Elevated Levels of Mercury Found in Fish in Western U.S. National Parks

Mercury has been discovered in fish in some of the most remote national park lakes and streams in the western United States and Alaska. Mercury levels in some fish exceeded U.S. Environmental Protection Agency health thresholds for potential impacts to fish, birds, and humans.

The information about mercury, and its appearance in protected areas considered to be relatively pristine and removed from environmental contaminants, is in a recently published scientific report from the U.S. Geological Survey and the National Park Service.

This study of mercury in fish is the first of its kind to incorporate information from remote places at 21 national parks in 10 western states, including Alaska. Western parks were selected for this study because of the significant role that atmospheric mercury deposition plays in remote places, and the lack of broad-scale assessments on mercury in fish in remote areas of the west.

Mercury concentrations in fish sampled from these parks were generally low, but were elevated in some instances. The study examines total mercury in fish, of which 95 percent is in the form of methylmercury, the most dangerous form to human and wildlife health.

Mercury is harmful to human and wildlife health, and is among the most widespread contaminants in the world. It is distributed at a global scale from natural sources, such as volcanic eruptions (responsible for approximately half of atmospheric mercury emissions), emissions from the ocean, and forest fires, and from human sources such as burning fossil fuels in power plants, gold mining, and incineration of municipal and medical waste. Mercury is also distributed at local or regional scales as a result of current and historic mining activities. These human activities have increased levels of atmospheric mercury at least three fold during the past 150 years.

Between 2008 and 2012, NPS resource managers collected more than 1,400 fish from 86 lakes and rivers, and USGS scientists measured mercury concentrations in fish muscle tissue. The authors found that mercury levels varied greatly, both between parks and among sites within each park. In most parks, mercury concentrations in fish were moderate to low. In fact, mercury concentrations were below EPA’s fish tissue criterion for safe human consumption in 96 percent of the sport fish sampled.

However, the average concentration of mercury in sport fish from two sites in Wrangell-St. Elias and Lake Clark (Alaska) national parks exceeded EPA’s human health criterion. Additionally, mercury levels in individual sport fish at some sites from Lassen Volcanic (California), Mount Rainer (Washington), Rocky Mountain (Colorado), Yellowstone (Wyoming), and Yosemite (California) national parks also exceeded the human health criterion.

The National Park Service is currently coordinating with state officials regarding potential fish consumption advisories. Exposure to high levels of mercury in humans may cause damage to the brain, kidneys, and the developing fetus. Pregnant women and young children are particularly sensitive to the effects of mercury.

Mercury at elevated levels can also impact wildlife resulting in reduced foraging efficiency, survival, and reproductive success. Mercury concentrations exceeded the most conservative fish toxicity benchmark at 15 percent of all sites, and the most sensitive health benchmark for fish-eating birds at 52 percent of all sites.

For more information and to view the report, please click here.



Jeff
Hiking in Glacier National Park

Montana Angler Dies In Yellowstone River

A 73-year-old man from southwest Montana died yesterday in Yellowstone National Park after losing his footing while fishing.

The man was fishing in the Yellowstone River near the Nez Perce picnic ground in the Mud Volcano area when witnesses say he lost his footing in chest-deep water while attempting to cross the river and was carried approximately 200 yards downstream in the swift current.

Another visitor ran downstream and pulled the unconscious man ashore and initiated CPR. Park rangers and medical staff were notified and responded but were unable to revive the victim.

The cause of death remains under investigation, and his name is being withheld pending completion of notification of family members.


Jeff
Hiking in Glacier.com

Yellowstone To Implement Fishing Closures Today

Yellowstone National Park is planning to implement some temporary fishing closures.

The following waterways will be closed to all fishing, effective today:

• Gibbon River below Gibbon Falls
• Firehole River below Keppler Cascades
• Madison River

Hot air temperatures, limited rainfall, runoff from thermal features, and below average stream flows have all resulted in high water temperatures in these rivers.

Water temperatures in the Gibbon River have been above 73 degrees most of the past two weeks, with water temperatures in the Firehole River above 78 degrees temperature.

Water temperatures this warm can be stressful and even fatal for trout.

Yellowstone National Park staff will continue to monitor water temperatures and stream flows in these and other rivers and streams throughout the park.

The extended forecast calls for continued hot and dry conditions with a slight chance of isolated afternoon thunderstorms. These conditions contribute to continued low stream flows and high water temperatures, and could result in additional fishing restrictions.





Jeff
Hikes in Glacier National Park