Registration Dossier
Registration Dossier
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EC number: 231-142-3 | CAS number: 7440-32-6
Toxicological Summary
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Acute/short term exposure
DNEL related information
Local effects
Acute/short term exposure
DNEL related information
Workers - Hazard via dermal route
Systemic effects
Acute/short term exposure
DNEL related information
Workers - Hazard for the eyes
Additional information - workers
Please refer to the report attached in IUCLID section 7 for further information.
Titanium is a transition-metal and is subject at its surface to passivation by the formation of a passive and protective oxide (i. e. titanium dioxide) coating that effectively protects it from further reaction. In particular for titanium metal and granules, the oxide layer will form a quantitatively continuous layer to envelop the entire particle irrespective of product form. The reaction kinetics have been investigated and reported in various references (Uhlig, 1979; Schmets et al. 1953; Andreeva, 1964; Burleigh, 1989; El Din et al., 1988), indicating that the oxide layer is formed immediately after the interaction of the clean surface with the air atmosphere. Any melt processing of titanium metal has to be conducted under an inert atmosphere or vacuum to protect the metal from instant oxidation. Similarly the use of solid titanium at elevated temperatures is restricted due to its propensity for rapid oxidation.
Furthermore, transformation/dissolution testing according to “OECD 29 Environmental Health and Safety Publications, Series on testing and assessment, Guidance document on transformation/ dissolution of metals and metal compounds in Aqueous media” has shown that titanium metal compared to titanium dioxide has a similar release rate of titanium ions (please refer to the respective entry under the endpoint water solubility).
In view of this, it may be assumed that human exposure towards titanium metal is secondary to that of titanium dioxide.
Thus, unlimited read-across for the hazard assessment is considered justified.
References
H.H. Uhlig (1979) Passivity in Metals and Alloys, Corrosion Science, Vol. 19, pp. 777-791
J. Schmets and M. Pourbaix (1953) Equilibrium Potential-pH Diagram for the System Ti-H2O, Corrosion of Titanium, Technical Report RT. 4, CEBELCOR, pp. 167-179
V.V. Andreeva (1964) Behavior and Nature of Thin Oxide Films on Some Metals in Gaseous Media and in Electrolyte Solutions, Corrosion, Vol. 20, No. 2, pp. 35-47
T.D. Burleigh (1989) Anodic Photocurrents and Corrosion Currents on Passive and Active-Passive Metals, Corrosion, Vol. 45, No. 6, pp.464-472
A.M. Shams El Din and A.A. Hammoud (1988) Oxide Film Formation and Thickening on Titanium in Water", Thin Solid Films, Vol. 167, No. 1, pp. 269-280
General Population - Hazard via inhalation route
Systemic effects
Acute/short term exposure
DNEL related information
Local effects
Acute/short term exposure
DNEL related information
General Population - Hazard via dermal route
Systemic effects
Acute/short term exposure
DNEL related information
General Population - Hazard via oral route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 350 mg/kg bw/day
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 10
- Modified dose descriptor starting point:
- NOAEL
Acute/short term exposure
DNEL related information
General Population - Hazard for the eyes
Additional information - General Population
Please refer to the report attached in IUCLID section 7 for further information.
Titanium is a transition-metal and is subject at its surface to passivation by the formation of a passive and protective oxide (i. e. titanium dioxide) coating that effectively protects it from further reaction. In particular for titanium metal and granules, the oxide layer will form a quantitatively continuous layer to envelop the entire particle irrespective of product form. The reaction kinetics have been investigated and reported in various references (Uhlig, 1979; Schmets et al. 1953; Andreeva, 1964; Burleigh, 1989; El Din et al., 1988), indicating that the oxide layer is formed immediately after the interaction of the clean surface with the air atmosphere. Any melt processing of titanium metal has to be conducted under an inert atmosphere or vacuum to protect the metal from instant oxidation. Similarly the use of solid titanium at elevated temperatures is restricted due to its propensity for rapid oxidation.
Furthermore, transformation/dissolution testing according to “OECD 29 Environmental Health and Safety Publications, Series on testing and assessment, Guidance document on transformation/ dissolution of metals and metal compounds in Aqueous media” has shown that titanium metal compared to titanium dioxide has a similar release rate of titanium ions (please refer to the respective entry under the endpoint water solubility).
In view of this, it may be assumed that human exposure towards titanium metal is secondary to that of titanium dioxide.
Thus, unlimited read-across for the hazard assessment is considered justified.
References
H.H. Uhlig (1979) Passivity in Metals and Alloys, Corrosion Science, Vol. 19, pp. 777-791
J. Schmets and M. Pourbaix (1953) Equilibrium Potential-pH Diagram for the System Ti-H2O, Corrosion of Titanium, Technical Report RT. 4, CEBELCOR, pp. 167-179
V.V. Andreeva (1964) Behavior and Nature of Thin Oxide Films on Some Metals in Gaseous Media and in Electrolyte Solutions, Corrosion, Vol. 20, No. 2, pp. 35-47
T.D. Burleigh (1989) Anodic Photocurrents and Corrosion Currents on Passive and Active-Passive Metals, Corrosion, Vol. 45, No. 6, pp.464-472
A.M. Shams El Din and A.A. Hammoud (1988) Oxide Film Formation and Thickening on Titanium in Water", Thin Solid Films, Vol. 167, No. 1, pp. 269-280
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