Long Island Sound Water Quality Has Improved; Challenges Still Ahead

STAMFORD — A new report on the health of Long Island Sound by the Long Island Sound Study (LISS) tracks for the first time the water quality of the sound by its three distinct basins. The report shows that while progress is being made to clean up the sound, there are still challenges ahead to restore and protect this valuable resource.

Sound Health 2006: A Report on Status and Trends in the Health of the Long Island Sound includes a water quality index that shows, on average, water quality in the sound was good 54.3 percent of the time and fair 41.2 percent of the time between 1991 and 2004. As expected, the western basin, with its densely developed shoreline, is the most stressed, with fair water quality the majority of the time. Water quality improves in the central basin, and in the eastern basin water quality is good 86 percent of the time.

The water quality index, developed by the EPA Office of Research and Development for the National Coastal Assessment, includes five measures of water quality: dissolved oxygen levels, the amount of chlorophyll A (an indicator of planktonic algae), water clarity, and concentrations of two nutrients, nitrogen and phosphorous. These measures were evaluated from May to October, the time of year when pollution has the greatest effect on water quality.

The 16-page report also highlights progress made in a number of areas since a Comprehensive Conservation and Management Plan was developed by the Long Island Sound Study in 1994:

First, sewage treatment upgrades have resulted in 47,000 fewer pounds of nitrogen a day entering the sound since the peak year of 1994. Over the past three years, however, nitrogen discharges increased by about 8,000 pounds a day in the sound, mainly as a result of nitrogen treatment being suspended while upgrades are under construction. Overenrichment of nitrogen fuels the excessive growth of aquatic plants (a process called eutrophication) and leads to a harmful depletion of oxygen in the sound.

Second, emissions of heavy metals and other contaminants into the atmosphere and directly into the sound and its tributaries continue to decline. As a result, concentrations of a number of contaminants in seafloor sediments have declined significantly in the past two decades.

Third, populations of certain popular fish species, such as striped bass and scup, are increasing thanks to fishery management efforts.

And finally, since 1998, federal and state efforts have opened 90.2 miles of rivers draining to Long Island Sound to anadromous fish (fish that swim up river to spawn), nearing the LISS goal of 100 miles reopened by 2008.

The report characterizes the health of the sound using more than 20 different indicators — specific, measurable markers that document trends in water quality, living resources, land use and development, and public awareness. Both sharp changes and general trends in the values of those markers can indicate improved or worsening environmental health.

This year’s report updates a report published in 2003, and is available online at LongIslandSoundStudy.net. The first issue of Sound Health was published in 2001. 

On April 23, more than 425,000 copies of the new report were made available as inserts in coastal Sunday newspapers in Connecticut and New York. An additional 40,000 copies will be distributed to schools, aquariums, nonprofit groups and citizens at their request.

To receive a free copy of Sound Health 2006, call the EPA Long Island Sound office at 203-977-1541. The full report can also be downloaded from the LISS website.