Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Titanium carbide was not tested for terrestrial toxicity and read-across to titanium dioxide and titanium trichloride was used for these endpoints.

For titanium substances, the read-across strategy is predicated on the assumed presence and bioavailability of a common metal anion in environmental media after exposure to titanium compounds. This is a reasonable assumption for the majority of inorganic compounds.

 

For environmental endpoints, it is the relative mobility and resulting bioavailability in various environmental compartments that determines the potential toxicity to ecological receptors. In the absence of data for titanium carbide, the most simplistic and conservative approach to hazard evaluation, using the read-across strategy, is to assume that titanium carbide which is to be evaluated shows the same systemic hazards as titanium dioxide and TiCl3, which show a higher release of titanium ions compared to titanium carbide (T/D test, solubility below the detection limit of 0.4 µg/L). (Bioelution results (KMHC, 2012) are in this case of minor relevance as earthworms and woodlice digest food by enzymatic degradation during gut passage without influence of gastric fluids.)

 

Titanium dioxide is not toxic to soil macroorganisms: Bulk titanium dioxide was not toxic to Eisenia fetida in an earthworm reproduction test (OECD 222) at a concentration of 1000 mg/kg soil dw, and no effects were noted in a feeding study with Porcellio scaber at concentrations up to 3000 mg TiO2/kg food. 

 

Relevant key studies for the endpoints toxicity to terrestrial plants and toxicity to terrestrial microorganisms are not available. However, additional testing is not required for both endpoints. In accordance with REACH Annex IX, 9.4, column 2, the equilibrium partitioning method (EPM) based on aquatic data may be applied to assess the hazard to soil organisms in the absence of reliable toxicity data for soil microorganisms and terrestrial plants. However, since no hazard was identified for aquatic organisms, consequently no hazard is identified for terrestrial organisms via EPM. In addition, the available key studies on earthworms and soil arthropods do not indicate toxic effects for soil organisms. Furthermore, the results of the T/D test indicate that Ti need not be expected to be bioavailable in the soil matrix.