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EC number: 237-523-0 | CAS number: 13825-74-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
The conduct of a study on toxicity to microorganisms with the target substance titanium oxide sulphate itself is being waived, as the substance is highly unstable in water and produces insoluble oxide after rapid hydrolysis. Nevertheless, based on the information available it can be concluded that neither target compound titanium oxide sulphate nor the final hydrolysis transformation products titanium dioxide and sulphuric acid (when being neutralised) ) exhibit toxicity to microorganisms.
Key value for chemical safety assessment
Additional information
The conduct of a study on toxicity to microorganisms with the target substance itself is being waived, as the substance is highly unstable in water and produces insoluble oxide after rapid hydrolysis. Thus the aquatic hazard assessment is to be based on the transformation products. As pH effects are not true toxic effects, they are not primarily relevant for assessment. The recent version of the OECD TGD 209 (2010) recommends “Solutions / suspensions of test substance in water should be neutralised prior to inoculum addition, if necessary. However, since neutralisation may change the chemical properties of the substance, further testing depending on the purposes of the study, could be performed to assess the effect of the test substance on the sludge without pH adjustment”.
As furthermore sulphates are present in high natural background concentrations, the primary assessment shall be based on final hydrolysis products titanium dioxide and sulphuric acid.
In an experiment performed with the hydrolysis product titanium dioxide, Egeler & Goth (2009) loaded the analogue material in a magnitude corresponding to 2002 mg/l of target compound titanium oxide sulphate, without any effect. This suggests that titanium dioxide is not likely to contribute to the overall effect of titanium oxide sulphate.
In order to assess the contribution of acidity to the overall effect, read across from the experiment of Daniels (2008) was made, where the pH effects to activated sludge respiration were studied using hydrochloric acid.
Hydrochloric acid in this case shall be used as source chemical for read across to target chemical sulphuric acid, which in fact is the relevant transformation product for pH effect assessment of target chemical titanium oxide sulphate. Read across is deemed to be applicable as both hydrochloric acid as well as sulphuric acid are strong mineral acids with more or less comparable acidity. There is however one major difference, as hydrochloric acid is a singly protonated acid, whereas sulphuric acid has two protolysis steps. Still it is considered conceivable that the acidity of two-protonated acids can be approximated by considering the first step of protolysis only.
In the experiment of Daniels (2008) hydrochloric acid has been shown to have an inhibitory effect on respiration rates of activated sewage sludge at pH 6.0 to 4.0, with an EC50 at between pH 5.0 and 5.5. By analysis of the dose response curve the EC50 was assigned to pH 5.2. This was normalized to mg/L 0.23 mg/L, which corresponds to 6.3 µmol/L.
As one mol of target substance titanium oxide sulphate results in one mol sulphuric acid, and as only the first protolysis step shall be considered, from above stated hydrolysis reaction results approximately one mol hydronium ions. The EC50of target compound titanium oxide sulphate to activated sludge microorganisms therefore would be assigned to 6.3 µmol/L. Based on the titanium oxide sulphate molecular weight of 159.93 g/mol, this corresponds to a mass concentration of 1.0 mg/L. The result suggests strong pH related effects resulting from the hydrolysis of target compound titanium oxide sulphate.
In conclusion the toxicity of the hydrolysis products of titanium oxide sulphate are considered not toxic to aquatic micro-organisms and no threshold level is derived.
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