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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Ecotoxicological Summary

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Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Phosphorus is an essential nutrient of microorganisms, plants and animals. is usually the limiting nutrient in ecosystems: it Phosphoric acid can be readily utilisable by aquatic/terrestrial plants and microorganisms. Phosphorus compounds are an important component of living matter and all organisms contain a certain quantity; however, excessive bioaccumulation is unlikely due to natural metabolic processes for essential nutrients (Frausto da Silva & Williams, 1991). Thanks to its high water solubility and low vapour pressure, phosphoric acid is mainly found in soil (migrating towards the groundwater table) and water compartments: there, phosphoric acid progressively dissociates affecting the pH of the receiving compartment.

Phosphoric acid progressively dissociates as pH is raised from about 3.0 to above 7.0.

H3PO4<=> H++ H2PO4-<=> 2H++ HPO42 -<=> 3H++ PO43 -; respectively pKa 2.2; pKa 7.2; pKa 12.3.

The third H+ is generally only lost in alkaline conditions. Under relevant environmental pH range (pH5 to pH8), the monovalent and divalent phosphates are dominant (H2PO4-and HPO42 -). As reported in "Acid soils of the tropics" (Harder RD) because of this dissolution, when phosphorus fertilizer is placed in a band, very low pH values can be attained. The acidity will then gradually diffuse into the soil surrounding the band. According to Lindsay and Stephenson (1959), pH values as low as 1.5 can be found in a zone immediately around a fertilizer band. Natural pH can vary significantly as well as organisms sensitivity in adapting to such change. A pH range of 6 -9 is generally considered safe for aquatic organisms. Moreover, pH change due to anthropogenic release of phosphoric acid is influenced by the buffer capacity of the receiving water.

References:

Frausto da Silva JJR and Williams RJP, The Biological Chemistry of the Elements: The Inorganic Chemistry of Life; Oxford University Press: Oxford, 1991.

Harder RD (2002) Acid soils of the tropics, An Echo Technical Note

Lindsay WL and Stephenson HF (1959) Nature of the reactions of monocalcium phosphate monohydrate in soils, Soil Sci. Soc. Am. J. 23(1): 12-

Conclusion on classification

Phosphoric acid is not considered to be classified as toxic to the aquatic environment.