Saving the sound: the northeast's vital estuary is in recovery.

On a side street in Norwalk, Connecticut, just a block from fully rigged sailboats bobbing in the harbor, Soundkeeper Terry Backer pulled back the grill on a storm drain and revealed a mesh box hanging from four straps and sagging under the weight of grayish sand. "All of this sediment is contaminated;" he says. "If you were producing it out of a factory, it'd have to be classified as controlled waste." The 275 Abtech filters Backer helped install in Norwalk in 2005 have collected more than seven tons of sedimentary waste, a polluted cocktail of trash, heavy metals, oil, grease, paint and, according to Backer, "whatever falls on the ground." Much of it would otherwise have ended up in the water.

Backer founded Soundkeeper, a 20-year-old legal advocacy group dedicated to protecting the environmental well being of Long Island Sound, a celebrated estuary stretching from New London, Connecticut and Long Island to New York City. Its shores are home to nine million people and its watershed stretches 17,000 square miles from suburban Westchester County, New York to Canada. The "airshed" that affects its water quality includes the Ohio Valley, with its phalanx of coal-burning power plants.

Long Island Sound is only 110 miles long, but its health is an issue with national, even international, scope. Backer's efforts are part of the long and difficult campaign to end the near-fatal pollution of this oft-beleaguered waterway. "It's cleaned up in many ways;" he says, "but the history of the population around it has caused layers of issues. We pull back one layer and find many layers to go."

The current layer under study is nitrogen pollution. It contributes to such problems as hypoxia, a dissolved oxygen deficiency that impedes the survival and reproduction of aquatic species. The majority of the nitrogen in the Sound enters from so-called "point sources" through direct discharge: heavy industry and sewage treatment plants. But runoff from roads and storm drains--non-point source pollution--is also a significant issue.

In 1998, the states of Connecticut and New York, along with the federal Environmental Protection Agency (EPA), agreed to reduce the amount of nitrogen discharged into Long Island Sound by 58.5 percent. As of 2005, the Long Island Sound Study (LISS) reported that nitrogen discharge had fallen 25 percent, signaling both the success of regulation and the difficulty of controlling pollutants that enter the water from such diverse sources as construction sites, farms and over-fertilized lawns.

There are 108 sewage treatment plants in New York and Connecticut; 45 of those dump their end-of-pipe waste directly into the Sound. Mark Tedesco, the technical director of the EPA's Long Island Sound office, is pleased with the EPA and states' combined reduction efforts, but he's also aware that the target remains distant. "The big story is that, by and large, regulation has worked" he says. "We've had some remarkable success in addressing the problem, but the 25 percent drop in sewage load is less than halfway to our goal" he cautions.

Connecticut gives sewage treatment plants a chance to take part in an innovative plan called nitrogen trading. "Quite simply, they're allowed to meet their limit by either meeting the goals or by buying credits" says Paul Stacey of the Connecticut Department of Environmental Protection. If a plant emits less nitrogenous waste than its permit allows, it can save surplus credits for the upcoming year or sell them to less-efficient plants. Stacey estimates that Connecticut municipal treatment plants are two fifths of the way to their 58 percent reduction goal, putting them two or three years ahead of schedule.

Seventy-nine facilities participate in the nitrogen trading program, which allows the state to meet its yearly targets without upgrading every plant simultaneously, and fewer construction projects translates into lower costs. "We're probably saving $200 million on this;" Stacey says.

Success controlling non-point sources, such as wastewater runoff, has proven more elusive, largely because of the myriad ways that pollutants can enter the Sound's waters. "The easiest way to treat something is to concentrate it" says Tedesco. "The harder thing is to treat something that by its nature is diffuse. We can measure what comes out of sewage plants, but no one's measuring your septic system:"

LISS has found no progress on nitrogen discharges from non-point sources since 1991, and Eileen Keenan of the New York Sea Grant, a university-based aquatic research group, believes that the problem is actually getting worse. "We have an increase in the quantity and a decrease in the quality of the runoff;" she says.

Chemical and sediment runoff, both from farms and construction sites, is a major culprit. Rainfall can sweep manure and pesticides off fields, and the chemicals then enter the groundwater and flow towards the Sound. Wetlands can lessen the load by soaking up excess nutrients including nitrogen. But according to LISS, Connecticut wetlands have shrunk by approximately 1,900 acres since 1990. Runoff from construction sites is a particularly pressing problem in Connecticut, where an eight percent increase in the population has led to a 15 percent increase in development. "We're building out, not up," warns Tedesco, "and that has consequences for run-off into Long Island Sound;"

Unfortunately, runoff pollution continues long after construction (see cover story this issue). Development creates impervious surfaces that increase both the volume and the velocity of runoff. Instead of sinking into the ground, water runs over roads, rooftops and parking lots. It whisks away fuel spilt in gas stations, excess fertilizer from over-treated lawns, trash and pet feces from the streets, and funnels all of it into the stormwater system. There have even been a few homeowners who, lacking a firm grasp on the intricacies of indoor plumbing, have piped their toilets directly into storm sewers.

Paul Stacey believes that, while his state organization has reduced nitrogen loads from treatment plants, the burden of success on non-point sources lies rise-where. "The more we look the more we see that it's really the individual homes that are the main source of the pollutants" he says.

But getting people motivated is difficult. "There are people who live in the Long Island Sound watershed who feel disconnected from it," says Tedesco. He further claims that 16 to 20 percent of the nitrogen in Long Island Sound comes from rain that falls on the estuary itself or enters the watershed. Stacey says that airborne pollution from Midwestern power plants contributes to the problem. In 1997, Connecticut Attorney General Richard Blumenthal petitioned the EPA to reduce pollution from Midwestern plants, and, after eight years of litigation, Ohio Edison has agreed to dramatically reduce power plant emissions and pay Connecticut $1.1 million.

Despite the challenges, Terry Backer's view from the Soundkeeper office, perched across the road from the local oyster fleet, remains optimistic. "I think I do see sunshine" he says, but "anything we do here has to be sustained, or it's just a respite:"

CONTACT: Long Island Soundkeeper, (800)933-SOUND, www.soundkeeper.org; Long Island Sound Study, [phone], www.longislandsoundstudy.net; Save the Sound, [phone], www.savethesound.org; Soundwaters, [phone], www.soundwaters.org.