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EC number: 266-340-9
CAS number: 66402-68-4
This category encompasses the various chemical substances manufactured in the production of ceramics. For purposes of this category, a ceramic is defined as a crystalline or partially crystalline, inorganic, non-metallic, usually opaque substance consisting principally of combinations of inorganic oxides of aluminum, calcium, chromium, iron, magnesium, silicon, titanium, or zirconium which conventionally is formed first by fusion or sintering at very high temperatures, then by cooling, generally resulting in a rigid, brittle monophase or multiphase structure. (Those ceramics which are produced by heating inorganic glass, thereby changing its physical structure from amorphous to crystalline but not its chemical identity are not included in this definition.) This category consists of chemical substances other than by-products or impurities which are formed during the production of various ceramics and concurrently incorporated into a ceramic mixture. Its composition may contain any one or a combination of these substances. Trace amounts of oxides and other substances may be present. The following representative elements are principally present as oxides but may also be present as borides, carbides, chlorides, fluorides, nitrides, silicides, or sulfides in multiple oxidation states, or in more complex compounds.@Aluminum@Lithium@Barium@Magnesium@Beryllium@Manganese@Boron@Phosphorus@Cadmium@Potassium@Calcium@Silicon@Carbon@Sodium@Cerium@Thorium@Cesium@Tin@Chromium@Titanium@Cobalt@Uranium@Copper@Yttrium@Hafnium@Zinc@Iron@Zirconium
study for dose descriptor
et al. (1973) is considered the most adequate study from which to obtain
a dose descriptor for a DNEL for repeated dose toxicity (inhalation,
local effect) for aluminium oxide. The NOAEC from Gross et al. (1973), a
chronic study, is 70 mg/m³. No alveolar proteinosis or endogenous lipid
pneumonitis was observed. Alveoli were filled with dust-filled but
otherwise “well-preserved” macrophages, septal walls were not thickened,
there was no evidence of stromal proliferation, and no fibrosis was
found in the lungs or lymph nodes.
et al. (1973)
Test substance: Aluminium
oxide, mean diameter 0.8 µm
used: 0, 30, 70 mg/m³
of exposure in the experiment: 6
(for 70 mg/m³) and 12 months (for 30 mg/m³); 6 hours per day, 5 days per
week; follow-up to 30 months.
macrophages; no alveolar proteinosis, endogenous lipid pneumonitis or
on the weight of evidence, the target substances behave as low
cytotoxic, poorly soluble particulates (PSPs). From a risk assessment
perspective based on studies in rats, two possible thresholds can be
envisioned for pulmonary toxic effects on chronic exposure to ‘nuisance”
dosimetric threshold to avoid overloading macrophages and leading to a
persistent inflammatory response;
mechanistic threshold greater than the dosimetric threshold that occurs
when anti-inflammatory responses are overwhelmed and effects may
progress to fibrosis (Oberdorster, 2002).
persistent inflammatory response potentially leading to fibrosis, the
mode of action for aluminium oxide (dust), aluminium hydroxide and
aluminium powder (uncoated) in the respirable and inhalable size range
is threshold and related to volumetric overloading of macrophages.
of DNEL according the ECHA guidance (ECHA guidance, Chapter R8, p27):
of starting point to correct for differences in inhalation volume
between the rats and lightly active humans –
NOAEC * 6.7m³ (8h)/10m³ (8h)
70 * 6.7/10
46.9 mg/m³; corrected starting point
scaling is not necessary as the mode of action is a portal-of-entry
effect (overload) and adjustment for inhalatory volume has been carried
out to modify the starting point; scientific evidence suggests rats are
at greater susceptibility to overload than humans (Oberdorster, 1995;
Pauluhn, 2010), therefore a factor of 2.5 for remaining effects was not
has adopted the ECETOC (2010) approach for intraspecies and interspecies
assessment factors. Therefore, the client indicated that this value
should be inserted here
of exposure: 1
duration of exposure was adequate.
response extrapolation: 1 (Based
on a NOAEC)
of database: 1
study assessed only histopathological effects and did not look at
sensitive effects such as inflammatory markers in the BALF. However, the
evidence for the lack of fibrogenic effects of Al2O3dust
is also supported by consistent results from intratracheal instillation
studies and the inhalation studies of Christie et al. (1963) and Pigott
et al. (1981). An AF of 1 is considered appropriate.
assessment factor = 3
aluminium oxide = 46.9/3 = 15.63 mg/m³, respirable, 8 hour TWA for Al2O3
the weight of evidence supports the low cytotoxic and low fibrogenic
nature of aluminium oxide and the calculated DNEL is higher than the
general dust limits used in setting Occupational Exposure Limits,the
general dust limits are considered appropriate for exposure scenarios
for aluminium oxide dust.
aluminium oxide = 3 mg/m³, respirable, 8 hour TWA
Summary DNEL derivation:
to REACH guidance (ECHA, 2008, Chapter 8, p.106), there is no generally
accepted methodology for the establishment of an acute toxicity DNEL for
effects occurring after a single exposure of a few minutes up to 24
most cases it may be unnecessary to derive an acute DNEL, as the
long-term DNEL is usually sufficient to ensure that these effects do not
occur. In summary, according to ECHA, a DNEL for acute toxicity should
be derived if an acute toxicity hazard (leading to C&L) has been
identified and there is a potential for high peak exposures, for
example, connecting or disconnecting vessels.
weight of evidence suggests that these substances behave as poorly
soluble low cytotoxicity particulates. A chemical-specific acute
toxicity hazard leading to C&L was not identified for the target
substances. The long-term DNEL should ensure that these effects do not
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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