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Sources of Phosphorus


Phosphorus is naturally present in the earth and it is also added to the environment through other sources including fertilizers, detergents, and human and animal feces. 

The following list provides a description of the different sources for phosphorus along with a brief description of how each source is managed and what can be done to minimize over use.

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  • Food and Drug Industry

    Phosphates are added to lunch meats, cheese, canned tuna, non-dairy coffee whiteners and multi-vitamins. Calcium and sodium phosphates are added to toothpaste for their mild abrasiveness and effective whitening properties. Phosphates are also used as fluoride carriers to minimize tooth decay. Phosphate salts in baking products act as leavening agents that "fluff up" foods, such as cakes, biscuits, breads and pancakes.

  • Detergents

    Phosphates were once commonly used in laundry detergent in the form trisodium phosphate (TSP).   Under the Concentration of Phosphorus in Certain Cleaning Products Regulations, all commercial and industrial laundry detergents must contain less than 2.2 per cent elemental phosphorus. Household detergent limits were reduced from 2.2% to 0.5% % on July 1, 2010.  Phosphates soften water, help suspend dirt, emulsify oil and grease and contribute to the reduction of germs. Phosphates tie up water hardness minerals (primarily calcium and magnesium) so that the minerals won't interfere with cleaning or be deposited on surfaces. Phosphates also help keep food soil particles in suspension after removal from the soiled surfaces.

  • Dishwasher Detergents and Household Cleaners

    The elemental phosphorus content of household automatic dishwasher detergent and household cleaners manufactured for sale in Canada was regulated to a maximum of 0.5 per cent by weight, effective July 2010.

    Some suggest that environmentally friendly detergents with enzymes are  effective for cleaning dishes. Wiping dishes and pots and pans before loading them into the dishwasher helps.

  • Agriculture

    In agriculture, phosphate is one of the three primary plant nutrients that is a component of fertilizers. Normally phosphorus is chemically treated to make superphosphate, triple superphosphate, or ammonium phosphates, which have a higher concentration of phosphate and are also more soluble, therefore more quickly usable by plants. 

    Phosphates are also found in manure.   A mature dairy cow produces about 30 times more phosphorus waste than a human. The Nutrient Management Act, 2002 was established to help control manure spreading to minimize conveyance of nutrients into water bodies.  The Ontario Minister of Agriculture, Food and Rural Affairs promotes the use of best management practices for protecting surface and ground water.  The Ontario Drinking Water Stewardship Program  provides some information for protecting surface water that is close to drinking water sources.  Funding is available to farmers through an number of programs offered under  the Clean Water Program, which is administered  by Conservation Areas. The City of London's contribution to the Upper Thames River and Kettle Creek Conservation Authorities help to fund the programs.

  • Car Washing

    Washing cars at home in your driveway can be bad for the environment because the wash water can enter the storm sewer system and pollute waterways. It is much better to use commercial car washes because the wash water is recycled and sent to a sanitary sewer for proper treatment. Oil and grit from the wash is also properly disposed in a landfill. Commercial car washes use at least half the amount of water than a typical driveway car wash. There are also eco-friendly phosphate-free commercial car wash products available. The City of London has a Washing Your Car brochure to help provide more information.

    Community car washes (for fund-raising) are discouraged if the location permits the wash water drains to the storm sewers and local rivers.  On June 15, 2013 a Charity Car Wash was held in conjunction with the Canadian Car Wash Association in London to raise money for the City of London Food bank.

    If commercial car washes are not available:

    1. Park over grass or other porous surfaces to allow infiltration
    2. Use eco friendly soaps
    3. Plan community car washes on grassed areas.
    4. Dispose of soapy water down the sanitary drain.
    5. Minimize water use by washing the vehicle in sections.
  • Wastewater

    London's sewage is treated at six pollution control plants.  Phosphorus concentrations are reduced to levels well below the approved limits allowed by the Ontario Ministry of the Environment.  Phosphorus enters our treatment plants in concentrations of about 5.8 mg/L and about 90% is removed before discharge at about 0.5 mg/L. On average about 17% of the phosphorus loading to the river is from wastewater treatment plants. 

    A Pollution Control Plant Discharge Strategy (March 2008) Master Plan was completed with the recommendation to minimize phosphorus loading to the Thames River by reducing concentration limits with future plant expansions.

    Phosphorus can also enter waterways from septic systems. Owners of septic systems are encouraged to ensure the systems are functioning properly and that septic tanks are regularly cleaned out. 

    The Ontario Minister of Agriculture, Food and Rural Affairs website provides some tips for the care and maintenance of septic systems.

  • Storm Water

    London has a variety of Stormwater Management Facilities that are used to trap sediment and pollutants from urban runoff.   Facilities include oil/water separators, in-ground pipe storage and dry and wet ponds.

    Londoners should always keep in mind that our storm water system collects runoff from each of our properties and accordingly we should be careful keep our cars and motor cycles leak free and limit the use of fertilizers or chemicals on our lawns.

    Surface runoff eventually outlets to the Thames River

  • Lawn and Garden Fertilizers

    Lawn fertilizers can contain a significant quantity of phosphorus. Home owners are encouraged to select a phosphorus free fertilizer as an alternative.  Check the N-P-K (Nitrogen-Phosphorus-Potassium) formula and look for a 0 in the middle digit for a phosphorus free formula.

    Some experts suggest that additional phosphorus is only needed for a new lawns and that existing lawns would have sufficient phosphorus in the established soil. 

    For a healthy lawn, keep the grass blades longer and keep the grass clippings on the lawn to provide nitrogen.

  • Animal Waste

    Wildlife,bird and pet droppings are also a significant source of phosphorus and other contaminants.

    Owners should always pick up after their pet and ensure that the waste is properly disposed of in a garbage receptacle for landfill disposal.  Don't leave bags of pet waste in parks, forests or wooded areas.  Take the waste home and dispose of feces in the garbage.

    Don't feed wildlife including ducks and geese.  Feeding wildlife changes their habits and leads to expanding populations and increased phosphorus and bacterial loading into our streams and rivers.