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Pollution’s Long Commute

Pollution’s Long Commute header image
New study reveals contamination in the world’s most remote places.

No matter how high you climb up the mountains or how far north you travel into the Arctic, no matter how remote you find yourself, you will find some of the world's most toxic chemicals in concentrations that threaten fish and humans.

"Places that are far removed from human activity, places high in altitude or high in latitude, were once thought to be pristine," said Carl Schreck. "They are not; nothing is pristine anymore. Pollution doesn't go away, because there is no 'away'."

Mules and horse photo by Carl Schreck.

The scientists used horses, where they could, to pack in more than a ton of research equipment to high wilderness lakes. Photo: Carl Schreck

Schreck, a professor in OSU's Department of Fisheries and Wildlife, is part of a collaboration of university and government scientists who have recently completed a six-year study of airborne contamination in national parks from California to Alaska. The National Park Service first became interested in the issue of airborne transport of contaminants when they found compounds such as DDT and PCBs in arctic parks, far from any agricultural or industrial source. The Western Airborne Contaminant Assessment Program (WACAP) was commissioned to learn more about the pollutants found in these remote areas, where they came from, and how they impact the plants there.

WACAP camp photo courtesy National Park Service.

The WACAP researchers found evidence of industrial pollution as far north as the Arctic Circle, thousands of miles from industrial centers. Photo courtesy National Park Service.

Far from the usual crowds of national park visitors, the researchers trekked to isolated wilderness lakes in the high Sierra, Rocky, and Cascade mountains, and deep into Alaska's backcountry. There, they measured toxic metals and other contaminants in snow, soil, air, water, fish, and vegetation in places once thought to be among the most pristine areas in the world.

Some of these contaminants have a very long commute, crossing the Pacific Ocean on atmospheric currents from as far away as Asia and eastern Europe. These air masses can carry coal smoke (a major source of mercury) and polychlorinated biphenyls (PCBs) emitted from industrial sites in Russia, China, and elsewhere. Some concentrate in cold environments, where they settle on soil, vegetation, and water. Mercury, PCBs, and pesticide compounds can be rained down into arctic lakes, bound onto falling snowflakes, or absorbed from the air by vegetation.

China photo by Dave King.

The world’s pollution migrates around the globe, hitchhiking on global air masses into the highest altitudes and polar latitudes. Photo: Dave King

Staci Simonich is an expert in tracking airborne pollutants in global air currents. A professor in OSU's Department of Environmental and Molecular Toxicology, she leads the project's assessment of persistent organic pollutants. "These compounds can travel very long distances in the atmosphere," Simonich explained. When air masses hit the mountains of western North America, some of the pollutants they carry begin to fall out. As contaminants are deposited, they warm, volatilize, and rise farther up the mountainside before they settle, volatilize, and rise again. In this way, persistent organic pollutants hopscotch their way into the highest elevations and latitudes.

It takes more than hopscotch to get a team of scientists and all their research gear into these remote areas. They carried the bare essentials: 2,000 pounds of scientific equipment, inflatable boats, hand pumps, dry ice, shelter, and food for eight people for three or four days. Where pack animals were allowed, they used horses to help carry the load. In remote arctic lakes, they relied on floatplanes to reach their sampling sites.

snow measurement photo courtesy National Park Service.

In winter, the researchers collected snow samples throughout the depth of the snowpack and packed the samples out on skis and sleds. Photo courtesy National Park Service.

"A floatplane would drop us off with all our equipment a hundred miles from the nearest village," said Adam Schwindt, one of the OSU researchers with the WACAP team who worked in the arctic parks. "We just hoped that the weather would hold for three or four days so the plane could come back to get us when we were done."

"Bears were a big concern," said Schreck, who leads the USGS Cooperative Fish and Wildlife Research Unit in Oregon and led WACAP's fish physiology investigations. "Almost everywhere we sampled, there were bears. And there we were, dissecting fish, covered in fish blood, in a camp filled with fish samples."

And there was the fatigue factor. The researchers had to carry everything in, sometimes on their backs, set up camp at 10,000-foot elevations, then work very precisely for 16-hour days. They devised hand-powered portable gadgets to accomplish tasks usually reserved for bigger, heavier, more sophisticated instrumentation. They rigged a hand-cranked centrifuge resembling an old washing machine and packed in hundreds of pounds of dry ice to freeze their samples for later analysis.

