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I’ll Trade You: Water Quality Science Edition

2014 July 10

By Marguerite Huber

Landsat image of Chesapeake Bay

Chesapeake Bay watershed includes six states and the District of Columbia. Image: NASA/Goddard Space Flight Center Scientific Visualization Studio

The outcome of a trade can sometimes be the luck of the draw. You may not have gotten a better sandwich for the one you traded at lunch, or the all-star pitcher your team acquired in that mid-season trade may turn out to be a bust.

On the other hand, the best kind of trade is one where everybody wins. EPA researchers are helping bring just that kind of trade to improve water quality.

Chesapeake Bay is an expansive watershed that encompasses some or all of six states and the District of Columbia. High levels of nutrients flowing in from all over that expansive watershed decrease oxygen in the water and kill aquatic life, creating chronic and well-known dead zones.

To help, EPA established the Chesapeake Bay Total Maximum Daily Load (TMDL), which sets a cap on nutrient and sediment emissions to restore water quality, ensure high quality habitats for aquatic organisms, and protect and sustain fisheries, recreation and other important Bay activities.

Recent innovations in Chesapeake Bay and elsewhere have promoted a new type of trading, called water quality trading, to meet watershed-level reductions in nutrient pollution. The goal is to facilitate individual flexibility and responsiveness while creating incentives to reduce overall nutrient flow from both agricultural and urban areas.

Here is how water quality trading would work…

Farmers and wastewater treatment plants have the opportunity to team up to collectively meet the water quality goal by reducing nutrients. While both entities have their own baseline nutrient emission level they must shoot for, they can gain tradable credits if they do better. A farmer that plants nitrogen-absorbing crops such as barley and wheat can sell the credits they gain to a wastewater treatment plant that needs to reduce its own emissions.

Silhouette of kids on dock at sunset

A healthy Chesapeake is a win for everybody!

Trading is based on the widely different costs it can take to control the same kind of pollutant, depending on its source and location. For example, upgrading wastewater treatment plants and ripping up urban streets to replace leaky stormwater drainage pipes could cost billions of dollars. On the other hand, planting new or different crops is much less expensive.

Like the TMDL itself, the development of the water trading system began with science. EPA-supported scientists and economists developed a computer model to find the least costly mix of pollution-reduction options across the watershed for meeting the TMDL. The model also has been used to explore how different trading policies could help to meet TMDL requirements, and as the basis for analyzing policies leading to the nutrient trading guidelines for Chesapeake Bay.

Overall, water quality trading depends on cooperation across the watershed to help achieve faster, less expensive pollutant reductions that improve the Bay’s water quality. It’s a win-win for everybody.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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The Dose Makes the Poison – or does it?

2014 July 8

By Kacee Deener Three images arranged horizontally: grade school students in classroom; girl with arms raised; bicyclists at sunriseWhen I was a graduate student, one of the first lectures in my toxicology class was about the history and basic principles of toxicology. We learned about Paracelsus, the 16th century physician-alchemist known as the father of toxicology, and how he coined the phrase “the dose makes the poison.” This has been a central tenant of toxicology and an important concept in human health risk assessment. The more we learn about the health effects of chemicals, however, the more we realize things may not be quite this simple.

I recently wrote about identifying the hazards of chemicals. Once we know what such hazards are, how do we know what levels of exposure will cause those health effects in humans? This is a really important question. To answer it, scientists do something called dose-response analysis, the next step in the human health risk assessment process. To do this, scientists calculate how different amounts (exposures or doses) of a chemical can impact health effects (responses) in humans.

Scientists measure these amounts both externally (outside the body) and internally (inside the body). External measurements, exposure levels, are the amount of a chemical in an external media, such as air, water, or soil. Internal dose refers to the amount of a chemical that actually gets into a person’s body after ingesting or inhaling something (like food or air) that contains the chemical.

Often, as the internal dose or exposure level increases, the response or health effect also increases—though there are exceptions to this. Additionally, sometimes we don’t have data about effects at doses lower than what might be tested in studies, so we have to mathematically extrapolate to estimate the effects below the observed data. Traditionally we have done this using different approaches for cancer versus other health effects, but this may change as our scientific understanding of disease processes improves.

