NLRA is partnering with the Merrimack Dragonfly Mercury Project to examine mercury levels in the Newfound Watershed, adding another layer to our long-term water quality monitoring initiatives.
How Mercury Moves Through the Food Chain
In New Hampshire, mercury pollution comes mainly from burning waste and fossil fuels. It enters the atmosphere and can travel long distances before falling to the ground in rain and snow. In the water, algae and bacteria can change mercury into a form called methylmercury. Small aquatic animals pick up methylmercury when they eat algae and bacteria. As larger animals eat those smaller animals, mercury builds up in their bodies and becomes more concentrated higher up the food chain. This means fish and other animals at the top of the food chain can have much higher mercury levels than the organisms they eat.
For people, eating fish with high levels of mercury can cause health problems, especially for developing children. Mercury can also affect wildlife that eat fish, like loons and eagles.
Why Dragonfly Nymphs?
The Merrimack Dragonfly Mercury Project measures mercury levels in dragonfly nymphs (the aquatic larvae of dragonflies) to track mercury pollution across the Merrimack Watershed, including the Newfound Watershed. Dragonfly nymphs are a great way to monitor mercury levels because they spend their entire larval stage in the water, don’t travel big distances, and, because they eat other aquatic animals, mercury builds up in their bodies over time.
A Closer Look at Newfound
In September NLRA staff and volunteers headed to Newfound’s largest tributaries, the Cockermouth and Fowler Rivers, to collect dragonfly nymphs that will give us a clearer picture of Newfound’s mercury levels. Mercury in the collected nymphs will be measured at Dartmouth College, along with samples from other locations in the Merrimack River Watershed, to get a sense of mercury levels in lakes, rivers, and streams. This effort is part of a larger, nation-wide project to monitor mercury levels and protect human health and the environment.
Learn more by visiting The Merrimack Dragonfly Mercury Project and the nationwide Dragonfly Mercury Project.