Reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance is inorganic

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

According to REACH Regulation, Annex VII, 9.2, column 2, a study on biodegradability does not need to be conducted if the substance is inorganic. Substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is an inorganic crystalline solid of lamellar structure. The concept of “biodegradability” has been developed for organic substances and is not applicable to inorganic substances. Notwithstanding, for running EUSES within the Chesar tool, information on biodegradation and for classification for chronic aquatic effects information on degradation is needed. As a surrogate approach for assessing “degradability” of inorganic substances, the concept of “removal from the water column” has been developed to assess whether or not a respective metal ion, or inorganic substance would remain present in the water column upon addition (and thus, be able to exert a chronic effect) or would be rapidly removed from the water column. In this concept, “rapid removal” (defined as >70 % removal within 28 days) can be considered equivalent to “rapid degradation”. For structurally related substances to substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" - so called nanoclays - the environmental fate has been assessed on behalf of a national authority. In consideration of this assessment, most probably, if released to the environment, the inorganic, sparingly soluble crystalline solid of lamellar clay mineral (hydrocalumite)-like substance will end up in the sediment or soil compartment by sedimentation comparable to natural clay minerals. This fate is not expected to result in any negative environmental impact (c.f. G.E. Batley and M.J. McLaughlin CSIRO Niche Manufacturing Flagship Report, Fate of Manufactured Nanomaterials in the Australian Environment, prepared for the Australian Department of the Environment, Water, Heritage and the Arts (March 2010), available via Internet https://www.environment.gov.au/system/files/pages/371475a0-2195-496d-91b2-0a33f9342a6d/files/manufactured-nanomaterials.pdf). Transformation by normal environmental processes (e.g. diagenesis or dissolution) is not expected to result in any negative environmental impact either, as the substance does only comprise of nonhazardous common environmental elements.

Further on, if dissoluted in water, the dissoluted moieties - calcium, phosphate, aluminium - are not considered to be bioaccumulative, or to be able to exert a chronic effect. Thus, "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is considered as equivalent to being ‘rapidly degradable‘ in the context of classification for chronic aquatic effects and running EUSES within the Chesar tool. To feed this information into Chesar, the respective information must be given in the IUCLID section on biodegradation, although in the proper sense, this section is not applicable to inorganic substances. Thus, for the sake to fill the information on readily degradability into Chesar via IUCLID, ‘ready biodegradability‘ has been selected as key value.