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PHOSPHORUS IN THE CHARLES RIVER: What you should know
Charles River, July 2008 - Photo by Maury Eldridge
1. What is phosphorus?
2. Where does phosphorus come from and how does phosphorus get into the Charles River?
3. What are the ecological effects of too much phosphorus entering the Charles River?
4. What are the human health effects of too much phosphorus entering the Charles River?
5. What can I do to prevent excess phosphorus from entering the Charles River?
6. What can my town or city do to prevent excess phosphorus from entering the Charles River?
7. What can my business or employer do to prevent excess phosphorus from entering the Charles River?
8. For more information
What is Phosphorus?
All terms in bold are explained here!
Combined sewer overflows: Overflows of raw, or partially treated, sewage combined with rainwater runoff into a water body. Combined sewer overflows, known as CSOs, occur in combined sewer systems (where rainwater runoff and household wastewater are carried by the same pipe) during heavy rain events
Cyanobacteria (blue-green algae): Photosynthetic bacteria that live and grow in aquatic environments. These organisms can produce toxins which are harmful to humans and other mammals in high doses. These organisms can give the water a green paint-like appearance (as pictured on the front cover) when present in large numbers.
Fish kills: sudden, massive die-off fish in a particular location in one water body
Low impact development (LID): design and development techniques used to construct a human environment that mimics the natural environment.
Nutrient: a substance an organism needs to live, which must be obtained from its external environment. Phosphorus and nitrogen are important nutrients for all plant life.
Stormwater bylaw: regulatory mechanisms adopted by municipal governments which define the administration and enforcement of the stormwater control measures that the US EPA requires of municipalities.
Stormwater (or rainwater) runoff: rainwater that runs along impervious surfaces such as roads and buildings, collecting pollutants and then flowing into local water ways.
Phosphorus is naturally present in rock, sediment, soil, and organic matter; in fact, it is the 11th most abundant element in the Earth’s crust. It is a non-metallic element represented by the chemical symbol P.
Phosphorus is a component of DNA and RNA and is, therefore, an essential element for all known living organisms. For humans, phosphorus is also an important component of our bones and teeth. Phosphorus is an essential factor in photosynthesis.
Plants must extract this nutrient from their environment during photosynthesis to make their food. In fresh water environments, like rivers and lakes phosphorus is the least naturally abundant nutrient required by aquatic plants and its absence usually limits the growth of aquatic plants.
Where does phosphorus come from and how does phosphorus get into the Charles River?
Phosphorus is naturally occurring but it is also found in a variety of man-made products such as lawn fertilizers, pesticides, “power” spray cleaners, deck and siding cleaners, shampoos, sunless tanning products, hair dyes, make up, skin care products, toothpaste, matches, soaps, detergents, oils, lubricants and auto exhaust.
From Environment, 3rd edition. by Raven & Berg
Phosphorus naturally enters rivers and other water bodies through erosion of rocks and soils, and the decomposition of dead plants and animals. (See image at right.) Today, however, human activities add a great deal more phosphorus to the Charles River than would occur naturally. The primary human sources of inputs of phosphorus to the Charles River come from: stormwater runoff, wastewater treatment facilities, illegal connections of sanitary sewer lines (which carry household wastewater) to stormwater drainage systems (which carry stormwater runoff to the Charles and its tributaries) and combined sewer overflows (CSOs).
Stormwater runoff includes nutrients from:
- lawn fertilizers;
- car wash runoff;
- auto exhaust, fuel and lubricants;
- septic leachate and failed septic systems;
- excessive amounts of sediment from construction sites and exposed earth;
- vegetative debris;
- waterfowl waste; and
- pet waste.
Stormwater runoff is a significant problem in the Charles River watershed, an area which has been extensively altered from its natural state, with a large amount of the land area built upon or paved over. When rainwater hits a rooftop or paved surface it cannot seep into the ground where it would naturally be filtered by soil and vegetation. Instead it flows over the impervious surface, collecting pollutants, and is funneled into storm drains where it is piped to the Charles River or a tributary.
Ultimately, due to common human activities and natural abundance, phosphorus is widespread in the environment. The larger the volume of stormwater runoff that enters the river, the larger the load of phosphorus it will carry with it.
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What are the ecological effects of too much phosphorus entering the Charles River?
A volunteer helping to remove invasive water chestnuts from the Charles River in Newton. These and other plants are able to grow prolifically because they are 'fertilized' by excess phosphorus in the river.
