Iron titanium pseudobrookite

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

particle size distribution (granulometry)

Remarks:

dustiness

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Heubach-Dust-Meter connected to a cascade impactor

Qualifier:

according to guideline

Guideline:

DIN 55992-1 (Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method)

Version / remarks:

2006

Deviations:

yes

Remarks:

Heubach-dust-meter connected to a cascade impactor

Principles of method if other than guideline:

The Heubach dust meter is modified in a way that a seven stage cascade impactor is connected to the system. This involves an additional air fed of 20 L/min via the coarse dust separator needed to supply the cascade impactor with 40 L/min air current as specified in the manufacturer’s specificcations.

The calculation report: Grewe, T (2016)

The Multiple-Path Particle Dosimetry Model (MPPD, v2.11; ARA, 2009) was used to predict this fractional deposition behaviour for workers.
The model algorithms calculate the deposition (and clearance) of mono-disperse and polydisperse aerosols in the respiratory tract for particles ranging from ultra-fine (0.01 microns) to coarse (20 microns) sizes. Within each airway, deposition is calculated using theoretically derived efficiencies for deposition by diffusion, sedimentation and impaction within the airway or airway bifurcation. Filtration of aerosols by the head is determined using empirical efficiency functions.

GLP compliance:

no

Type of method:

other: Heubach-dust-meter connected to a cascade impactor

Type of distribution:

volumetric distribution

Mass median aerodynamic diameter:

47.41 µm

Geometric standard deviation:

2.22

Remarks on result:

not measured/tested

Remarks on result:

not measured/tested

Total dustiness (airborne fraction): 20.63 mg/g.

In the original study report by DMT, a calculation of the mass median diameter was not conducted. Since the deposited fractions were provided for each of the cascade impactor stages, it was possible to fit a lognormal distribution to the data by non-linear regression procedure. As a result, the MMAD and GSD are calculable and reported (MMAD= 47.41 µm, GSD= 2.22).

As the cascade impactor already takes aerodynamic characteristics of the particles into account, the reported mass median diameter can be interpreted as the mass median aerodynamic diameter.

This figure and the corresponding GSD were used as distribution parameters for the MPPD model enabling an estimation of deposited dust fractions in the human respiratory tract: These fractions were estimated as follows:

Head (ET): 30.21 %

Tracheobronchial (TB): 0.08 %

Pulmonary (PU): 0.05 %

Conclusions:

Total Dustiness (airborne fraction): 20.63 mg/g.

Mass median aerodynamic diamater of airborne fraction: MMAD= 47.41 µm, GSD= 2.22

Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):
Head (ET): 30.21 %
Tracheobronchial (TB): 0.08 %
Pulmonary (PU): 0.05 %

Reference 2

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)

Deviations:

not specified

GLP compliance:

no

Type of method:

Laser scattering/diffraction

Type of distribution:

volumetric distribution

Remarks on result:

not measured/tested

Percentile:

D10

Mean:

0.4 µm

Remarks on result:

other: No St. dev. was stated

Key result

Percentile:

D50

Mean:

1 µm

Remarks on result:

other: No St. dev. was stated

Percentile:

D90

Mean:

3.1 µm

Remarks on result:

other: No St. dev. was stated

The parameters d₉₀, d₅₀ and d₁₀ are the cut off particle size below which 90 %, 50 % and 10 % of the total particle volume lies. The parameter d_v and d_s are respectively the volume mean diameter and the surface area mean diameter.

All values are calculated assuming that the particles are spherical.

d₉₀= 3.1 µm

d₅₀= 1.0 µm

d₁₀= 0.4 µm

d_v= 1.7 µm

d_s= 0.8 µm

Conclusions:

The test item has following particle size distribution:
d90= 3.1 µm
d50= 1.0 µm
d10= 0.4 µm

Description of key information

Particle size distribution determind by laser scattering/diffraction (Mestre Beltrán, 2015)

d90= 3.1 µm

d50= 1.0 µm

d10= 0.4 µm

Dustiness determined by a Heubach-dust-meter connected to a cascade impactor (Gogilan, EBRC, 2016)

- total dustiness (airborne fraction): 20.63 mg/g.

- MMAD= 47.41 µm

- GSD= 2.22

Fractional deposition in human respiratory tract (MPPD model, based on calculated MMAD):

- Head (ET): 30.21 %

- Tracheobronchial (TB): 0.08 %

- Pulmonary (PU): 0.05 %