Phosphorus

What are Phosphates?

Phosphates are the most common form of phosphorus. Phosphorus is an element and critical nutrient required by all life. While phosphate plays a very important role as a nutrient in aquatic ecosystems, it is difficult to monitor due to its low concentration and the fact that it can appear in both organic and inorganic forms.

Why is phosphate important?

Phosphate plays a very important role as a nutrient in aquatic ecosystems. However, it is difficult to monitor due to its low concentration and the fact that it can appear in both organic and inorganic forms. Often, water quality monitoring focuses on measuring total phosphorus rather than phosphate concentrations.

While phosphorus is critical to all life, too much nutrients in the water can lead to water quality issues. High levels of phosphates can contribute to the formation of harmful algal blooms (HABS) and nuisance algae, like cladophora. Phosphorus makes its way into our waterways from sources such as stormwater, urban and agricultural runoff, sewage and wastewater discharges, and erosion. Many fresh and marine waterbodies are monitored for phosphorus.

What does the level of phosphorus mean for freshwater health?

• 1 – 3 ug/L – the level in uncontaminated lakes
• 2.5 – 10 ug/L – level at which plant growth is stimulated
• 10 ug/L – maximum acceptable to avoid accelerated eutrophication
• > 10 ug/L – accelerated growth and consequent problems

Converting phosphates to phosphorus – multiply phosphorous value by 3.066.