Why is dose-response assessment important? First, it helps us understand what happens in the human body at different levels of exposure to a chemical, and it allows us to see that relationship presented graphically. Second, it allows us to derive toxicity values (described in the table below) that become important when we develop a complete risk assessment.

Toxicity Value Name Description
Reference Dose (oral exposures) The amount of a substance that one can ingest every day for a lifetime that is not anticipated to cause harmful health effects.
Reference Concentration (inhalation exposures) The amount of a substance that one can breathe every day for a lifetime that is not anticipated to cause harmful health effects.
Oral Slope Factor An estimate of the increased cancer risk from a lifetime of oral exposure to a substance.
Inhalation Unit Risk An estimate of the increased cancer risk from a lifetime of inhalation exposure to a substance.

We want to make sure we are protective of sensitive groups of people when we calculate toxicity values. To do that we may apply scientifically-based factors to account for uncertainty in various areas, such as differences between animals and humans (if we start with animal data), differences among humans (such as genetics, life stages, etc.), and scientific data gaps (for example, certain health endpoints that have not been evaluated). In EPA’s Integrated Risk Information System (IRIS) Program, we’ve started developing multiple toxicity values for different organ systems or health effects seen in the data.

The toxicity values resulting from dose-response assessment are used as part of a larger calculation to estimate risk from exposure to environmental contaminants. I’ll talk more about that in a few weeks. Until then, check out an example of dose-response assessment in Section 2 of the IRIS assessment of benzo[a]pyrene. And read more about dose-response assessment on the Agency’s risk assessment website.

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, and EPA does not verify the accuracy or science of the contents of the blog.

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Improving IRIS: Please Join the Conversation

2014 July 8

By Kacee Deener

IRIS graphic identifier

Over the past few years, EPA has embraced a major new effort to enhance its Integrated Risk Information System (IRIS) Program to improve the scientific foundation of assessments, increase transparency, and improve productivity. IRIS is a human health assessment program that evaluates information on health effects that may result from exposure to environmental contaminants. Information from IRIS is used by EPA and others to support decisions to protect human health.

We think we’ve made terrific progress so far, and we were thrilled that the National Academies’ National Research Council (NRC) agrees. They spent the past two years reviewing IRIS, and in May 2014, they issued a report highlighting our progress and offering recommendations on keeping the progress moving forward (Assistant Administrator Lek Kadeli recently wrote about this on EPA Connect, the Agency’s leadership blog).

In their report, the NRC commended EPA for its substantive new approaches, continuing commitment to improving the process, and successes to date. They noted that the IRIS Program has moved forward steadily in planning for and implementing changes in each element of the assessment process. They also provided several recommendations which they said should be seen as building on the progress we’ve already made.

We are happy to announce that we are taking additional steps to improve the IRIS Program. In October, we will hold a public workshop to discuss specific recommendations from the NRC’s report, which fall under the three broad topics below. We invite you to provide early input by commenting on this blog post, which is the first in a new IRIS blog series geared toward generating online scientific discussion about issues relevant to the IRIS Program. We plan to use blog posts like this more in the future to get your input.

  • Topic 1 – Refining systematic review methodology, including methods to evaluate risk of bias. The NRC stated that EPA should continue to document and standardize its process for evaluating evidence and recommended EPA develop tools for assessing risk of bias in human, animal, and mechanistic studies that are used as primary data sources. The NRC noted the limitations of available approaches for use with observational (nonrandomized) studies, and advocated exploration of differences in applying methods for evaluating epidemiological studies to controlled experimental in vivo and in vitro studies. They noted that these approaches will depend on the complexity and extent of data on a chemical and the resources available to EPA, and that additional methodological work might be needed to develop empirically-supported evaluation criteria for animal or mechanistic studies.
  • Topic 2 – Advancing methodology to systematically evaluate and integrate evidence streams. The NRC stated that EPA should continue to improve its evidence-integration process incrementally, and to enhance its transparency. The committee provided several alternatives for organizing evidence of hazard potential and recommended that the IRIS Program should either continue with the guided-expert-judgment process for evaluating evidence, but make its application more transparent, or adopt a structured approach with rating recommendations. The committee also encouraged the IRIS Program to simultaneously expand its ability to perform quantitative modeling, specifically using Bayesian methods, to inform hazard identification.
  • Topic 3 – Combining quantitative results from multiple studies, presenting appropriate quantitative toxicity information, and advancing analyses and communication of uncertainty. The committee encouraged the IRIS Program to continue its shift towards the use of multiple studies for dose-response assessment, but with increased attention to judging the relative merits of mechanistic, animal and epidemiologic studies, with an ultimate goal of developing formal methods for combining studies and deriving toxicity values in a transparent and replicable manner. The NRC stated that it is critical to consider systematic approaches to synthesizing and integrating the derivation of a range of toxicity values in light of variability and uncertainty. Integral to this latter goal is the NRC recommendation to develop methods to systematically conduct uncertainty analyses and to appropriately communicate uncertainty to the users of IRIS assessments.

