobacteria.

By participating in any of the three projects, you can contribute valuable data that will help scientists learn more about cyanobacteria blooms and how best to monitor them in the future. Interested in getting involved? Visit http://cyanos.org/ for more information on the Northeast Cyanobacteria Monitoring Program and each of the coordinated projects!

About the Author: Sara Ernst is an Oak Ridge Associated Universities contractor who works as the Science Communications Specialist in the Atlantic Ecology Division of EPA’s Office of Research and Development.

Aug 15, 2016

Sunscreen and Sun Safety: Just One Piece of the Story

chemical research, nanomaterials 1 Comment

By Susanna Blair

It’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.

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