What is Phosphorus?
There are many uses of phosphorus. However, its use as an ingredient in fertilizers has both benefits and problems. Phosphorus is known as a nutrient. Nutrients are essential to all plant life on land and in the water as a vital component in the process of converting sunlight into usable energy forms for the production of food and fibre. Although nutrients are essential to life, their presence at high concentrations can be harmful. This is especially true of phosphorus.

Nutrients occur naturally, but human activity has dramatically increased the amount of phosphorus released into the environment. When the rivers and lakes were surrounded mostly by forest and wetlands, much less nitrogen and phosphorus ran off the land or leached into the water. Most of it was bound or held in place by the natural vegetation. Today, with forests and wetlands replaced by farms, cities, and suburbs, nutrients are entering water supplies in much greater quantity.

How does Phosphorus enter our water?
Phosphorus occurs naturally in rocks, soil, animal waste, plant material, and even the atmosphere. In addition to these natural sources, phosphorus comes from human activities such as agriculture, discharge of industrial and municipal waste, and surface water runoff from residential and urban areas. Nutrients held in soil can be dissolved in water and carried off by leaching, tile drainage or surface runoff.

How does Phosphorus affect human health?
Phosphorus does not pose a direct threat to human health; it is an essential component of all cells and is present in bones and teeth. It does, however, pose an indirect threat to both aesthetics and to human health by affecting source waters used for drinking and recreation. For example, excessive nutrients can promote the growth of algal blooms, which can contribute to a wide range of water quality problems by affecting the potability, taste, odour, and colour of the water.

How does Phosphorus affect the aquatic environment?
In the aquatic environment excess amounts of phosphorus and nitrogen cause rapid growth of algae and phytoplankton, creating dense populations, or blooms. This process is called eutrophication. These blooms can become so dense that they reduce the amount of oxygen and sunlight available to aquatic organisms and vegetation . Without sufficient light, plants cannot photosynthesize and produce the food they need to survive. Algal blooms will ultimately sink and be decomposed by bacteria in a process that consumes oxygen in deeper waters, sometimes suffocating aquatic organisms.

What are the Phosphorus guidelines?
The Federal-Provincial-Territorial Committee on Drinking Water has not developed a guideline for phosphorus in drinking water, as it is not directly toxic to humans.

Currently, there are no national guidelines for phosphorus for the protection of aquatic life. The CCME Water Quality Task Group is developing a Framework for the Management of Phosphorus in Freshwater Systems to address this issue.

What can individuals do to help?
To limit phosphorus in water supplies:

• Limit fertilizer use and apply at appropriate times. Nutrients in chemical fertilizers can run off from yards into local waterways, If you must fertilize, always follow the application instructions. Never over-fertilize.
• Control runoff and soil erosion. Limiting erosion and preventing runoff will reduce the amount of sediments and nutrients entering the watershed.
• Start a compost pile and recycle yard waste. This will reduce waste and provide a natural fertilizer.
• Plant trees. Trees filter and control polluted runoff, take up nutrients, and reduce soil erosion.
• Maintain your septic system. Without regular pumping, septic tanks can fail, affecting the environment and contaminating drinking water wells.
• Be a responsible boater and pump out wastes at designated areas. Raw sewage causes pollution that harms human and aquatic health.