Titanium dioxide

CHEMICAL SUBSTANCE IDENTIFICATION

Chemical name                 

Titanium dioxide

Synonyms                           

anatase, anatase titanium dioxide, brookite, nano-anatase, nano-TiO2, rutile, Titania, titanium dioxide, titanium oxide, titanium white[2]

Natural titanium dioxide exists in nature in one of three crystalline forms, the two most important of which are anatase  and rutile , the third being brookite. Rutile is the thermodynamically stable form of titanium dioxide; anatase rapidly transforms to rutile above 700°C. [1]

IUPAC name

dioxotitanium [2]

CAS No

13463-67-7[1] 

1317-70-0 (anatase) [1]

1317-80-2 (rutile) [1]

12188-41-9 (brookite) [1]

REACH registration number

Fully registered

EC No

Molecular formula              

TiO2 or O2Ti  [2]

Substance group/chemical family

monoconstituent substance/inorganic  [1]

Appearance

Physical state

Odour

 Form

     Colour

solid at 20°C and 1013 hPa

odourless

crystalline

white

USES AND HANDLING ISSUES

Relevant identified uses

Handling considerations

Handling: Avoid raising and breathing dust. Observe good industrial hygiene practice for chemical handling.
Technical Measures: Avoid raising dust. Handling systems and areas should be operated in such a way as to minimise exposure to dust. 
Precautions: Local exhaust ventilation may be necessary. Handle minimising dust. Take precautionary measures against static discharges.
Advice on usage: Manual handling guidelines should be adhered to when handling sacks.
Storage conditions: Pigments should not be stored in outside areas exposed to the weather. Care should be taken to avoid exposure to moisture. [1]

PHYSICO-CHEMICAL PROPERTIES

Molecular weight                                  

79.865 g/mol

Bulk density/Specific gravity

3.9 - 4.17 g/cm³ @ 20 °C [1]

3.9 (anatase), 4.26 (rutile), 4.17 (brookite) [1]

pH

 7  [1]

Particle size

Pigmentary titanium dioxide is composed of primary particles with a mean particle size typically in the range 0.2 to 0.3 microns in diameter.

Nano titanium dioxide is composed of primary particles which are <100 nm in size. These primary particles naturally form aggregates and agglomerates which are above 100 nm. [1]

EC

Melting point

1560°C (anatase), 1843°C (rutile), 1825°C (brookite) [1]

Boiling point

2 500 - 3 000 °C @ 101.3 - 101.325 kPa [1]

Flash point

the flash point is only relevant to liquids and low melting point solids [1]

Flammability

 the substance does not react with water, e.g. the substance is manufactured with water or washed with water [1]

Vapour density

Vapour pressure

study scientifically not necessary because the melting point is above 300°C  [1]

Solubility in water

1 µg/L @ 20 °C and pH 6 [1]

micro- and nano-forms of TiO2 do not dissolve to any relevant extent under regular environmental conditions. Thus, dissolution is not important for the environmental fate and behaviour of nano-and micro-sized TiO2 in environmental compartments. [1]

Solubility in organic solvents

insoluble [1]

Solubility in inorganic solvents

insoluble [8]

soluble in alkalis, dissolves slowly in hydrofluoric acid and in hot concentrated sulphuric acid. [2]

insoluble in hydrochloric acid, nitric acid or diluted sulfuric acid  [2].

Hydrolysis

Ionicity in water

Surface tension

based on structure, surface activity is not expected or cannot be predicted  because water solubility is below 1 mg/L at 20°C [1]

Dispersion properties

Explosiveness

there are no chemical groups present in the molecule which are associated with explosive properties

Stability and reactivity

Chemical stability

Stable under normal conditions. [1]

Reactivity hazards

Corrosivity

Polimerization

Incompatibility with various substances

Special remarks on reactivity

the substance is incapable of reacting exothermically with combustible materials [1]

Physical, chemical and biological coefficient

Koc

Kow

pKa

log Kp

Henry-constant

ENVIRONMENTAL FATE AND BEHAVIOUR

Artificial pollution sources

TiO₂ production and use as a pigment, welding-rod-coating materials, as ceramic colorant, as source of titanium metal. As color in the food industry; manufacture of acid resistant vitreous enamels, in specification paints, exterior white house paints, acetate rayon, white interior air-dry and baked enamels and lacquers, inks and plastics, for paper filling and coating, in water paints, tanners' leather finishes, shoe whiteners, and ceramics and as a pharmaceutic aid (coating agent). [1]