We’re interested in hearing your thoughts about the NRC recommendations above. For example, do you have ideas about how we should move forward to address the recommendations in these topic areas? Do you have scientific suggestions for the IRIS Program to consider related to these topics? Do you have suggestions for who we should ask to speak at the workshop? Please add your thoughts, ideas, and suggestions in the comments below and join the conversation!

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, and EPA does not verify the accuracy or science of the contents of the blog.

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Interested in air sensors? Tune in to our webinar!

2014 July 7

By Dustin Renwick

Soccer goalie with outstretched hand

Goal? Sensors will help make the call.

Sensors are everywhere these days. Some determine whether the ball has crossed the goal line in the World Cup. Others help EPA, state and local agencies, and communities take a more in-depth look at air quality.

Commercial manufacturers continue to develop low-cost air sensors that are portable and can relay data in nearly real-time. EPA researchers have begun to develop sensors and test their potential applications. Join our webinar on July 8 at 1 p.m. ET to learn more.

EPA researcher Ron Williams presented a small set of findings at the 2014 Air Sensors workshop in June, the fourth in a series of workshops designed to explore the opportunities and challenges associated with next-generation air quality monitoring technologies and data. Check out the Twitter feed for a look at the discussions that happened last month.

The sensor team, including Williams, has tested these new technologies in the laboratory and in the field. The group assessed how the sensors performed under a range of environmental conditions and with several different kinds of air pollutants. The team also evaluated the technical side of the sensors, including features such as data transmission and battery life.

EPA's Village Green Project, a solar-topped bench with air sensors

EPA’s Village Green Project

Williams will share much more information on the webinar, including the progress of the Village Green Project air monitor prototype and newly published reports about the use of these low-cost technologies.

“We have a lot to learn about sensors, their use, and how they can be applied for a wide variety of air monitoring applications,” Williams said.

“This presentation will give viewers an opportunity to understand what we at EPA have been doing and where the future lies in better understanding sensors and their potential applications.”

If you have any interest in the how sensors are transforming clean air science, the webinar will be worth watching!

About the author: Dustin Renwick works as part of the innovation team in the EPA Office of Research and Development.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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DISCOVER-AQ: Tracking Pollution from the Skies (and Space) Above Denver

2014 July 3
NASA four-engine turboprop P-38 takes to the sky

NASA four-engine turboprop takes to the sky for clean air science.

 

EPA scientists have teamed up with colleagues from NASA to advance clean air research. Below is the latest update about that work. 

Denver is the last of four cities in a study by EPA and partners that will give scientists a clearer picture of how to better measure air pollution with instruments positioned on the earth’s surface, flying in the air, and from satellites in space.

The NASA-led study is known as DISCOVER-AQ, and is being conducted July 14 to August 12 in Denver.  The research began in 2011 with air quality measuring conducted in the Baltimore-Washington, DC, area followed by a field campaign in California’s San Joaquin Valley and Houston in 2013.

Right now, monitoring for pollutants such as sulfur dioxides, nitrogen oxides, particulates and ozone is done by ground-based systems strategically located across the U.S. to measure air quality in metropolitan areas and on a regional basis. Researchers want to tap satellite capabilities to look at pollution trends across wide swaths of the country.

“The advantage of using satellites is you can cover a wider area,” said Russell Long, an EPA project scientist.  “But right now, it’s hard for satellites to determine what air pollutants are close to the ground.”

