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EPA Research: April 25, 2017

Land and Sea: Linking Ecosystem Services with Local Concerns in Guánica Bay Watershed, Puerto Rico  

The health of the coral reefs in Puerto Rico’s Guánica Bay is threatened by water quality issues. Many of these issues stem from sediment and nutrient pollution flowing off of the surrounding watershed. To support a preservation effort, EPA researchers have been leading and conducting studies to better understand the links between Puerto Rico’s coral reefs, the water quality of Guánica Bay, and land use across the watershed. 

EPA researchers saw this work as an opportunity to conduct a novel study on how to link specific benefits that flow from the environment—defined as “ecosystem service supply”—with stakeholder engagement. In their study, published in the journal Ecological Indicators, researchers quantified and mapped how management of the watershed influences nature’s benefits to humans.

The maps the researchers created revealed how ecosystem service production is distributed throughout the Guánica Bay watershed, illuminating areas where watershed management would benefit both the community and the coral reef habitat offshore. For example, reforestation would help meet many of the community’s objectives that had been expressed—specifically improved air quality, the conservation of threatened wildlife, and the retention of rainwater—while also protecting the coral reef from land-based pollutants. The results of the study suggest that including ecosystem considerations and community concerns can help gain support for coastal management decisions. 

Extensive Mixture of Pollutants Found in U.S. Streams 

The health of our streams is a reflection of the overall quality of our nation’s waters. The extent of chemical contamination in streams is often a principal driver in whether a given stream is considered healthy or impaired. Chemical contaminants reach streams from many human activities such as farming, industry, sewage treatment, and urban runoff. Understanding the degree to which our streams are polluted with chemical contaminants is critical to developing effective plans to maintain, manage, and restore them. 

The mixture of compounds present in stream waters was the focus of two recent studies from EPA and U.S. Geological Survey. Researchers took samples from 38 streams across the United States. One study analyzed the samples for over 700 chemical contaminants, while the other study used a suite of in vitro bioassays to look for hormone receptor activity. They found organic contaminants at all sampling sites, including pharmaceuticals, insecticides, herbicides, and antibacterials, with many sites having hundreds of chemicals detected. Further, estrogen receptor activity occurred in nearly every site and several locations displayed androgen and glucocorticoid receptor activity. Additional study is needed to determine if the contaminants present and their concentrations pose a risk to aquatic life, the food chain, or humans. You can read more about this work in a recent article in Popular Science.

Building Towers and Partnerships in North Carolina

EPA scientists are partnering with Clean Air Carolina in Charlotte, N.C., and the Eastern Band of Cherokee Indians in Cherokee, N.C., to conduct citizen science air quality projects in these regions. The Clean Air Carolina project will help citizen scientists learn how to use low-cost air sensors and evaluate the reliability of their results. The citizen scientists will use a portable ozone sensor and compare its results to nearby air monitors. Clean Air Carolina recently posted an online video demonstrating the construction of the weatherproof sensor housing. 

In Cherokee, N.C., Cherokee Tribe members were trained by EPA scientists to use and evaluate the performance of a particulate matter sensor, and compare sensor results to federal air monitors in their region. EPA scientists plan to use the data from this project to develop both a user guide for comparing the citizen-collected readings to regulatory grade readings and a data evaluation tool that citizen scientists can use to improve the integrity and accuracy of the data they collect. These tools will be made available on the Agency’s online Air Sensor Toolbox. To learn more about these projects, see Citizen Science Air Sensor Project with Clean Air Carolina and the Eastern Band of Cherokee Indians Fact Sheet.

Improving Nutrient Retention in Streams and Rivers

Nutrient pollution is one of the most challenging problems facing our watersheds. When there is too much nitrogen and phosphorus in water, algae can grow faster than ecosystems can handle. This has serious public health, environmental, and economic impacts. Nearly two-thirds of coastal rivers and estuaries in the US have been significantly impacted by excess nutrients. Reducing nutrients at the source is not always possible, so EPA researchers are looking at how to increase the streams’ ability to adapt to theses excess nutrients. 

Nitrogen and phosphorus are harder to manage in areas where streams have been disconnected, lined in concrete, or buried in underground pipes. These adjustments make it harder for the stream to retain nutrients because it disconnects the stream from areas where the nutrients can sink into the ground. EPA researchers reviewed and synthesized studies that provide nitrogen and phosphorus retention data to determine if hydrologically restoring streams can increase the amount of nitrogen that the streams can retain. The study concluded that stream restoration strategies can potentially foster nutrient retention within disconnected streams and floodplains. Read the study here