Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

refer to "Justification for classification"


Short description of key information:
Diphosphorus pentaoxide is a hygroscopic solid which forms with moisture/water an aqueous solution of phosphorus oxyacids (primary hydrolysis) that are subject to further (secondary) hydrolysis to the end product phosphoric acid, H3PO4. The exposure to Diphosphorus pentaoxide under physiological conditions (aqueous system) will principally lead to local (genotoxic) effects due to the strong corrosivity of the generated phosphoric acid. Therefore, a read across to the data generated with Phosphoric acid is justified.
Mutagenic activity of Phosphoric acid was investigated in two bacterial reverse mutation assays (Ames test; test strains used: S. typhimurium TA97, TA 98, TA 100, TA 104, TA 1535, TA 1537 and E. coli WP2 uvr A), and in an in vitro chromosome aberration study in mammalian cells (Chinese Hamster Lung). Negative results were obtained in all tests with and without metabolic activation.

Furthermore, no genotoxcity was observed in a gene mutation study (HPRT test) with Diphosphorus pentaoxide performed in V79 Chinese hamster lung fibroblasts.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Diphosphorus pentaoxide is a hygroscopic solid which forms with moisture/water an aqueous solution of phosphorus oxyacids (primary hydrolysis) that are subject to further (secondary) hydrolysis to the end product phosphoric acid, H3PO4. The exposure to Diphosphorus pentaoxide under physiological conditions (aqueous system) will principally lead to local (genotoxic) effects due to the strong corrosivity of the generated phosphoric acid. Therefore, a read across to the data generated with Phosphoric acid is justified.

Phosphoric acid did not show chromosome aberrations regardless of application of metabolic activiation in a chromosome aberration study using Chinese hamster lung cells (CHL/IU). Phosphoric acid was also considered to be non-genotoxic in the bacterial reverse mutation test.

Furthermore, no genotoxcity was observed in a gene mutation study (HPRT test) with Diphosphorus pentaoxide performed in V79 Chinese hamster lung fibroblasts.

 

It can be concluded from the data available that mutagenicity and genotoxicity are not caused by Phosphoric acid and also by Diphosphorus pentaoxide (which hydrolyses in aqueous solutions completely to Phosphoric acid). Therefore, a classification for this endpoint is not warranted.