Adding phosphorus to a lake or river essentially fertilizes the aquatic system. As phosphorus is typically the nutrient limiting plant growth in fresh water systems, the addition of phosphorus allows more plants to grow. Algae, photosynthetic cyanobacteria and aquatic weeds can now grow in abundance, altering the natural balance of the aquatic ecosystem.
Excessive vegetation can block sunlight from penetrating the water, often choking out the submerged aquatic vegetation. Additionally, a bloom of aquatic plants may include a toxic blue-green algae or cyanobacteria. Certain algae produce toxins which are harmful to fish while toxic cyanobacteria can harm mammals. Additionally, when this large plant mass dies, the decomposition of the organic matter depletes the dissolved oxygen levels of the water, thus suffocating fish, mollusks and other aquatic animals. Decreased oxygen levels in the water column or blooms of toxic algae can cause mass die-offs of fish in aquatic systems, known as fish kills.
What are the human health effects of too much phosphorus entering the Charles River?
Phosphorus is not known to be toxic to humans or animals at any level. Nevertheless, fertilizing the Charles River with phosphorus can have adverse health effects for you, your children and your pets.
During the summers of 2006 and 2007, the Lower Basin of the Charles River experienced a bloom of toxin-producing photosynthetic cyanobacteria, also known as blue-green algae. These bacteria produce toxins which can be harmful to both humans and wild and domesticated animals. Exposure to toxins can occur through skin contact or ingestion. Unfortunately, toxins persist in the water and may pose the greatest threat after the bacteria has died off when there may no longer be visual evidence of the bloom. Symptoms associated with cyanobacteria contact are: diarrhea, upset stomach, vomiting, cramps, skin rashes, flu-like symptoms, allergy symptoms such as hay fever and asthma, and eye and ear irritation. Ingestion of water containing high concentrations of cyanotoxins or continued ingestion over time is suspected to cause severe liver disease, liver cancer, neurological impairment and in some cases death. When cyanobacteria are present in potentially dangerous levels in the Charles, CRWA works with state and local agencies to post signs advising the public of the potential threatFor more information on cyanobacteria, visit CRWA's blue-green algae web page.
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What can I do to prevent excess phosphorus from entering the Charles River?
There are many things you can do to reduce the amount of phosphorus that enters our local environment and reduce overall stormwater runoff volume to the Charles:
In everyday life:
- Do not feed wild animals, especially geese and ducks because their waste is a source of phosphorus. Feeding waterfowl allows the population to grow to unnatural levels which often cannot be sustained by the natural ecosystem. Sadly, this can ultimately lead to the death of some birds during the winter months when food is scarce.
- Walk, bike or take the T to nearby destinations; not only will this reduce your carbon footprint, it will also reduce the amount of nutrients being released into the environment.
- Pick up after your dog and then properly dispose of your dog’s waste in a garbage can or pet waste composter.
- Use only bio-based cleaners and solvents, which contain less phosphorus, for washing outdoor structures and equipment.
- Purchase phosphorus-free automatic dishwasher soap. Most other household cleaning products are required by law to limit their phosphorus content, and Massachusetts recently passed a law requiring manufacturers of automatic dishwasher soaps to reduce phosphates to trace levels by July, 2010. For more information on the impact of detergents on rivers, go to the Organization for the Assabet River website. Learn more about how household products contribute to phosphorus and other pollution problems in the Charles and criteria for household chemicals from Buta Full Life International.
In your yard:
- Don’t use fertilizer!
- Complete a soil test to determine if your lawn requires additional fertilizers. Many local soils don’t need any additional fertilizer. (Send your soil to be tested at UMass' Soil and Plant Tissue Testing Laboratory)
- Use mulch; it is good for plants and reduces the need to apply fertilizer.
- If your soil requires additional nutrients, use compost instead of store-bought inorganic fertilizers, or make your own compost at home, using leaves, grass clippings and other organic debris.
- If you must use fertilizer, use “slow-release” organic fertilizers which are broken down gradually by microbes in the soil so plants are able to use the nutrients over a longer period of time; less fertilizer is wasted by seeping into ground water or washing off into streams.
- Don’t use herbicides or pesticides as they also contain phosphorus. Consider pulling weeds manually or leaving some weeds in the ground for a more natural looking garden. Although phosphorus free pesticides exist, they cause other problems in water bodies in addition to excess phosphorus.
- Reduce areas of exposed soil on your property as soil runoff carries phosphorus to local waterways. This is especially important during renovations - make sure to speak to your contractor about sediment control measures.
