Long Island Sound water quality improves as nitrogen pollution lessens, report says

Efforts to cut the amount of nitrogen pollution released into Long Island Sound by wastewater, fertilizer, and out-of-date sewage plants and septic systems are continuing to help improve water quality, a regional nonprofit said in a report released Thursday.

The report, by the nonprofit Save the Sound of New Haven and Larchmont, found that 98% of the open waters of the Sound earned a "B" or higher grade.

The "Eastern Narrows," section got a "B," which is up from a "C" in the prior report two years ago, and up from a "D+" in 2008, when the study began.

But in what the nonprofit called "sobering news," the waters closest to New York City, the "Western Narrows," kept its "F" grade, despite some signs of improvement.

Of the 57 bays and bay segments along the Sound's shoreline, 42% got a C or worse, "in some cases even when adjacent open waters scored higher — illustrating the need for additional nitrogen and pollution reduction efforts in these waters," the report said.

The farther east one goes in the open Sound waters, the better the quality. Long Island Sound is 110 miles from east to west, from the North Fork to Hell Gate at the top of the East River.

The Eastern Narrows includes Westchester, parts of Connecticut and on Long Island, the Huntington-Northport area. The Western Narrows include city waters including the upper East River from Hell Gate up through the Throgs Neck Bridge, the Bronx-Westchester border and the Queens-Nassau border on the opposite side.

Mitigating nitrogen pollution is key to preserving and improving water quality in the Sound, experts said.

Christopher Gobler, SUNY distinguished professor at Stony Brook who is chairman of Coastal Ecology and Conservation School of Marine and Atmospheric Sciences, said "the trajectory and recovery of the main stem of Long Island Sound since the implementation of the EPA nitrogen reduction plan in 2000 is one of the great ecosystem recovery stories of North America."

The plan, put forward by the EPA with New York and Connecticut’s agreement, led to upgrades in sewage treatment plants, primarily in the New York City area.

"Nitrogen loading to Long Island Sound from New York City sewage treatment plants was cut by 60% and the low oxygen dead zone shrank from covering almost two-thirds of the Sound to now only occurring in a small region in the far west of the Sound," he said.

But, he said, the report emphasizes that in the regions in Nassau and Suffolk County where nitrogen reductions haven’t been implemented, "conditions have followed the opposite trajectory and worsened."

David Ansel, vice president of Water Protection for Save the Sound, said that clean water free of nitrogen is essential to a functioning region and health for the people who live, work and recreate there. The report shows progress, he said, but there’s more work to be done.

Nitrogen in the Sound comes from the wastewater generated by the 9 million people living in the multistate region served by the Sound — on top of those who come in for work and play.

"The nitrogen does have some risk of causing human health problems, but we know that it’s terrible for water quality generally. You don’t want to be drinking it. You don’t want it in the bays and harbors," he said.

"Nitrogen causes the water to become ecologically unhealthy and it damages the ecology of the Sound ... It becomes unstable for the marine environment and ultimately bad for people."

He noted because of pollution, the commercial fishing business isn’t as robust as it could be. For example, there are parts of the Sound where it’s not safe to eat the fish.

Among the options the nonprofit suggests: upgrading outdated wastewater infrastructure, repairing miles of underground sewer pipes and issuing grants to aid homes and businesses on the Island to replace septic systems with new ones that reduce nitrogen.

There’s a vote planned for November — Proposition Two — asking Suffolk residents to approve a 0.125% increase in county sales tax to fund an expansion of sewers and septic systems that filter nitrogen out of wastewater.

By Matthew Chayes

matthew.chayes@newsday.comchayesmatthew

Matthew Chayes, a Newsday reporter since 2007, covers New York City.