Pollution on Cape Cod

Cape Cod, Massachusetts, is a hook-shaped peninsula extending into the Atlantic Ocean from the southeastern corner of Massachusetts in the northeastern United States. It encompasses a variety of ecosystems, including marine, estuary, freshwater, and terrestrial environments, which provide vital habitats and breeding grounds for a diverse range of animals, including endangered North Atlantic right whales and humpback whales. Additionally, the region supports commercial fisheries and shellfish farming operations with substantial economic value.

The presence of excessive nitrogen-based chemicals in the waters of Cape Cod Bay enters the water faster than it can exit, taking approximately one month for the waters to be entirely drained and refilled. This leads to the accumulation of toxic levels of nitrogen compounds. The primary sources of this nitrogen (around 80%) are septic systems, fertilizer runoff and pollutants from nearby parking lots. The excess nitrogen caused eutrophication, leading to toxic algal blooms and depleted oxygen levels (hypoxia) in the bay.

Efforts to address this issue are ongoing, and one proposed strategy involves the expansion and creation of sewer systems throughout the area to reduce the input of nitrogen compounds. Researchers continue to study and monitor the situation to find effective solutions to mitigate the environmental impacts and preserve the delicate balance of the Cape Cod ecosystems.

Background

On Cape Cod, small inland ponds known as Kettle ponds and the surrounding waters of the Atlantic Ocean have become increasingly polluted over the years. The main pollutant considered to be problematic in these waters is nitrogen. The high amount of nitrogen in the water stems from the widespread use of private septic tanks in homes instead of the use of a town-owned sewer. Many towns around Cape Cod opted out of purchasing sewer systems when the federal government subsidized them in the 1960's and 1970's to avoid the influx of new homeowners to the communities. However, Cape Cod's communities grew despite the lack of public sewage systems, resulting in the installation of many septic tanks in new homes.

The increased nitrogen levels in the waters of Cape Cod increased algae blooming in the spring and summer months as it is a key nutrient. Death of the algae creates a thick buildup of slime on the bottom of the bays and ponds, which severely reduces the amount of shellfish and crabs able to survive on the seafloor. The algae also limits the amount of available oxygen in the water, which asphyxiates the fish living there. Algae is also a source of red tides, which have been occurring more frequently with the heightened nitrogen levels.

Attempts to counter the problem by affected towns include new programs and procedures to reduce the levels of nitrogen present in the waters of Cape Cod. The most commonly proposed solution is to install new town-wide sewer systems to prevent runoff from septic tanks reaching the water, since sewer systems release less nitrogen into the environment than private septic tanks.