General terrestrial fate

General aquatic fate

General atmospheric fate

General persistence and degradability

Abiotic degradation and metabolites

Biodegradation and metabolites

Biodegradation is an irrelevant process for inorganic substances that are assessed on an elemental basis, including titanium dioxide. [1]

Bioconcentration

Volatilization

Photolysis

Hydrolysis

Soil adsorption and mobility

ENVIRONMENTAL CONCENTRATIONS

Measured data

Typical baseline concentrations for titanium in various environmental compartments as derived from monitoring data are summarised according to [1]:

Background stream water dissolved/dispersed Ti 4.21 µg/L
Background stream water sediment  Ti 0.81%
Background topsoil Ti 0.663 %
Background subsoil  Ti 0.645 %
Agricultural soil Ti 0.603 %
Grazing land soil Ti 0.607 % 

ECOTOXICOLOGICAL INFORMATION

General adverse effects on ecosystem

Acute toxicity (LC50, EC50)

Aquatic systems

 Micro-and nanosized TiO2 is not acutely and chronically toxic to aquatic organisms. Thus, nano- and microsized TiO2 are not a classified or non-classified acute and chronic hazard to aquatic organisms. [1]

LC50 (14 days) 870 - 1 100 µg/L (fish) [1]

LC50 (48 h) 500 mg/L (aquatic invertebrates) [1]

EC50 (72 h) 100 mg/L (aquatic algae and cyanobacteria) [1]

EC50 (7 days) 100 mg/L (aquatic plants other than algae) [1]

EC50 (3 h) 1 g/L (microorganisms) [1]

Terrestrial systems

Toxicity data from standard toxicity tests indicate that micro-and nanosized TiO2 materials are not toxic to soil organisms including microbes, plants and invertebrates up to at least 1000 mg/kg dw soil. [1]

Chronic toxicity (NOEC, LOEC)

Aquatic systems

Micro-and nanosized TiO2 is not acutely and chronically toxic to aquatic organisms. Thus, nano- and microsized TiO2 are not a classified or non-classified acute and chronic hazard to aquatic organisms. [1]

NOEC (14 days) 870 - 1 100 µg/L (fish) [1]

NOEC (28 days) 100 mg/L (aquatic invertabrates) [1]

NOEC (21 days) 1.72 - 5 mg/L (aquatic invertabrates) [1]

LOEC (21 days) 5 mg/L (aquatic invertabrates) [1]

NOEC (32 days) 1 mg/L (aquatic algae and cyanobacteria) [1]

NOEC (72 h) 100 mg/L (aquatic algae and cyanobacteria) [1]

NOEC (3 h) 1 g/L (microorganisms) [1]

LOEC (3 h) 1 g/L (microorganisms) [1]

NOEC (28 days) 1 000 mg/kg sediment dw [1]

NOEC (28 days) 100 mg/L [1]

LOEC (28 days) 1 000 mg/kg sediment dw  [1]

Terrestrial systems

Toxicity data from standard toxicity tests indicate that micro-and nanosized TiO2 materials are not toxic to soil organisms including microbes, plants and invertebrates up to at least 1000 mg/kg dw soil. [1]

NOEC (56 days) 400 - 1 000 mg/kg soil dw (macroorgnisms except arthropodes) [1]

NOEC (28 days) 400 - 1 000 mg/kg soil dw  (macroorgnisms except arthropodes) [1]

NOEC (14 days) 1 g/kg soil dw  (macroorgnisms except arthropodes) [1]

NOEC (84 days) 1 g/kg soil dw (terrestrial plants) [1]

NOEC (14 days) 44 - 100 mg/kg soil dw (terrestrial plants) [1]

LOEC (14 days) 67 - 100 mg/kg soil dw (terrestrial plants) [1]

NOEC (28 days) 21 - 100 mg/kg soil dw ( soil microorganisms) [1]

HUMAN HEALTH EFFECTS and PROTECTION

Routes of human exposures

 oral, inhalation, dermal [1]

Occupational exposure to titanium dioxide may occur through inhalation and dermal contact at workplaces where titanium dioxide is produced or used. The general population may be exposed to titanium dioxide via inhalation, ingestion, and dermal contact with consumer products containing titanium dioxide [1, 3]

