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Long Island’s Elephant in the Room: Nitrogen Pollution

April 24, 2013

Research is clear: People care deeply about clean water, but often don't know where it comes from. Photo: Giuseppe Saitta

By Marci Bortman, director of conservation programs, The Nature Conservancy in Long Island

“How about we initiate a ‘poop at work’ campaign?”

My colleague Carl was kidding about how to improve water quality on Long Island, but his joke went right to the heart of the problem. Many Long Island residents commute to New York City for work every day. Carl’s idea would solve the problem that we are grappling with on Long Island, as are many estuaries around the world: There is too much nitrogen in coastal waters and much of it is coming from inadequately treated human waste.

Social science research the Conservancy has carried out tells us that the average person living on Long Island cares deeply about clean water, whether it is to swim or fish in, or live near, or it is clean, freshwater we drink. Our social science research also tells us that the average Long Islander does not know:

  • where their drinking water comes from (answer: groundwater);
  • where their waste goes when they flush the toilet (answer: mostly septic systems, which are not designed to remove nitrogen, or sewage treatment plants in the more urbanized areas); and
  • that nitrogen from human waste, fertilizer and burning fossil fuels are polluting Long Island bays and harbors.

And if we do not tackle nitrogen and nutrient pollution on Long Island, our work could fail.

The Conservancy on Long Island has a long-standing marine program focused on estuarine restoration and coastal climate change resilience and adaptation. And by many counts we have been successful. We re-directed land acquisition to better protect estuaries. We acquired 13,500 acres of underwater land and transplanted over 7 million clams in over 100 sanctuaries. We supported science and policy to protect and restore seagrass, and we developed a network of monitoring sites to determine whether salt marshes are keeping pace with sea level rise.

Yet the ultimate success of all these projects hinges on nitrogen: Excessive nitrogen loading will impede our efforts over the long-term.

Why? Because regardless of the millions of hard clams returned to Great South Bay, it suffers from harmful algal blooms hampering the growth and adequate recruitment of bivalves. Regardless of the availability of land to which salt marsh can migrate, excessive nitrogen loading is a key driver of marsh loss. Regardless of successful passage of legislation we crafted to protect seagrass, science has found that impacts from excessive nitrogen and warming sea temperatures together inhibit seagrass growth and expansion even when physical impacts are limited.

“The Largest Pollution Problem in the Nation’s Coastal Waters”

None of these findings are unique to Long Island. Howarth and Marino (2006) contend, “Today there is a scientific consensus, which has emerged from research at several spatial and temporal scales, that nitrogen represents the largest pollution problem in the nation’s coastal waters and one of the greatest threats to the ecological functioning of these ecosystems.”

There is also scientific consensus that harmful algal blooms (HABs) are fueled by nutrient pollution and improved management of inputs can lead to significant reductions. These HABs are expanding globally, are lasting longer, and have increasingly higher toxicity. There have been reported deaths from eating shellfish tainted from red tide HABs — not only are finfish and manatees dying, but people too are at risk from paralytic shellfish poisoning and other serious illnesses related to ingesting and sometimes even breathing in the toxins. Excessive nitrogen is also linked to acidification in freshwater and marine surface waters. In the groundwater  — which is the sole source of drinking water on Long Island, and the primary source of freshwater to Long Island estuaries — nitrogen levels in some areas are the same as levels correlated with colon cancer, bladder cancer and non-Hodgkins lymphoma. Yet levels are below the federal safe drinking water standard.

Directly addressing nitrogen pollution and its underlying causes is arguably one of the biggest challenges The Nature Conservancy has ever faced on Long Island, largely because of the magnitude of the problem and the public expense of the solutions. For example, in Suffolk County (approximately half of the Long Island population), there are over 400,000 cesspools and septic systems in place — waste treatment technology that is not designed to reduce nitrogen from the waste stream. Rather, nitrogen steadily seeps into groundwater and surface water. A proposal being considered to expand and build new sewage treatment plants to serve only six small areas on Long Island is estimated to cost over $2 billion.

Like other coastal communities, Long Island is also facing the problem that as sea levels rise, there is a corresponding rise in the water table. Current estimates indicate that along the coast, over 15,000 septic systems are currently in areas where the water table is less than five feet deep. Future scenarios predict higher than average sea level rise. And, super storm Sandy, which may or may not be a harbinger of more frequent, extreme storms, resulted in the devastation of a sewage treatment plant that serves over half a million people on Long Island. For months over 50 million gallons per day of raw and partially treated sewage discharged into a bay already suffering from eutrophication

The Problem – and Solutions – Are Varied

Problems with nutrient loading are not limited to coastal locations; they present serious threats to freshwater and marine ecosystems throughout the world.

Across the globe, scientists are documenting widespread hypoxia and anoxia, habitat degradation, alteration of food-web structure, loss of biodiversity, and increased frequency, spatial extent, and duration of harmful algal blooms in coastal systems.

Unlike Long Island, much of the nitrogen that causes these problems throughout the world is transported via rivers. In some areas like the Gulf of Mexico, 70% of nitrogen and other nutrients are from agricultural runoff into the Mississippi River. In other areas, such as the Massachusetts Islands, nitrogen sources impacting seagrass are primarily from atmospheric deposition. In the coastal waters of South America, Asia and Africa, urban wastewater is the primary source of nutrients.

The problem is varied and complex and the solutions are, too — the solutions will be at various levels including local. On Long Island, this means we must:

  • become experts (or seek expertise) in the Clean Water Act and pursue ways to amend state and local laws to strengthen groundwater and surface water protection;
  • investigate new and innovative technologies to better treat human waste;
  • find creative financing strategies to bring sufficient public funds to lower the cost of replacing antiquated waste treatment infrastructure with 21st century solutions;
  • find ways to use social science to communicate the problem and sense of urgency, and understand costs and benefits to compel action by decision makers; and
  • work with partners by building coalitions with other environmental non-governmental organizations, health advocates, businesses, and opinion leaders.


Problems like nutrient loading also affect freshwater systems around the world, like this Illinois River that supplies drinking water for thousands of people. Photo: Matt Miller/TNC
Problems like nutrient loading also affect freshwater systems around the world, like this Illinois River that supplies drinking water for thousands of people. Photo: Matt Miller/TNC

Editor’s Note: This piece originally ran, in slightly different form, in The Nature Conservancy’s Science Chronicles. 


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Opinions expressed on Cool Green Science and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy.

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