WACAP researcher photo courtesy National Park Service.

The effects of airborne contaminants on these pristine areas are not immediately visible. But the evidence accumulates in sediments, vegetation, and in the tissues of fish. The mercury levels of fish sampled from arctic lakes were found to exceed safety levels for human consumption. Photo: National Park Service

Using an inflatable raft, a winch, and some aircraft cable, the researchers probed layers of lake sediments. The layers could be read like a history book written through more than 130 years. There were layers of fly ash from early coal-fired plants, cleaner sediments that marked the passage of the Clean Air Act, and recent increases in contaminants that likely marked the Asian industrial boom. Pesticides, both those in current use and those long-banned, showed up in the high lakes of Rocky Mountain, Glacier, and Sequoia national parks.

Many of the contaminants end up in fatty tissues of fish and can accumulate as contaminated fish are eaten by other fish in turn. Such bioaccumulation has caused some fish to exceed the safety threshold for food, a concern for people who live off those fish in arctic communities, Schreck explained.

centrifuge photo courtesy National Park Service.

Battling mosquitos and wary of bears, the WACAP researchers developed portable lab equipment, such as this hand-powered centrifuge, that could be carried to remote locations and operated without auxiliary power. Photo: National Park Service

The researchers observed endocrine disruptions that feminized male fish, a trait sometimes found in fish in sewage treatment plants. "We have seen physiological and pathological changes in fish in these lakes and an accumulation of toxic chemicals in the environment that could only have come by air," said Michael Kent, director of the center for salmon disease research at OSU and head of the WACAP fish pathology investigation.

Airborne contaminants are absorbed by some kinds of vegetation, and the researchers found contaminants accumulated in lichen and in the needles of trees. When the needles dropped they carried an application of chemicals to the ground with them. In this way, and in many other ways, toxic metals and organic compounds persist long after being released into the atmosphere.

In the winter, the researchers carried their gear on skis and sleds to sample the snowpack. They tunneled down as much as 15 feet into the snow to measure its temperature, density, and other characteristics. They packed samples of snow into dozens of containers the size of basketballs and hauled them back to camp on sleds and in backpacks. Then they shipped the frozen samples to Simonich's lab at OSU, where her team tested for the presence of 89 different organic compounds and 49 toxic metals.

Stacy Simonich photo by Peg Herring.

OSU environmental toxicologist Staci Simonich (above) oversaw the analysis of 600 samples of snow, vegetation, sediments, and fish collected during three years of field sampling in western national parks. Photo: Peg Herring

"We had to keep the snow frozen until we were ready for the analysis, because snow chemistry can change as it melts," Simonich explained. Some of the targeted compounds can turn to gas and escape as the snow melts, so it took Simonich's team about six days to melt and filter each snow sample and test it for hazardous compounds.

It took them even longer to develop the laboratory procedures they would use to test the samples, tests that they would be the first to develop and use. "The students in my lab were working 24/7, each specializing in one type of test," she said "The results were phenomenal: two PhD's and two master's degrees based on new procedures developed during this project."

WACAP Researchers photo by Carl Schreck.

Student researchers Luke Ackerman and Jennifer Ramsay joined OSU fisheries biologist Carl Schreck (right) in a makeshift field laboratory where they prepared tissue cultures for transporting back to OSU where toxicologists performed a battery of tests to identify precise levels of contamination. Photo: Carl Schreck

The strength of the study comes in part from the collaboration among agencies and across disciplines, according to Dixon Landers, the project's scientific director and a senior research scientist at U.S. Environmental Protection Agency.

"We had no idea what suite of contaminants we would find or where we'd find them," Landers said. "We were investigating the presence of more than 100 compounds across a very large area, essentially from the Arctic to Mexico." Some sources of pollution were nearby and obvious: smelters, industrial agriculture, population centers. Others were much more distant. Still others were the result of chemicals long banned but still making their presence known. For example, DDT is so persistent, soils are still exhaling it from applications made 40 years ago.

Jennifer Ramsay, a student researcher with the WACAP team, recalled a moment working at a site above the Arctic Circle. "A herd of caribou came up and just stared at us; they probably had never seen a human before," she said. "It's hard to imagine that you can be so far away from the industrial world and still measure its impact."

WACAP - Western Airborne Contaminants Assessment Project

Published in: Ecosystems