Prestile Stream, which runs through eastern Aroostook County into Canada, once was known as one of Maine’s best trout fishing streams. But during the 1950s and 1960s it became better known for its polluted waters that got so bad one Canadian town built an earthen dam to keep out the pollution.
The source of much of the pollution came as far upstream as Easton, in an area home to a number of starch factories and potato processing plants. Politicians in at least one case lowered pollution standards for the Prestile to accommodate a business. When it came to “jobs and pickerel,” it was either-or — and pickerel were on the losing end.
“[The Prestile] was one of the most polluted streams in Maine,” Nick Archer, northern Maine regional office director for the Maine Department of Environmental Protection, said. “It looks a lot better [today].”
A change in attitude and an end of dumping waste in the Prestile and other waterways have led to its recovery, Archer said. Still, the Prestile struggles to recover from a legacy of industrial and agricultural pollution.
A polluted past
For much of the second half of the 20th century, the Prestile served as little more than a dump for industrial waste from Aroostook County starch factories. At the center of what conservationists came to call “ that mess on the Prestile” was determined industrialist Fred Vahlsing Jr.
Vahlsing’s Easton potato plant was identified in the early 1960s as a major Prestile polluter, despite the owner’s assurances he would treat discharges to conform with the stream’s pollution standard. The state’s Water Improvement Commission, however, determined Vahlsing did not provide adequate treatment and noted 31 violations in 1965.
That’s also the year when Vahlsing sought a change in the Prestile’s classification to accommodate a sugar beet refinery he planned to build next to his potato plant. Many were concerned that downgrading the Prestile’s pollution standard would make the stream little more than an “open sewer.”
But supporters of a temporary downgrade included Democratic Sen. Edmund Muskie of Maine, a friend of Vahlsing known widely today for his work on the federal Clean Air and Clean Water acts. In letters to the editor in 1965, he urged the Legislature to downgrade the Prestile. Without the change, he argued, the sugar beet refinery would not get off the ground and Maine would lose the support the federal government was offering to start the industry. Maine’s Legislature followed suit and downgraded the Prestile.
And the pollution continued. The movement to clean up the Prestile had its watershed moment in July 1968, when residents of Centreville, New Brunswick, tired of pollution washing down from Easton causing routine fish kills, built an earthen dam to stem the flow of the dirty water.
The protest propelled the polluted Prestile into the national spotlight, and the later failure of the sugar beet refinery raised questions about whether downgrading the Prestile had been necessary. Formerly ardent defenders of Vahlsing, including Muskie, began to distance themselves from the industrialist and took a firm stance on promoting clean water.
A dirty legacy
Since the implementation of the Clean Water Act, the Prestile Stream stopped serving as a dumping ground for industrial and agricultural waste. Yet, from its headwater at the Christina Reservoir down to the dam in Mars Hill, the Prestile remains on the Maine Department of Environmental Protection’s list of polluted waterways.
The Christina Reservoir, which Vahlsing built in the mid-1960s to store and treat waste and serve as a water source for his potato plant, continues to be a source of pollutants that mar the Prestile. Today the Christina has a high concentration of phosphorous and nitrogen in the ground beneath it.
Runoff from nearby agricultural operations also contributes high levels of phosphorus and nitrogen.
A buildup of phosphorus, a key fertilizer component, contributes to the growth of plants, such as algae, in the stream, according to DEP environmental specialist Kathy Hoppe. These plants cause “huge” swings in the water’s oxygen levels, she said. During the day, when the sun shines on the water, the algae and other plants produce a lot of oxygen. But at night, the plants use up the water’s oxygen, stressing fish and other aquatic life.
It’s not clear how long it will take for the Christina to be cleansed of the nutrients that have caused algae blooms in the reservoir and diminished water quality downstream, but it likely won’t be for some time.
In 2007, brook trout caught in the Prestile in Mars Hill tested positive for DDT. As a result, the state toxicologist recommends Mainers eat no more than one fish meal per month from the Prestile — half the amount deemed safe to eat from the Penobscot River south of Lincoln.
Even though the insecticide was banned in 1972, state biologists continue to detect it in waterways across Maine. DDT can persist in the environment for decades. It’s hard to say how long it will take for the Prestile to become DDT free, DEP biologist Barry Mower said.
Getting better
For Archer and others, cleaning up the Prestile is a work in progress. The stream’s classification, which in essence sets the pollution standard the stream must meet, has been upgraded twice since the stream’s days as an industrial and agricultural dumping ground.
Even though the stream’s classification has been upgraded, it still fails to meet the state’s water quality standards. The classification serves as a goal, Archer said, adding, “it’s come a long way.”
Over the years the state has led several projects to improve water quality in the Prestile. In 2012, the Central Aroostook Soil & Water Conservation District led a project to plant what are known as riparian buffers near the Prestile’s banks to prevent erosion. The group also helped plant a cover crop on fields left bare after the potato harvest to retain nutrients in the soil usually lost because of runoff from rain or snowmelt. The district is continuing its efforts this year.
Such efforts have been successful in rehabilitating other Maine waterways, but it might be a while before they help to fully rehabilitate the Prestile so it can meet the state’s water quality standard.
The saga of Prestile Stream offers an invaluable lesson, Archer said: “What we do today can stay with us for a long time.”