Titanium tetraisopropanolate

Endpoint summary

Additional information

Titanium tetrapropanolate is hydrolytically unstable with the half-life < 3 minutes determined by OECD 111. In this study, the progress of the hydrolysis was followed by monitoring isopropyl alcohol (IPA), the main degradation product of the substance. Recoveries of IPA were used to evaluate the hydrolytic stability of the substance. The other non-hazardous degradation product (hydrated titanium oxide) is insoluble lacking bioavailablity in aquatic environment, and therefore not further considered in CSA.

Because of the rapid hydrolysis of this substance, the intrinsic properties of aquatic toxicity are related to the main degradation product (IPA) of this substance. This was also demonstrated in the aquatic toxicity key studies (Daphnia and algae) conducted for this substance. Due to the rapid hydrolysis in aqueous test media, the degradation products (IPA and hydrated titanium dioxides) toxicity to the freshwater invertebrates and algae were investigated based on the measured IPA concentrations and the equivalent test item concentrations.

Based on the toxicity test results conducted for the substance, the short-term and long-term aquatic toxicity to other organisms (fish and micro-organisms) was considered scientifically unjustified and the supporting read-across data from the main degradation product (IPA) was used as a key value in CSA.

Short-term toxicity to fish:

• 96-h LC50 (mortality) to Rasbora heteromorpha, 4200 mg/L based on nominal concentrations (read-across from IPA; Tooby & Hursey 1975)

Short term toxicity to invertebrates:

• 48-hour EC50 (immobilisation) to Daphnia magna, 590 mg IPA/l (95 % CI, 570 to 610 mg IPA/l) based on the measured (0-hour) concentrations. (OECD 202; Goodband 2010)
• 48-hour EC50 (immobilisation) to Daphnia magna, 700 mg/l (95% Cl, 680 to 720 mg/l based on the equivalent test item concentrations (OECD 202; Goodband 2010)

Toxicity to algae:

• The 72h-EC50 (growth rate) to Desmodesmus subspicatus, >820 mg /l based on measured IPA concentrations (OECD 201; Vryenhoef & Mullee 2010)
• The 72h-NOEC (growth rate) to Desmodesmus subspicatus, 201 mg /l based on measured IPA concentrations (OECD 201; Vryenhoef & Mullee 2010)
• The 72h-EC50 (growth rate) to Desmodesmus subspicatus, >960 mg /l based on equivalent test item concentrations (OECD 201; Vryenhoef & Mullee 2010)
• The 72h-NOEC (growth rate) to Desmodesmus subspicatus, 237 mg /l based on equivalent test item concentrations (OECD 201; Vryenhoef & Mullee 2010)

Toxicity to micro-organisms:

• 16-h toxicity threshold to Pseudomonas putida (cell multiplication); 1050 mg/l, based on the nominal concentrations (read-across from IPA, Bringmann & Kuhn 1980)