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What is Phosphorus?

Phosphorus is a nutrient vital to human, animal, and plant life that occurs naturally in our food, water, and bodies, as well as, in human and animal waste.   In nature, phosphorus usually exists in the form of  phosphate molecules that are formed from plant or animal tissue.  Both organic and inorganic phosphate can be dissolved in water or become attached to other particles in water.

Why is too much phosphorus bad?

Too much phosphorus in  freshwater systems can set off a whole chain of undesirable events including  accelerated plant growth, algae blooms, low dissolved oxygen, and the death of  fish, invertebrates and other aquatic animals.  

Phosphorus and Algae

High phosphrous levels could make algae spread across the water surface in floating blooms that prevent sunlight from reaching the underlying plants.  As a consequence, plants die and decompose and micro-organisms that feed on dying plants could also consume too much of the oxygen in the water body, leaving fish and other aquatic life to die.

Phosphorus and the Thames River

Like most rivers in Southern Ontario, background levels of total phosphorus exceed the Provincial Water Quality Objectives (PWQO).  In London, total phosphorus levels are about 4 times higher than the PWQO concentration enterning the City and by about 5 times the concentration leaving the City.  Accordingly, the Thames River is designated as a " Policy 2"  river which means that waters should not be degraded further until all practical measures are taken to upgrade the water quality to the Objectives. In recognition, London's Pollution Control Plant Discharge Strategy lead to a decision to reduce the quantity of phosphorus discharges with future treatment plant expansions.