Septic systems and fertilizers are biggest bay polluters

By Caitlin Flaherty


Nitrogen, itself, is not so bad. In fact, it’s necessary for life and found in all living things. However, too much nitrogen causes too much algae to grow. The algae block sunlight and cause the eelgrass on the bay floor to die. To make matters worse, when algae die and decay, it takes oxygen from the water, causing fish to suffocate and die as well.

Although nitrogen does come from some natural surfaces, here is a look at the most common causes of nitrogen pollution–all caused by people:

 nitrogen sources

In order to help reduce nitrogen to waterbodies in Massachusetts, scientists and environmentalists need to look at exactly where it is coming from.

The Massachusetts Estuary Project, a partnership between towns, the MassDEP and U-Mass Dartmouth School for Marine and Science Technology, recently released another draft of its report on the Wareham River Estuary.

According to the 160-page report, all of the water bodies in the Wareham River Estuary are moderately impaired, but the Lower Wareham River and Marks Cove are significantly impaired. Overall, the MEP states that nitrogen loading needs to be reduced by 40 percent.

From this data, they can determine just how much nitrogen each waterway can handle.  This is called a nitrogen threshold, which is then used to develop a Total Maximum Daily Load (TMDL).

Here’s what they found in the Wareham River Estuary:

nitrogen pie chart

About Caitlin Flaherty 2 Articles
Caitlin Flaherty is a journalist finishing up her graduate degree at Emerson College. She works as a staff reporter for the Wareham Courier, covering all local news.