Satellites could be an important tool for monitoring air quality given the large gaps in ground-based pollution sensors across the country and around the world. Improved satellite measurements should lead to better air quality forecasts and more accurate assessments of pollution sources and fluctuations.

However one of the fundamental challenges for space-based instruments that monitor air quality is to distinguish between pollution high in the atmosphere and pollution near the surface where people live.

Ground-based air sensor station

Ground-based air sensor station from the study’s previous Baltimore and Washington area component.

The ground-based sensor readings taken by EPA and other partners in DISCOVER-AQ will be compared to air samples taken by NASA aircraft flown between 1,000 and 15,000 feet in the skies above the Denver metropolitan area. EPA scientists are using the opportunity during the DISCOVER-AQ study to also test various types of low-cost and portable ground-based sensors to determine which ones work the best.

“Our goal is to evaluate the sensors to see how well they perform,” Long said. “By including more sensors it increases our understanding of how they perform in normal monitoring applications and how they compare to the gold standard (for measuring air quality) of reference instrumentation.”

New sensors could augment existing monitoring technology to help air quality managers implement the nation’s air quality standards.

Another big part of EPA’s involvement in DISCOVER-AQ is working with schools and academic institutions to develop a robust citizen science component for pollution monitoring. In Houston, hundreds of student-led research teams all worked to test the air pollution technology by taking regular readings at their schools when NASA aircraft flew overhead.

In Denver, most schools are out for the summer, but EPA researchers will be partnering with the Denver Museum of Nature and Science to share what they are doing in DISCOVER-AQ with the general public.

Long says he is also working with University of Colorado Boulder to look at a unique three-dimensional model of air pollution in the great Denver area. The end result of DISCOVER-AQ will be a   global view of pollution problems, from the ground to space, so that decision makers have better data and communities can better protect public health.

Learn More

EPA DISCOVER-AQ

NASA Discover-AQ Mission

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Modeling Cyanobacteria Ecology to Keep Harmful Algal Blooms at Bay

2014 June 26

By: Betty Kreakie, Jeff Hollister, and Bryan Milstead

Sign on beach warning of harmful algal bloom

U.S. Geological Survey/photo by Dr. Jennifer L. Graham

Despite a lengthy history of research on cyanobacteria, many important questions about this diverse group of aquatic, photosynthetic “blue-green algae” remain unanswered.  For example, how can we more accurately predict cyanobacteria blooms in freshwater systems?  Which lakes have elevated risks for such blooms?  And what characteristics mark areas with high risks for cyanobacteria blooms?

These are important questions, and our ecological modeling work is moving us closer to finding some answers.

The gold standard for understanding cyanobacteria in lakes is direct measurements of certain water quality variables, such as levels of nutrients, chlorophyll a, and pigments.  This of course requires the ability to take on site (“in situ”) samples, something that is not possible to do for every lake in the country.  Our modeling work is focused on predicting cyanobacterial bloom risk for lakes that have not been directly sampled.

We are using remote sensing and geographic information systems (GIS) data to model bloom risk for all lakes in the continental United States.  The work is also starting to shed light on some of the landscape factors that may contribute to elevated predicted bloom risk.  For example, we know that different regions have different predictive risk.   We are also learning about how lake depth and volume, as well as the surrounding land use impact cyanobacteria abundance.

In addition to our national modeling efforts, we are collaborating with others on smaller scale and more focused studies at regional and local scales.  First, we are partnering with other EPA researchers to develop time-series models using data gathered frequently and over a long time by the U.S. Army Corp of Engineers.  By using these data, we expect to tease apart information about annual timing and the intensity of blooms.  We can also explore aspects of seasonal variability and frequency. Lastly, we are starting to explore ways to use approximately 25 years of data collected by Rhode Island citizen science as part of the University of Rhode Island’s Watershed Watch program.  We hope to mine these data and uncover indicators of harmful algal bloom events.

With all this work, we and our partners are adding new chapters to the long history of cyanobacteria research in ways we hope will help communities better predict, reduce, and respond to harmful blooms.

About the Authors: EPA ecologists Betty Kreakie, Jeff Hollister, and Bryan Milstead are looking for ways to decrease the negative impacts of cyanobacteria and harmful algal blooms on human health and the environment.

