A new continent-wide initiative is underway to better understand varying mercury levels in the environment. The Dragonfly Mercury Project is a “citizen science” initiative and a collaboration between the University of Maine, the United States Geological Survey, Dartmouth College, the University of Wisconsin-LaCrosse, and the National Park Service.
Mercury is an element that is widely distributed throughout the environment in varying forms and concentrations. Although it is naturally occuring, elevated levels can be released into the environment by human-caused processes. For example, coal combustion is the largest anthropogenic source of mercury being released to the environment in the U.S. Mercury is a natural constituent in coal; when coal is combusted for power production mercury is released into the atmosphere as a bi-product. Atmospheric mercury falls out onto the surrounding environment with precipitation and is eventually transported to bodies of water.
Globally, the largest source of anthropogenically-emitted Hg is artisanal & small-scale gold mining (source: https://www.epa.gov/internatio nal-cooperation/mercury- emissions-global-context#type). In the US, coal combustion (as you mention) is the largest single source: “In the United States, power plants that burn coal to create electricity account for about 42 percent of all manmade mercury emissions (Source: 2014 National Emissions Inventory, version 1, Technical Support Document (December 2016)(PDF)”
Atmospheric mercury deposited in waterways can become “methylated” and highly toxic in a complex process, which is assisted by bacteria. The “methylation” process occurs most readily in water with high concentrations of dissolved organic carbon and low pH. Toxic methylmercury is readily absorbed and accumulated in biological tissue working its way up the food chain from small aquatic organisms, to fish, waterfowl and humans.
So where do dragonflies fit in? The Dragonfly Mercury Project is looking at dragonfly larvae for information about mercury levels in national parks across the United States. Dragonfly larvae are ideal for tracking environmental mercury. They accumulate relatively high levels of mercury because:
- they spend most of their life cycle (several years) in a freshwater aquatic environment where mercury methylation occurs
- they are long-lived and eat many small insects, thereby “bioaccumulating” mercury over a long period
- they are found across North America, from Alaska, through Canada, to Florida.
The citizen science project employs the work of students and park visitors to collect the laravae. Once the method is learned, dragonfly larvae are much easier to collect than fish. Collecting them is also engaging for kids. That’s why the Dragonfly Mercury Citizen Science Project was started. The project now spans USA.
Scientists like dragonfly larvae as well, for a number of reasons:
- the larvae are relatively large, with plenty of material for laboratory analysis
- laboratory analysis is relatively inexpensive
- they provide a good representation of the variability of mercury concentrations across locations.
Want to learn more about the Dragonfly Mercury Project or get involved? Find out more here.
Thank you to Lakehead University doctoral student Nathan Wilson, studying under Dr. Rob Stewart, Department Chair for Geography and Environmental Science, for bringing the Dragonfly Mercury Project to the attention of Infosuperior.
There is very strong interest in learning more about the process of methylation. To date, much research has been undertaken about methylmercury, much of it associated with fish. In fact, the Ontario government produces a “Guide to Eating Ontario Fish” to identify the types and amounts of fish that are safe to eat. Mercury is the primary concern outlined in this document. Every State around Lake Superior also provides documentation about eating fish from inland lakes, as well as from Lake Superior. Again, mercury is a primary concern.