Titanium dioxide

Nanomaterial dustiness

Administrative data

Endpoint:

nanomaterial dustiness

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-11-16 to 2020-12-03

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Reference 2

Reference Type:

publication

Title:

Harmonised classification and labelling of titanium dioxide (TiO₂) - Content of particles with aerodynamic diameter ≤ 10 μm - Methods and results of analysis

Author:

TDMA

Year:

2021

Bibliographic source:

www.tdma.info

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EN 15051-2 (Workplace exposure. Measurement of the dustiness of bulk materials - Rotating drum method)

Deviations:

not specified

GLP compliance:

no

Type of method:

rotating cylinder

Sampling:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Titanium dioxide

EC Number:

236-675-5

EC Name:

Titanium dioxide

Cas Number:

13463-67-7

Molecular formula:

O2Ti

IUPAC Name:

dioxotitanium

Test material form:

solid: nanoform

Details on test material:

All information below taken from: TDMA (2022) Analytical Report on Samples studied in TDMA Grouping Hypothesis testing. TDMA1072

Details on test material:

Sample ID: G6-3
Coating: coated with Al-oxide and hydrophobic organic

SSA: 70 m²/g
skeletal density: 2.796 g/cm³
VSSA: 195.7 m²/cm³
pH (1wt% in deionised water): 6.2
isoelectric point (pH): 7.5
agglomerate density: 1.35 g/cm³

Crystal phase (XRD): 100% rutile

population d50 (SEM, ISO 19749): 9.2 ±2.0
% below 100 nm (SEM, ISO 19749): 100
shape (SEM, ISO 19749): Spindle
aspect ratio (SEM, ISO 19749): 3.24

Chemical Composition, Quantitative bulk chemical analysis (ICP-MS, ASTM D5291):
Sample ID P Al SiO2 C S Cl W
ppm % % % ppm ppm ppm
G6-3 <100 3.57 0.021 7.3 <300 <300 <100

The following elements were analysed but were not detected at levels above the detection limit (100ppm except F and Br 300ppm) :
As, Ag, Au, Be, Ba, Bi, Br, Cd, Co, Cr, Cu, F, Ga, Ge, Hf, Hg, In, Li, Mn, Mo, Ni, Pb, Re, Sb, S, Sn, Sr, Ta, Te, Th, V, Zn.


Inorganic surface composition analysed by X-Ray Photoelectron Spectroscopy (XPS), organic surface treatments identified using 1H and 13C solid state NMR:
Sample ID C O Ti Si Al K Na Nb Zr N P S Cl W
at% at% at% at% at% at% at% at% at% at% at% at% at% at%
G6-3 68.1 22.7 5.85 ND 3.2 ND 0.01 ND ND ND 0.12 0.09 ND
ND = Not detected

Results and discussion

Dustiness index

Dustiness index 1

Key result

Mean:

0.38 other: % wt

Remarks on result:

other: content of particles with aerodynamic diameter <= 10µm

Dustiness index 2

Mean:

< 10 mg/kg

Remarks on result:

other: Respirable dustiness

Dustiness index 3

Mean:

3 836 mg/kg

Remarks on result:

other: Thoracic dustiness

Dustiness index 4

Mean:

8 386 mg/kg

Remarks on result:

other: Inhalable dustiness

Any other information on results incl. tables

TDMA (2021):

The percent particles below 10 μm aerodynamic diameter using `EN 15051-2 - Measurement of the dustiness of bulk materials - Part 2: Rotating drum method´ are taken from the thoracic mass fraction collected from the 80 pore per inch metal foam and filter. The dustiness result is normally expressed in mg/kg and therefore it is converted to % wt. by dividing by 10 000 in line with the text of the classification of TiO2:

The content of particles with aerodynamic diameter ≤ 10 μm for the sample G6-3 is 0.38 % wt (determined by the rotating drum method according to EN 15051-2).

 

Brown (2020)

Category of Dustiness (classified by the EN15051-2 test method):

- Inhalable dustiness mass fraction [mg/kg]: very low < 300; low 300 – 650; moderate 650 – 3000; high > 3000

- Thoracic dustiness mass fraction [mg/kg]: very low < 80; low 80 – 300; moderate 300 – 1000; high > 1000

- Respirable dustiness mass fraction [mg/kg]: very low < 10; low 10 – 60; moderate 60 – 210; high > 210

Dustiness of the test item G6-3 (triplicate analysis):

- Average material weight charged to the drum: 11.66 g for 35 cm³

- Inhalable dustiness: high (8386 mg/kg)

- Thoracic dustiness: high (3836 mg/kg)

- Respirable dustiness: very low (<10 mg/kg)

Applicant's summary and conclusion

Conclusions:

The test item G6-3 has a high (8386 mg/kg) inhalable dustiness, a high (3836 mg/kg) thoracic dustiness and a very low (<10 mg/kg) respirable dustiness.

The content of particles with aerodynamic diameter ≤ 10 μm for the sample G6-3 was 0.38 % wt (EN 15051-2). On the basis of the classification criteria for titanium dioxide (Regulation (EC) 2020/217), this titanium dioxide nano form does not require a classification as a category 2 carcinogen. For further details please refer to the attached analysis report in the endpoint summary for nanomaterial dustiness (IUCLID section 4.28.8).