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Short-term toxicity endpoints are available for freshwater fish, daphnia and algae which cover 3 trophic levels. From the results obtained the freshwater algae Pseudokirchneriella subcapitata emerges as the most sensitive species to the test substance with an ErC50of >0.274 mg/L.

Short-term toxicity to fish

The acute toxicity of dialuminium titanium pentaoxide to medaka (Oryzias latipes) was determined in a study carried out under semi-static conditions in accordance with OECD guideline 203 ''Fish, Acute Toxicity Test''. As the test substance is a poorly soluble inorganic compound, the test organisms were exposed to the test substance dissolved at the maximum saturation level, separated by filtration from a system loaded at a nominal rate of 100 mg/L. Concentrations of dissolved aluminium and titanium were determined by ICP-MS which were then used to calculate equivalent concentrations of the test substance. The test organisms were kept in 5 L aquaria and test solutions were renewed every 24 hours.

After 96 hours of exposure no mortality or abnormal effects were observed. The 96hr LC50of dialuminium titanium pentaoxide was determined to be >0.468 mg/L based on aluminium analysis and >0.360 mg/L based on titanium analysis. All validity criteria were met and this study is considered reliable without restriction.

Short-term toxicity to daphnia

The acute toxicity of dialuminium titanium pentaoxide toDaphnia magnawas determined in a study which was carried out in accordance with OECD guideline 202 ''Daphniasp., Acute Immobilisation Test''. As the test substance is a poorly soluble inorganic compound, test organisms were exposed to the test substance dissolved at the maximum saturation level separated by filtration from a system loaded at a nominal rate of 100 mg/L. Concentrations of dissolved aluminium and titanium were determined by ICP-MS and were then used to calculate equivalent concentrations of the test substance. Test solutions were renewed every 24 hours.

After 48 hours of exposure no immobilisation or abnormal symptoms were observed. The 48hr EC50of dialuminium titanium pentaoxide was determined to be >0.824 mg/L based on aluminium analysis and >0.687 mg/L based on titanium analysis. All validity criteria were met and this study is considered reliable without restriction.

Algal growth inhibition test

The inhibitory effect of dialuminium titanium pentaoxide on algal growth was determined in a 72 hour growth inhibition test withPseudokirchneriella subcapitata, conducted in accordance with OECD guideline 201. The algae were exposed to the test substance at loading rates of 0 (control), 10, 18, 32, 56 and 100 mg/L. Concentrations of dissolved aluminium and titanium were determined by ICP-MS which were then used to calculate equivalent concentrations of the test substance present in the test solutions. Test media were not renewed during the 72 hours.

The 72hr ErC50 based on aluminium analysis was determined to be >0.388 mg/L. The 72hr ErC50 based on titanium analysis was determined to be >0.274 mg/L in the standard growth medium and >0.210 mg/L in the enhanced growth medium. The 72hr NOECr based on titanium analysis was determined to be 0.210 mg/L in enhanced growth medium.

The NOECr for the standard medium occurred at the 10 mg/L loading rate, while the NOEC for the enhanced medium occurred at 100 mg/L. As concentrations of test substance measured were comparable in the 100 mg/L treatments of both the standard and enhanced media, it was suggested that the effect of the test substance in the standard medium was due to decreased bioavailability of nutrients caused by aluminium and titanium forming complexes with components of the test media. This is not considered to be a toxicological effect and as such is not used for derivation of NOEC of endpoints.

No unusual cell shape or agglutination was observed at any test concentration after 72 hours.

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