Scientists already know that mercury can be a hazardous neurotoxin to both fish and anglers chowing down on their catches. But a plan to monitor the way the heavy metal cycles through the environment has taken on a new significance at a reservoir in northern Colorado.
Researchers had just finished installing the first-ever rainwater collector on the Front Range to measure mercury—when the High Park Fire started burning.
“Trees are living structures that have mercury in them, and when they burn that mercury is released into the atmosphere,” says Jesse Lepak, an aquatic research scientist with Colorado Parks and Wildlife.
Lepak and colleagues from Colorado State University realized that with the new collector so close to the forest fire, they’d be able to track the extra mercury in unprecedented detail. The Mercury Deposition Network even sent another collector to Horsetooth Reservoir—this time one that could take air samples directly. Along with the rainwater collector, which captures the mercury washed out of the air by rain, the dry collector can give a complete picture of atmospheric mercury levels.
“We don’t know much about dry deposition,” says Lepak, “and being that we’re in a very dry climate, it could represent a large contribution to the total mercury that we’re getting.”
Lepak says they will also be taking water and fish samples from throughout the reservoir to understand the full effects of the fire–and whether mercury levels will end up higher in popular sport fish like Walleye next year.
