Nitrogen pollution threatens Cape Cod

HARWICH, Mass. The Massachusetts Department of Environmental Protection (DEP) has scheduled a public meeting for Aug. 26 to seek comment on a draft document identifying the need to reduce nitrogen pollution in the Cape Cod coastal waters of Allen, Saquatucket and Wychmere harbors and in the Herring River.

The public meeting will be held at 3 p.m. in Town Hall, 732 Main St.

The restoration plan for this estuary system, formulated by DEP and the University of Massachusetts at Dartmouth School for Marine Science and Technology (SMAST), is proposed as part of theMassachusetts Estuaries Project, intended to improve estuarine water quality in 70 embayments along the southeastern Massachusetts coastline.

This coastal water body system is currently impaired because of excess nutrients, mainly nitrogen, according to a SMAST study. Nitrogen is the primary cause of eutrophication, which can lead to:

Loss of eelgrass beds, which are critical habitats for fish and macro-invertebrates such as sea worms, snails and crabs.

Undesirable increases in macro algae, which are much less beneficial than eelgrass.

Periodic extreme decreases in dissolved oxygen concentrations that threaten aquatic life.

Reduced diversity in sea-bottom-dwelling species such as worms and clams.

Periodic algae blooms.

Steady population growth and increased development, particularly during the past several decades in southeastern Massachusetts, has led to an overabundance of nitrogen in Cape Cod harbors, bays and estuaries, according to the study. The primary controllable source of nitrogen is wastewater discharged from septic systems, stormwater runoff, leaching lawn fertilizers and discharges from agricultural land uses. Atmospheric deposition also contributes varying quantities of nitrogen.

At the public meeting, DEP staff will present a draft total maximum daily load (TMDL) for limiting nitrogen to the amounts that the water bodies can absorb without violating water-quality standards and impairing uses such as fishing and recreational activities. The plan calls for reducing watershed sources of nitrogen by up to 80 percent. Most of the reductions will be from better treatment and handling of wastewater, but nitrogen from stormwater and fertilizer use should also be controlled wherever possible.

This effort included three years of chemical, physical and biological studies within the Herring River and Allen, Saquatucket and Wychmere harbors. Another component was the use of a dynamic water-quality model to determine the present sources of nitrogen and the loading rates, the nitrogen concentrations in the embayment, the nitrogen concentrations that will result in the restoration and protection of the embayment, and the target nitrogen loading rates that will achieve those protective concentrations.

This watershed modeling and TMDL analysis will serve as a planning tool for communities to implement new comprehensive wastewater management strategies in order to improve estuarine water quality, according to the DEP.

The Herring River Estuary Restoration Project also recently received a $1 million state grant to help restore the estuarine habitat in the area.

The public comment period for this draft document ends Sept. 30 at 5 p.m. Written comments can be submitted to: Barbara Kickham, Department of Environmental Protection, Division of Watershed Management, 8 New Bond St., Worcester, MA 01606. Electronic format comments should be sent to