To reach Lake 658, you leave the Trans-Canada Highway in the moose-ridden backwoods of western Ontario, creep down a teeth-jarring gravel road, follow a trail to a different lake, hop onto a motorboat and then take a short hike to 658’s granite shoreline. The water is crystal-clear, and yet a sign warns: “Attention — Fishing is Prohibited in the Lake.” This area is far from any source of industrial pollution, but angling would disrupt an unusual long-running study of pollution.

For years, scientists deliberately contaminated Lake 658 with toxic mercury to track its travels through the ecosystem. Lake 658 is part of the Experimental Lakes Area, or ELA, an open-air laboratory that includes 57 other small lakes. Started in 1968, and run by a Canadian federal agency, the Department of Fisheries and Oceans Canada, the ELA is also used by U.S. scientists. And ELA research has helped shape U.S. federal environmental laws as well as Western state and county regulations.

The experiments are bold adn unusual, because they have to be: You can’t stuff an entire lake into a test tube. From 1969 to 1976, researchers added combinations of nitrogen, phosphorous and other nutrients to seven lakes, and verified that phosphorus causes algae blooms and biodiversity loss. That knowledge persuaded policy-makers to phase out phosphates in laundry detergents, and helped spur legislatures in states such as Montana, Utah, Washington and Oregon to limit phosphates in dishwasher detergents. It also aided grassroots campaigns discouraging the use of phosphorus lawn fertilizers around Montana’s Flathead Lake and California’s Lake Tahoe.

From the 1970s to the 1990s, ELA researchers conducted “the first whole-ecosystem” study of acid rain by adding sulfur to lakes. Their discovery that even small shifts in acidification kill fish led Congress to pass the 1990 Clean Air Act amendments, which established a regula- tory system for reducing sulfur emissions from coal-fired power plants. The ELA has also been used to study hormone- disruptors, like the synthetic estrogen in birth-control pills, which ends up in rivers and lakes.

When U.S. Environmental Protection Agency researchers grew concerned about mercury emissions from coal plants, the ELA was the only place they could add a potent neurotoxin to an entire lake. […]

This article was reported in partnership with The Investigative Fund at The Nation Institute, now known as Type Investigations.

To read the rest of this article, please pick up the December 24, 2012, issue of High Country News.