Six-year study says parks have chemicals in snow, fish and trees

By Laura Snider of The Daily Camera 

issued Thursday, February 28, 2008

A study six years in the making reports that heavy metals and pesticides can be found in the water, plants and animals of 20 national parks -- including Rocky Mountain National Park -- that span the West from Alaska to the Mexican border.

"It was somewhat surprising to find that even the most remote and celebrated pristine places are affected," said Colleen Flanagan, a Park Service ecologist based in Denver.  "It's a testament that what goes up does, indeed, come down."

At least 70 different contaminants have settled out of the air over the country's national parks, some blown in from as far away as Asia and others from nearby industries and agricultural lands. The six most-worrisome chemicals, because of their long-lived persistence in nature and their current concentrations, are mercury; the three pesticides DDT, dieldrin and chlordane; PCBs, which are used in fire-retardant materials; and PAHs, a byproduct of industrial combustion.

The study does not recommend specific policy changes or actions. Instead, the data-rich research provides parks with a baseline of information that individual parks can use to direct future research.

Scientists took samples of air, snow, water, lake sediments, lichens, conifer needles and fish in Rocky Mountain National Park and seven other “core” parks.

In Rocky Mountain National Park, the level of dieldrin found in three of 20 fish exceeded the allowed concentrations for human consumption. The amount of mercury found in fish was relatively low but still exceeded the concentrations recommended for otter, mink or kingfisher, all of which depend on the fish for food.

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                       Likely mercury-laden snow below Emerald Lake in Rocky Mountain National Park

Mercury in the snow, on the other hand, was relatively high. Also, about 7 percent of the fish tested had intersex characteristics, meaning sperm and eggs were found in the same fish.

The other seven core parks were Noatak National Preserve, Gates of the Arctic National Park, Denali National Park, Olympic National Park, Mount Rainier National Park, Glacier National Park and Sequoia and Kings Canyon National Park.

Scientists tested the trees, lakes, fish and snow in eight Western national parks for more than 100 chemicals and found 70 of them present at measurable concentrations. Six are cause for the most concern:

1.  Mercury is spewed into the air from coal-fired power plants. When humans are exposed to mercury, it can impair neurological development in fetuses, infants and children.

2.  Dieldrin is a pesticide that was used on citrus, corn and cotton crops. It was also used as a wood preservative and to control termites. Dieldrin, which was banned from most uses in 1987, suppresses the immune system and decreases reproductive success.

3.  DDT was a pesticide used until it was banned in 1972. The chemical is a probable human carcinogen, and it decreases reproductive success among birds.

4.  PCBs were used as hydraulic fluids, adhesives and fire retardants. Most uses were banned in 1979. PCBs damage the liver and can cause cancer.

5.  PAHs are combustion byproducts formed by industrial processes, wildfire, vehicles and even grilling meat. The chemical can cause reproductive side effects.

6.  Chlordane was an insecticide used on corn, citrus and vegetables until it was banned in 1988. The chemical also damages the liver and can cause cancer.

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