Registration Dossier

Environmental fate & pathways

Hydrolysis

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Description of key information

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). The need for testing may be waived if “The substance is highly insoluble in water”, or if “The substance is readily biodegradable”. The latter property of a substance assumes a rapid mineralization of the substance and therefore hydrolysis tests will provide little information.

Key value for chemical safety assessment

Additional information

In the case of the current substance - lead - the chemical safety assessment will be based on elemental metal concentrations, regardless of their (pH-dependent) speciation in the environment. Hence, as the assessment is based on the element concentration (i.e., Pb), physicochemical processes like decomposition and degradation by reaction with water are not relevant. Formation of different Pb-hydroxides may occur, but the chemical assessment will not make any differentiation among the different Pb-species (pooling of different speciation forms). This elemental-based assessment (pooling all speciation forms together) can be considered as a worst-case assumption for the chemical assessment. In general, (abiotic) degradation is an irrelevant process for inorganic substances that are assessed on an elemental basis.