Eutrophication Potential

Eutrophication Potential (EP) covers the impacts on terrestrial and aquatic environments due to over-fertilisation or excess supply of nutrients, particularly focusing on the most important substances nitrogen (N) and phosphorus (P) (Guinée, 2004, p. 82). The enrichment of nutrients leads to increased growth of plants, especially plankton algae, consumption of oxygen by bacteriological degradation of dead biomass, which can change the composition of species. Another impact can be the change of character of a lake, for example: a formerly clean lake with drinking water quality can evolve into water with an anoxic (free of oxygen) depth layer (Kloepffer and Grahl, 2014, p.261). The impacts of eutrophication on terrestrial ecosystem are changes in function and diversity of species.

The Eutrophication Potential is expressed as Phosphate (PO4)-equivalents.

The European Space Agency is differentiating within the impact category Eutrophication Potential between “Freshwater Eutrophication Potential” and “Marine Eutrophication Potential”.

Phosphorus (P)/ Phosphate (PO4):

Pure “elemental” phosphorus (P) is rare, as it usually exists as part of a phosphate molecule (PO4) (United States Environmental Protection Agency, 2012).

Phosphorus is a vital element necessary for the growth of plants and animals and in lake ecosystems (Water Research Center, 2014).

Phosphate-equivalent (PO4-eq.):

Phosphate-equivalent is a measure to estimate the Eutrophication potential of substances. The substances are being converted to the same amount of Phosphate with the same Eutrophication impact.

Example:

1 kg Ammonia has a Eutrophication potential of 0.35 kg PO4-equivalents, meaning the Eutrophication Potential of 1 kg Ammonia and 0.35 kg Phosphate are equal.