Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Abiotic degradation

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

 

The termHydrolysis” refers to theDecomposition 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 ifThe 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 aluminium is conducted regardless of the pH- dependent speciation in the environment. Hence, as the assessment is based on the element concentration (i.e., Al), 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.

Biotic degradation

For inorganic substance like aluminium salts for which the chemical assessment is based on the elemental concentration (i. e., pooling all inorganic speciation forms together), biotic degradation is an irrelevant process, regardless of the environmental compartment that is under consideration: biotic processes may alter the speciation form of an element, but it will not eliminate the element from the aquatic compartment by degradation or transformation. This elemental-based assessment (pooling all speciation forms together) can be considered as a worst-case assumption for the chemical assessment.

References:

Driscoll CT, Postek KM., 1996, The chemistry of aluminium in surface waters. In: Sposito G., editor, The environmental chenistry of aluminium. 2nd edition. Boca Raton (FL): CRC Press. p: 363-418.

 Exley C. 2003. A biogeochemical cycle for aluminium.Journal of Inorganic Biochemistry97:17.