Mercury Pollution Uncovered in US National Parks

A citizen science program that began over a decade ago has confirmed the use of dragonflies to measure mercury pollution…

In the new scientific study spearheaded by a citizen science program, dragonflies revealed mercury pollution levels across US national parks.  The local research project has spurred the first nationwide survey of the toxic metal.  Given that the parks studied stretch across the entire U.S., including Alaska and Hawaii, the findings reflect levels of mercury throughout the country.

Results overview

As part of the decade-long study, researchers came up with the first-ever survey of mercury pollution in the U.S. National Park System. The research found that about two-thirds of the aquatic sites studied within the national parks are polluted with moderate-to-extreme levels of mercury

The study also found that faster moving bodies of water, such as rivers and streams, featured more mercury pollution than slower moving systems including lakes, ponds, and wetlands.

Backstory

The study includes data from thousands of larval dragonfly specimens collected from nearly 500 locations across 100 sites within the U.S. National Park System. The survey was collected from 2009 through 2018 as part of the national Dragonfly Mercury Project.

Methylmercury, the organic form of the toxic metal mercury, poses risks to humans and wildlife through the consumption of fish. Mercury pollution comes from power plants, mining and other industrial sites. It is transported in the atmosphere and then deposited in the natural environment, where wildlife can be exposed to it.

Fish and aquatic birds are commonly used to monitor mercury levels but are difficult to work with in a large-scale project because of their size, migratory patterns, and the diversity of species. Dragonfly larvae are easy to collect and make the citizen science research project possible.

What’s next

The national research effort, which grew from a regional project to collect dragonfly larvae, found that the young form of the insect predator can be used as a “biosentinel” to indicate the amount of mercury that is present in fish, amphibians and birds.  The finding will make it easier to conduct mercury research and could lead to a national registry of pollution data on the toxic metal.


 

Journal Reference: Collin A. Eagles-Smith, James J. Willacker, Sarah J. Nelson, Colleen M. Flanagan Pritz, David P. Krabbenhoft, Celia Y. Chen, Joshua T. Ackerman, Evan H. Campbell Grant, David S. Pilliod. A National-Scale Assessment of Mercury Bioaccumulation in United States National Parks Using Dragonfly Larvae As Biosentinels through a Citizen-Science Framework. Environmental Science & Technology, 2020; 54 (14): 8779 DOI: 10.1021/acs.est.0c01255


 

 

 

 

Post: April