Nutrients

Nutrients, such as phosphorus and nitrogen, are carried by stormwater into receiving waterbodies, causing algal blooms and excessive plant growth. This process, called eutrophication, makes recreation in lakes difficult, kills fish, turns the lake green, causes foul smells, and decreases oxygen levels. Many lakes and ponds in the Mystic River Watershed suffer from eutrophication, including Spy Pond, Bellevue Pond, and Horn Pond.

How You Can Help

Three of the main sources of nutrient pollution are fertilized lawns, car washings, and automatic dishwasher detergents. By changing your actions, you can help clean our waterways.


Source: MyRWA, Roger Frymire

Lawn Fertilizers

Lawn and plant fertilizers are primarily composed of phosphorus and nitrogen, two of the building blocks of life. In addition to making your grass grow, they are the fuel needed for the growth of algae. After a storm, fertilizers are picked up in stormwater runoff and whisked into gutters that direct them to waterbodies or the stormwater takes them directly to the waterbodies. Lakes are usually the hardest hit by eutrophication.

What You Can Do

  • Test your lawn to make sure it actually needs fertilizer. Don't overfertilize!
  • Plant native plants instead of grass that don't need fertilizers.
  • Do not fertilize before a heavy rainstorm.
  • Mulch grass clippings into your lawn instead of fertilizing.
  • Use compost instead of fertilizers. Contact your town's Department of Public Works to see if you can get a compost bin at a reduced price.
  • Buy phosphorus free fertilizers.


    Source: Puget Sound Action Team

Washing Your Car

Every time you wash your car in your driveway or the street, nutrient rich detergent enters the storm drains. Water in the storm drains goes directly into nearby waterbodies, thereby causing pollution.

What You Can Do

  • Use a commercial car wash- they often recycle and clean their water.
  • Wash your car on a permeable surface, such as grass or gravel so water won't go into the storm drain.
  • Use biodegradable soaps.


Source: Puget Sound Action Team

Automatic Dishwashing Detergents

Automatic dishwashing detergents contain phosphorus that is a source of eutrophication and low dissolved oxygen levels in local rivers and lakes. Automatic dishwashing detergents can have up to 8.7% of phosphorus by weight. According to the Environmental League of Massachusetts, the MADEP believes that 8-17% of the phosphorus load in wastewater treatment plants from domestic sewage comes from these detergents. Alternatively, the Charles River Watershed's engineers believe the percentage may be as high as 34%. During large storm events, phosphorus laden water in combined sewer overflows is released directly into waterbodies, untreated.

What You Can Do

  • Buy automatic dishwashing detergents that do not contain phosphorus. Examples include: Ecover, Seventh Generation, Bi-O-Kleen, and Shaklee. Most can be found in local grocery stores such as Shaws/Star Market, Trader Joe's, and Whole Foods.
  • Support Senate bill 1252 that will limit the amount of phosphorus in automatic dishwashing detergents that is sold in Massachusetts.
  • If you must buy detergents that contain phosphorus, buy ones that have lower amounts of phosphorus, such as Palmolive Gel. Check out http://www.assabetriver.org/nutrient/detergents.html for a chart on phosphorus contents in detergents.
  • Another source of phosphorus from your kitchen is food put down the disposal. Instead of putting it in your disposal, compost it- this reduces the need for phosphorus laden fertilizers and keeps phosphorus out of the water! For more information on obtaining a compost bin at reduced costs, contact your town's Department of Public Works.