The Impact of Phosphorous Pollution on Water Bodies

     As Americans, we often take clean drinking water for granted. However, we have seen several examples lately of municipal water supplies being choked off by the results of phosphorus pollution and excessive algae blooms. Take, for example, what occurred in Toledo in August 2014. Residents were warned not to drink the water coming from their taps. Lake Erie, a major source of the city’s drinking water, was polluted by toxic algal blooms, which were fed by excess nutrients.

What is Phosphorous Pollution?

     In certain amounts, phosphorous is a critical nutrient for supporting life in freshwater systems. But as with anything, when things get out of balance, water with too much phosphorus can cause toxic cyanobacteria blooms. This process of nutrient accumulation and aging water bodies is called eutrophication.

     Excess phosphorus enters lakes and ponds from runoff, sewage, and other decomposing matter. Eutrophication in freshwaters has been accelerated by human activities – mainly runoff from fertilized farmland or golf courses and human discharge from wastewater plants. All of this additional phosphorous feeds and promotes toxic cyanobacteria. The cyanobacteria, in turn, can deplete oxygen from the freshwater and block sunlight from reaching past the surface, which means plant and aquatic life are threatened. The toxins can also directly threaten all organisms that use the water.

Attempts to Manage Phosphorus Pollution

     Across the country, regulations have been passed in an attempt to reverse (or at least) slow the influx of phosphorous into water bodies. In particular, farmers and fertilizers used in farming have been targeted. The EPA regulates certain types of phosphorus used in farming to determine which are least detrimental to the health of the soil and nearby water bodies. Farmers are also required to create buffer zones and practice different tilling techniques to minimize runoff.

     Other programs have aimed to change farming practices without regulation. For example, some use cost-sharing. This way, each individual farmer doesn't take a big financial hit when transitioning to new methods.

     However, pointing fingers at farmers won’t solve the phosphorus pollution problem. Everyone needs to work together to solve this problem, and we need to investigate other sources of phosphorus. Think about this: a flock of geese can fly over a lake and drop a lot of phosphorus, too – but it’s a harder to regulate geese than to regulate farming practices! We have to look broadly to truly make a difference. Also, since phosphorus has continually built up over many years/decades in these water bodies, the internal recycling can be a significant contributing factor to lake health.

Impacts Go Beyond Drinking Water

     Beyond concerns about drinking water, reducing phosphorus pollution is important for other reasons. It can protect water used for irrigation and livestock, and it can benefit the environment as a whole – including species that live in and around water bodies. Cleaning up our water won’t be done overnight, but it’s a long-term investment in our health and environmental stewardship.


West Bishop is the Algae Scientist and Water Quality Research Manager at SePRO Corporation. He has an M.S. in Aquatic Toxicology from Clemson University and is a Certified Lake Professional through NALMS. He blogs about algae management and other algae-related topics for StewardsOfWater.com.