Registration Dossier

Diss Factsheets

Environmental fate & pathways

Hydrolysis

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

According to Annex XI of regulation (EC) 1907/2006, testing for a specific endpoint may be omitted if testing does not appear to be scientifically necessary or if it is technically not possible to conduct the study as a consequence of the properties of the substance. Under REACH (ECHA 2008, Chapter R.7B – Endpoint Specific Guidance), the term ‘Hydrolysis’ refers to the “Decomposition or degradation of a chemical by reaction with water”, and this as a function of pH (i.e., abiotic degradation). According to Guidance on information requirements and chemical safety assessment; Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds, “Biotic and abiotic degradation rates should be set to zero for metals”. In the case of inorganic substances, like Struvite, the chemical safety assessment is generally based on total (dissolved) ion concentrations for Mg2+, PO43- and NH4+, regardless of their (pH-dependent) speciation in the environment. Therefore, physicochemical processes like degradation or transformation by reaction with water are judged not relevant. Depending on the prevailing environmental conditions, formation of different species may occur, but the chemical assessment will not make any differentiation among the different species. In conclusion, (abiotic) degradation is an irrelevant process for inorganic substances, thus testing for hydrolysis is not required.