NOTE: Join Betty Kreakie, Jeff Hollister, and Bryan Milstead for a Twitter chat today (June 26) at 2:00pm (eastern time zone) using the hashtag #greenwater. Please follow us @EPAresearch.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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

2014 June 25

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, and EPA does not verify the accuracy or science of the contents of the blog.

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.

Tool Saves Millions of Dollars After Wildfire

2014 June 25

By Marguerite Huber

Wildfire conflagration on forested hillsides

Wildfire seasons are getting longer and burning more acres. Photo by USDA Forest Service.

Fueled by drought, disease, and suburban sprawl, wildfire seasons are getting longer and burning more acres of land. Last August, the Elk Complex wildfire burned more than 130,000 acres east of Boise, Idaho. Nearly 75% of the burned area had high to moderate burn severity, threatening the ecosystem and the region’s water. Substantial fires have already flared up this summer around San Diego, California, and Flagstaff, Arizona.

Once a fire is about 80% contained, scientists and other experts from the Department of the Interior’s National Interagency Burn Area Emergency Response (BAER) team can go into the region and help develop emergency stabilization plans. They are aided by a resource—the Automated Geospatial Watershed Assessment (AGWA) tool—developed by researchers from EPA, the Agricultural Research Service (part of the U.S. Department of Agriculture), and the University of Arizona.

Originally developed as a computer model for use managing and analyzing water quantity and quality, fire recovery teams are now tapping it to identify potential threats to people, wildlife, and the land from post-fire flooding and erosion.

Watershed managers use AGWA to identify and assess downstream impacts and risks from increased flooding and erosion resulting from fire-related changes to habitats and soils. The tool can also be used to target restoration efforts, such as where to apply mulch and seed with native plant stock, to reduce such downstream risks.

“AGWA is a good example of a science product developed between two leading federal research agencies with mutual interest,” said EPA research ecologist William Kepner. “The tool provides a practical application with immediate benefits.”

For the Elk Complex wildfire, the BAER team estimates it saved approximately $7,000,000 to $8,000,000 by using AGWA to target 2,000 acres for treatment instead of the initial 16,000 acres identified through more traditional methods.

“AGWA is able to help the team develop a stabilization plan where post-wildfire impacts pose immediate and significant threats to people and property,” Kepner adds.

Additionally, the emergency response team has successfully used the tool for post-fire watershed assessments following fires in Arizona, New Mexico, California, Idaho, and Washington. More than 8,000 users, spanning six continents, 163 countries, and 4,903 cities, have registered to use the Automated Geospatial Watershed Assessment tool .

The AGWA tool has been included as an ecosystem services analysis tool in the new EPA EnviroAtlas, and can be downloaded here. It provides an important resource for meeting the challenge of longer, more destructive wildfire seasons.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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.

Open Science and Cyanobacterial Research at EPA

2014 June 23

By: Jeff Hollister, Betty Kreakie, and Bryan Milstead

Green, algal-filled pond

Algal bloom containing cyanobacteria.

It wasn’t long ago that science always occurred along a well-worn path. Observations led to hypotheses; hypotheses led to data collection; data led to analyses; and analyses led to publications. And along this path, data, hypotheses, and analyses were held close and, more often than not, the only public-facing view of the research was the final publication.

Science has come a long way with this model.  However, it was conceived when print was the main media and most scientific questions could be investigated by few scientists over a short period of time.

Then came computers. Then came the internet.

Just like in every other aspect of modern life, these advances are greatly impacting science. It has changed who conducts our science, how we share it, and how others interact with scientific information. All of these changes are playing out through the increasing openness of all parts of the scientific process.

This broad area has been defined as having several components. These components suggest that “open science”:

  • is transparent (and, of course, open)
  • includes all parts of research (data, code, etc.)
  • allows others to repeat the work
  • should be posted on an open and accessible website (while protecting Personally Identifiable Information, etc.)
  • occurs along a gradient (i.e. not just a binary open vs. not open)

At EPA, we are learning how to make our research on cyanobacteria and human health (for more info join our webinar) meet those criteria.  We are implementing open science in three ways: (1) making our work available via open access publishing; (2) providing access to the code used in our analysis; and (3) making our data openly available.

