Page 2 of 4
An icy dam blocked the Clark Fork River as it entered Idaho from Montana more than 10,000 years ago. Behind the dam to the southeast lay Glacial Lake Missoula. Two thousand feet deep, it sprawled out over 200 miles, from Deer Lodge to Seeley Lake and from Libby to Darby. The dam melted and froze in cycles, sending floods carrying massive ice chunks and boulders that cut deep grooves in the earth for miles around.
Missoula Water Quality District Director Peter Nielsen has dedicated much of his life to water. He was the executive director of the Clark Fork Coalition before signing on to the City-County Health Department 20 years ago. Typically subdued, his voice quickens when he talks about Glacial Lake Missoula. "It created the geography of western Montana," he says.
Flood-and-fill cycles shaped the stepped tiers that ring Mount Jumbo today, reflecting Glacial Lake Missoula's former shorelines. Boulders, cobble, and gravel carried in the floods carved out lands to the west, all the way to Oregon's Columbia River Gorge. Over time, they settled, forming a massive underground storage tank that's now topped by porous soil: the Missoula Aquifer.
The aquifer is the valley's primary water source. Rain and snow feed it via runoff from the Clark Fork River. In some places, groundwater that runs through the aquifer touches the surface. Such intimate proximity means Missoula's water supply is extremely vulnerable. "The Missoula Aquifer is our lifeblood," Nielsen says. "It is really the only reliable source of water we have. And we live on top of it."
Over the years, Missoula's water supply has been tainted in places. The worst crisis was—and to a certain extent, remains—arsenic contamination at Milltown Dam, at the aquifer's mouth. For more than 100 years, mining and milling wastes from Anaconda and Butte were released into the upper Clark Fork. The sludge, contaminated with arsenic and heavy metals, accumulated behind the Milltown Dam. Reservoir sediments were releasing 105 pounds of arsenic per day into the Missoula Aquifer when Missoula County health officials detected the contamination, in 1981. Levels in wells at Milltown ranged from 220 to 510 parts of arsenic per billion. The federal drinking water standard for arsenic is 10 parts per billion.
Even today, some 150 years after mining operations began in Butte, almost 30 years after the reservoir was declared a Superfund site, and not quite two years after the last sediments were hauled off in trains, wells near the reservoir are contaminated with arsenic, a carcinogen. "It's known to cause five or six different types of cancer," Nielsen says. "And not just in lab rats—in humans."
Mining is part of Montana's past. It could also be in the state's future. Meanwhile, Montanans are taking more drugs, and more complex drugs, than ever before. Samples taken from the Clark Fork River show caffeine, anti-seizure medications, and cholesterol drugs. "They're in the river, they're also in the ground water," says Jon Harvala, an environmental health specialist for the Missoula City-County Health Department.
"We as a people ingest a lot of chemical compounds," Harvala says. "Perhaps we ought to be more careful about what we ingest. That's the real issue—we're a pharmaceutical nation."
Nielsen concurs. "I can't blame Exxon or something for it," he says. "It's something that I did. It's really not the wastewater plant that's the source, it's us."
'The average citizen probably doesn't know'
Sharp peaks, whispering waterfalls, and tall pines surround the Hyalite Reservoir, an 8,000-acre-foot body of water in the Gallatin National Forest. This is where Bozeman's water comes from. It's piped from the reservoir to the Sourdough Water Treatment Plant, where millions of gallons daily are filtered and chlorinated before they're sent to Bozeman consumers. Montana Bureau of Mines and Geology hydrologist Gary Icopini is finishing up a two-year study, like Lynch's work in Missoula, aiming to gauge the resiliency of manmade chemicals in Bozeman's water supply.
Icopini's findings are strikingly similar to Lynch's. He tested 28 water supply wells located across Bozeman. Sulfamethoxazole showed up in 11. Four wells contained the anti-seizure medication carbamazipine. The active ingredient in Prozac popped up in five wells.
"Those three chemicals are highly recalcitrant," Icopini says. "They stick around a long time."
Icopini and Lynch's research reflects findings in Helena. In 2005, the Montana Bureau of Mines & Geology and the state Department of Environmental Quality tested 35 domestic wells serving the Helena valley. They uncovered a chemical cocktail of 22 compounds including antibiotics, painkillers, and anti-inflammatory and seizure-control drugs, along with anti-depressants, estrogens, and androgens (which are typically considered a male hormone, though they're also naturally present in women). As with the Missoula study, researchers found small amounts of caffeine, plasticizers, insect repellent, and herbicide.
With fewer people to worry about, Montana water managers have less pharmaceutical waste to manage than their counterparts in larger urban populations. But according to a study completed in 2000 by the U.S. Geological Survey (USGS) that tested for 95 chemicals in 139 streams downstream from urbanized areas or livestock operations in 30 states, one or more chemicals were detected in 80 percent of the streams. Eighty-two of the 95 chemicals tested for showed up at least once. As the USGS findings indicate, wells positioned at lower elevations from wastewater treatment plants are especially vulnerable, even in Montana.