General effects

Endocrine disruption

Mutagenicity

Carcinogenicity

Proposed hazard classification advocated by the French Agency for Food, Environmental and Occupational Health & Safety, ANSES [4]:

Category 2 (Animal) carcinogen by inhalation [1]

Reprotoxicity

No adverse effect observed NOAEL 1 000 mg/kg bw/day (subchronic, rat) (oral) [1]

Teratogenicity

Skin, eye and respiratory irritations

No adverse effect observed [1]

Titanium dioxide does not show respiratory sensitising properties in animal studies or in exposure related observations in humans. [1]

Metabolism:

absorption, distribution & excretion

Exposure limits

Drinking water MAC

Other information

The Scientific Committee on Consumer Safety (SCCS) [8] has described the genotoxic, carcinogenic, and photosensitization behaviour of TiO2 nanoparticles (NPs) (SCCS/1516/13), and several in vitro and in vivo studies have shown the adverse effects of TiO2 NPs in biological systems [5, 6, 7, 8]

Animal toxicity data

Acute toxicity (LD50)

LD50 2 000 - 25 000 mg/kg bw (rat) oral [1]

LD50 5 000 mg/kg bw (mouse) oral [1]

LC50 (4 h) 3.43 - 6.82 mg/L air (rat) (inhalation) [1]

Chronic toxicity (NOEL, LOEL)

ENVIRONMENTAL STANDARDS AND REGULATIONS

EINECS regulation

̵Listed

OSHA regulations etc.

OSHA Occupational Exposure Hazard:

Permissible Exposure Limit: 8-hr Time Weighted Avg: 15 mg/m3. /Total dust/

OSHA  Threshold Limit Values:

8 hr Time Weighted Avg (TWA): 10 mg/m3.

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.

Not classifiable as a human carcinogen [3]

OTHER INFORMATION, SPECIAL REMARKS

Classification and proposed labelling with regard to toxicological data

NIOSH Recommendations: NIOSH considers titanium dioxide to be a potential occupational carcinogen. NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration. NIOSH considers titanium dioxide to be a potential occupational carcinogen (5000 mg/m3)

Warning! According to the classification provided by companies to ECHA in REACH registrations this substance is suspected of causing cancer. [1]

CREATED, LAST UPDATE

Created

2019. 04. 15

Last update

2019. 04. 16

REFERENCES

 [1] ECHA, European Chemical Agency, Titanium dioxide,  https://echa.europa.eu/hu/registration-dossier/-/registered-dossier/15560/1 2019.04.15,  https://echa.europa.eu/hu/brief-profile/-/briefprofile/100.033.327,  Accessed: 2019.04.15-04.16

[2] PubCHem, Titanium dioxide (compound) https://pubchem.ncbi.nlm.nih.gov/compound/titanium_dioxide#section=Depositor-Supplied-Synonyms,  Accessed: 2019.04.15

[3] Toxnet, HSDB: Titanium Dioxide https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+@rel+13463-67-7,  Accessed: 2019.04.15

[4]ESMA, Titanium dioxide: The classification debate (2018)  https://www.esma.com/news/dot-news/hsep/887-titanium-dioxide-the-classification-debate  Accessed: 2019.04.16

[5] Iavicoli I., Leso V., Fontana L., Bergamaschi A. (2011) Toxicological effects of titanium dioxide nanoparticles: a review of in vitro mammalian studies. European Review for Medical and Pharmacological Sciences. 15(5):481–508. 

[6] Iavicoli I., Leso V., Bergamaschi A. (2012) Toxicological effects of titanium dioxide nanoparticles: a review of in vivo studies. Journal of Nanomaterials., 36. doi: 10.1155/2012/964381.964381

[7] Syed Niaz Ali Shah, Zahir Shah, Muzammal Hussain, Muzaffar Khan (2017) Hazardous Effects of Titanium Dioxide Nanoparticles in Ecosystem, Bioinorg Chem Appl.,  2017: 4101735., PMCID: PMC5360948, doi: 10.1155/2017/4101735

[8] SCCS (Scientific Committee on Consumer Safety), Opinion on 56 titanium dioxide (nano form), 22 July 2013, revision of 22 April 2014. Doi: 10.2772/70108, Accessed: 2019.04.16