Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The endpoints "Phototransformation of an element in water, soil or air" are not relevant for substances that are assessed using a read-across aproach on an elemental basis, i.e., based on the exposure and effects of molybdenum, expressed as elemental Mo.

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.

As mentioned previously, in the case of the current substance the chemical safety assessment is based on elemental metal concentration, i.e., the assessment of molybdenum is conducted regardless of the (pH-dependent) speciation in the environment. Hence, as the assessment is based on the element concentration (i.e., Mo as molybdate), physicochemical processes like decomposition and degradation by reaction with water are not relevant. This elemental-based assessment (pooling together of all speciation forms) 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.