Several members of our research group have embraced open access options for publishing their research. For instance, our colleague Elizabeth Hilborn and her co-authors published results of their study—examining a group of dialysis patients following exposure to the cyanobacteria toxin microcystin—in one of the pioneering open access journals, PLoS ONE. Also in PLoS ONE, EPA scientist Bryan Milstead and his collaborators published a modeling method to combine the U.S. Geological Survey’s SPARROW model (a modeling tool for interpreting regional water-quality monitoring data), lake depth, lake volume, and EPA National Lakes Assessment data to estimate nutrient concentrations.

As our work progresses, we will continue to choose open access journals. In our experience, this has allowed our research to reach a larger audience and we can more easily track the impact through readership levels using available tools such as PLoS Article Level Metrics.

We are also sharing our data. Currently, this is accomplished through supplements added to publications and through sites such as the EPA’s Environmental Dataset Gateway. We plan to expand these efforts via data publications, version-controlled repositories, and through the development of Application Programming Interfaces (APIs) that provide access to data for developers and other scientists.

The goal of these efforts, and more (stay tuned for a future post on how coding fits in to open science), is to increase the reproducibility of our work (but challenges remain), reach broader audiences, and eventually have a greater impact on our understanding and management of harmful algal blooms.

About the Authors: EPA ecologists Jeff Hollister, Betty Kreakie and Bryan Milstead study greenwater for a living. If you have questions for them, join the webinar on June 25th or follow the twitter chat on June 26th using #greenwater.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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.

Wetlands: Earth’s Kidneys

2014 June 19

By Marguerite Huber

Stream restoration research

Stream restoration research

Our organs are vital to our health, with each one playing a significant part. Kidneys, for instance, filter our blood to remove waste and fluid. Wetlands are often referred to as “Earth’s kidneys” because they provide the same functions, absorbing wastes such as nitrogen and phosphorous. When excess amounts of these substances—nutrient loading—flow into waterways it can mean harmful algal blooms, hypoxia, and summer fish kills.

Recognizing the importance of wetlands, many communities are taking steps to protect, restore, and even create wetlands.

For example, many stream restoration projects include constructing wetlands to absorb stormwater runoff and absorb excess nutrients and other pollutants that flow in from a host of sources across the watershed (known collectively as nonpoint source pollutants).

These constructed wetlands can provide key elements to urban stormwater management because they help reduce the impacts of runoff after a rainstorm or big snowmelt event. Such runoff typically transports high concentrations of nitrogen and phosphorous and suspended solids from road surfaces into waterways.

One such type of wetland that may provide these kinds of benefits is the oxbow lake, so named because of their curved shape. These form naturally when a wide bend in a stream gets cut off from the main channel, but EPA researchers are taking advantage of a couple of oxbow wetlands created during stream restoration activities at Minebank Run, an urban stream in Baltimore County, MD.

The researchers are studying the oxbow wetlands to quantify how effective such artificially created wetlands are at absorbing nitrogen and phosphorous in an urban setting. If these types of wetlands are effective, then deliberately constructing oxbow wetlands could be an important nutrient management strategy in such landscapes.

From May 2008 through June 2009, the researchers analyzed water, nitrate (a form of nitrogen pollution), and phosphate flow during four storms to better understand the impacts of hydrology on the potential for the two oxbow wetlands and the adjacent restored streambed to absorb or release nutrients.

The results suggest that oxbow wetlands in urban watersheds have the potential to be “sinks” that absorb and store nitrogen. They also reinforced information pointing to the dynamic hydrologic connection linking water and nutrient flow between streams and nearby oxbow wetlands, findings that if confirmed through further investigation can be used to improve restoration efforts that improve water quality across entire watersheds.

When it comes to phosphorus, the researchers found that oxbows don’t function as “sinks,” but “sources,” that contribute a net increase of the nutrient. They hypothesize that this is because the nutrient is released from wetland sediments during storms or other similar events. Future studies are needed to investigate the magnitude of phosphorous release, and how important that contribution is across the watershed.

Just like how our kidneys are an essential aspect of the human body, wetlands are an important aspect of nature. Retaining additional nutrients and treating non-point source pollutants help give natural and constructed wetlands the affectionate nickname of “Earth’s Kidneys.”

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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.