Water quality tests in the lab
Monitoring nutrients and harmful algal blooms (HABS) in water

Total phosphorous

What is total phosphorus?

Total phosphorus measures the concentration of inorganic phosphate ions dissolved in a sample of water as well as the quantity of phosphorus contained in the suspended organic matter. Aquatic organisms are able to take it up quite efficiently and as a result concentrations in pristine water are generally quite low.

Total phosphorus levels can be high in areas of agricultural runoff, leading to increased growth of algae and other aquatic vegetation.
Total phosphorus levels can be high in areas of agricultural runoff, leading to increased growth of algae and other aquatic vegetation.

Why is total phosphorus important?

Phosphorus is the key nutrient for photosynthesis. Phosphorus concentrations determine the quantity of plankton and algae a body of water can support. Soil erosion is a main contributor of phosphorus to a body of water. However, if there is too much in the water it can speed up eutrophication (excessive amounts of nutrients cause low levels of dissolved oxygen in the water).

What does a measurement mean?

Different areas will have different baseline readings. These are the ranges we typically look at:

  • 1 – 3 ug/L – the level in uncontaminated lakes. Very little aquatic vegetation.
  • 5 – 10 ug/L – level at which plant growth is stimulated. A nutrient-poor lake with clear water which supports some algae and phytoplankton.
  • 10 – 20 ug/L – A lake which supports a moderate degree of vegetation.
  • > 20 ug/L – accelerated growth and consequent problems: Likely a body of water with phosphorus input from outside sources.

Water Rangers Protocol

We do not currently include a test for this in our kit. However, we are conducting research on ultra-high level phosphate detection (such as during a pollution event).