Shenandoah National Park has joined in a nation-wide study to sample mercury levels in national parks in an effort to identify threats to natural resources. This national project engages local citizen scientists to collect dragonfly larvae from distinct sampling sites in order to allow for comparison between parks and to provide baseline data on the spatial distribution of mercury contamination in national parks. To date, more than 300 citizen scientists have contributed over 1,800 hours towards the National Park Service-wide study.
In late August, Shenandoah National Park staff was joined by local volunteers and researchers from the University of Virginia (UVA) to collect data on the mercury levels in dragonfly larvae at Piney River in the park’s north district and Staunton River in the park’s central district. The University of Maine will analyze the samples and results will be compared to data from participating NPS units across the nation. Other project partners include the U.S. Geological Survey, The Schoodic Institute, and the NPS Air Resources Division.
Dr. Ami Riscassi of UVA explains that, “Researchers are still trying to understand the fundamental drivers of mercury deposition and transport, and the Shenandoah National Park is the ideal place to do this. In this higher elevation, atmospheric mercury can be stored in the soils and potentially be a long-term source of mercury to downstream environments. Here at the top of the watershed, we are the first stop to understanding how changes in atmospheric mercury are going to affect water resources at the park and downstream.”
The sampling procedure involves collecting dragonfly larvae from the bottom of rivers or lakes with nets. As dragonflies spend up to five years of their lives in larval form, they have years to eat and accumulate mercury as they grow and develop. Dragonflies are predators that eat a lot of other insects, placing them relatively high in the food chain. For these reasons, dragonfly larvae build up higher levels of mercury than other water-dwelling insects.
Dragonfly larvae is a food source for many types of fish that then accumulate more mercury, and are then in-turn consumed by mammals, birds, and humans, posing an even greater threat to health. Because larvae are much easier to sample than fish, they provide an excellent source of information on the levels of mercury contamination in an area.
Mercury contamination in a remote national park environment often comes from atmospheric deposits from coal-burning power plants. Studying dragonfly larvae in Shenandoah National Park is an important first step in understanding the extent of mercury contamination in this portion of the Blue Ridge and how it compares to contamination in other national parks.
“Many thanks to all our local and national partners for getting this program started at Shenandoah National Park!” said Jalyn Cummings, Air & Water Program Manager at Shenandoah National Park. “I’m hoping this will be just the first in many years of mercury monitoring for Shenandoah.”
This sampling activity meets one of the goals the National Park Services (NPS) has set for the years leading up to our 100th Anniversary. The “Call to Action” (http://www.nps.gov/
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