Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Diphosphorus pentaoxide is hygroscopic forming with water an aqueous solution of phosphorus oxyacids (primary hydrolysis) which are subject to further (secondary) hydrolysis to the end product phosphoric acid, H3PO4.

 

Hydrolysis of P2O5in water under conditions relevant for ecotoxicological studies (100mg/L, 25°C) leads to slightly acidic solutions(pH 3.6) with the main product of tetraphosphoric acid. Further hydrolysis within the time frame of ecotoxicologicalstudies is insignificant.

 

Under environmental conditions the hydrolysis products are available as different phosphate (Na, K, Ca). Phosphate and phosphorus are an essential nutrient of microorganisms, plants and animals. Phosphoric acid is readily utilizable by aquatic plants and microorganisms. Phosphorus compounds are an important component of living matter and all organisms contain a certain quantity; however, a bioaccumulation is very unlikely due to natural metabolic processes for essential nutrients. It can be stated that a bioaccumulation test is not warranted. This statement given above is in line with the specific rule in 1907/2006/EC Annex IX, section 9.3.2, column 2: “The study need not to be conducted if the substance has a low potential for bioaccumulation and a low potential to cross biological membranes.”