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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

Neither the silicate part of the molecule (based on data for silicic acid, potassium salt, 215-199-1), nor the zirconium part (based on data for zirconium dichloride oxide, 231-717-9) elicits any environmentally relevant adverse response in aquatic organisms; no PNEC was derived for the aquatic compartment. As a result no PNEC could be derived for the terrestrial compartment. Overall, because of its transformation to insoluble zirconium compounds in the environment, which are not toxic, no chemical safety assessment needs to be performed. Therefore, no refinement of the hazard assessment is required and hence no toxicity testing with terrestrial organisms, including soil micro-organisms is needed.

Key value for chemical safety assessment

Additional information

The substance is the product of a reaction between an inorganic zirconium silicate ore (zircon) with sodium hydroxide. In accordance with column 2 of REACH Annex IX, toxicity testing with terrestrial organisms depends on the outcome of the chemical safety assessment using PNECs derived based on equilibrium partitioning. Neither the silicate part of the molecule (based on data for silicic acid, potassium salt, 215-199-1), nor the zirconium part (based on data for zirconium dichloride oxide, 231-717-9) elicits any environmentally relevant adverse response in aquatic organisms; no PNEC was derived for the aquatic compartment. As a result no PNEC could be derived for the terrestrial compartment. Overall, because of its transformation to insoluble zirconium compounds in the environment, which are not toxic, no chemical safety assessment needs to be performed for silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide. Therefore, no refinement of the hazard assessment is required and hence no toxicity testing with terrestrial organisms, including soil micro-organisms is needed.

The above should be considered as an expert statement to waive the requirement for testing for toxicity to soil micro-organisms under REACH Annex IX for endpoint 9.4.2.