- Collect stormwater runoff from your roof and store it in rain barrels or an underground rainwater recovery system. With additional plumbing, this stored water can be tapped into garden hoses, toilets or other household uses. Go to the Rainstay web page to learn about Smart Storm, a rainwater collection system developed by CRWA (photo at left).
- Visit a car wash, where water is treated and recycled, instead of washing your car in your driveway.
- Conduct regular maintenance on your septic system to prevent backups and a potential release of phosphorus.
- When constructing driveways, patios or sidewalks, use permeable pavers to infiltrate stormwater into the ground.
- Plant a rain garden to collect and filter stormwater runoff from rooftops and driveways.
- Build a green roof to absorb rain water, reduce runoff from your roof and lower energy costs. Green roofs are not just for flat roofs!
- Do not deposit grass clippings in the river or on the river bank, as they contain phosphorus. Keep them in a compost bin and use them later as a mulch.
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What can my town or city do to prevent excess phosphorus from entering the Charles River?
- Prohibit the use of fertilizers, pesticides or herbicides on town parks and athletic fields. (Although phosphorus free pesticides exist, pesticides cause other problems in water bodies beyond phosphorus addition.)
- Preserve natural vegetation buffers along river and stream banks to help filter stormwater runoff.
- Capture and treat stormwater runoff using biofiltration mechanisms which filter runoff through engineered soils and vegetation to remove phosphorus.
- Infiltrate stormwater runoff into the ground as groundwater wherever possible and appropriate, since phosphorus is highly absorbable by soils.
- Adopt a stormwater or low impact development (LID) bylaw that promotes the use of LID stormwater best management practices.
- Consider traditional stormwater piping systems, which funnel untreated runoff to local waterways as quickly as possible, to be a last resort.
What can my business or employer do to prevent excess phosphorus from entering the Charles River?
Large commercial and industrial developments are a significant source of phosphorus to the Charles River because of their large impervious areas. Encourage your employer to:
- Prohibit the use of fertilizers, pesticides or herbicides on landscaped areas.
- Capture and treat stormwater runoff from parking lots and rooftops using biofiltration mechanisms which filter runoff through engineered soils and vegetation to remove phosphorus.
- Infiltrate stormwater runoff from parking lots and rooftops into the ground as groundwater wherever possible.
- Build a green roof to absorb water and prevent rainwater runoff from your building. These also reduce energy costs!
- Promote the use of public transportation or ride sharing.
- Be aware of sediment control measures during construction/renovation of buildings.
- Use low-phosphorus or phosphorus-free cleaning products. Many commercial grade cleaning products have higher phosphorus contents than household cleaning products.
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For more information
Download a printable brochure (PDF) about phosphorus and the Charles River
CRWA Best Management Practices fact sheets page - download PDFs of our information sheets on green roofs, rain gardens, permeable pavement, permeable pavers, vegetated swales, and other techniques
Learn more about how household products contribute to phosphorus and other pollution problems in the Charles, and criteria for household chemicals, from Buta Full Life International
Learn about CRWA’s Total Maximum Daily Load (TMDL) study to determine the amount of phosphorus and other nutrients that are safe for the Charles
Get information detergents in rivers from the Organization for the Assabet River
Final Total Maximum Daily Load for Nutrients in the Lower Charles River Basin, Massachusetts. Massachusetts Department of Environmental Protection and US Environmental Protection Agency, June 2007.
Massachusetts Department of Public Health guidelines for cyanobacteria in freshwater recreational water bodies in Massachusetts.
Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen. In Issues in Ecology, Summer 1998.
Occurrence of Cyanobacterial Toxins (Microcystins) in Surface Waters of Rural Bangladesh: Pilot Study Report, May 2004. World Health Organization.
Phosphorus Chemistry: Uses. Department of Chemistry, University of Massachusetts.
Phosphorus in Soil and Water. Manitoba Agriculture, Food and Rural Initiative.
Streamflow, Water Quality, and Contaminant Loads in the Lower Charles River Watershed, Massachusetts, 1999-2000. USGS Water-Resources Investigations Report 02-4137.
Water Quality Assessments: A Guide to Use of Biota, Sediments and Water in Environmental Monitoring, Second Edition.
Water Quality Monitoring Manual, 12th Edition. CRWA, 2006.
This web page sponsored by the Non-Point Source "Find It and Fix It" Program in the Charles River and Mystic River Watersheds. This project was funded by the Massachusetts Environmental Trust.
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