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EC number: 630-337-4
CAS number: 39211-00-2
to the REACH Guidance on information requirements and chemical safety
assessment, a leading DN(M)EL needs to be derived for every relevant
human population and every relevant route, duration and frequency of
exposure, if feasible.
to the REACH guideline (R8, Appendix R 8-8), 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 risk for high peak exposures. The
substance is classified for acute inhalation toxicity. For
short term exposure to cesium tetrafluoroaluminate, a DNEL has been
derived based on the results of an acute inhalation study according to
the REACH guidance.
data are available concerning local effects after repeated dermal
contact with cesium
Based on the read-across from cesium fluoro aluminate complex, the
substance is not considered to be irritating or sensitizing to the skin,
while it is considered to be corrosive for eyes. Therefore,
no local dermal DNELs need to be derived.
The key study for DNEL derivation was
identified as a repeated dose oral study according to OECD 407 (Rijcken
Pels, 1999) where a NOAEL of 30 mg/kg bw/day was derived. The
DNELs for chronic systemic toxicity for the inhalation and dermal route
are derived via route-to-route extrapolation based on the repeated dose
oral toxicity study.
In the absence of substance
specific quantitative data on absorption, 100% absorption is
assumed for the inhalation and 50% for the oral route. For the
dernal route, 1.6% absorption is assumed.
inhalation, systemic effects
inhalation repeated dose toxicity studies with cesium
tetrafluoroalulminate are not available, route to route extrapolation
was applied to derive a DNEL for the inhalation route, based on the
results of an oral 28-day repeated dose study with the read-across
candidate cesium fluoro aluminate complex in rat (Rijcken Pels, 1999)
where an NOAEL of 30 mg/kg bw/day was derived.
Step 1) Relevant dose-descriptor
NOAEL: 30 mg/kg bw/day
Exposure of rats at concentrations up to 30 mg/kg bw/day did not induce clinical abnormalities, differences in food consumption and body weight, and changes in haematology or clinical chemistry parameters. Based on the findings in the stomach, kidneys and spleen in the mid and high dose animals, a dose of 30 mg/kg bw/day was considered as NOAEL.
Step 2) Modification of starting point
0.38 m3/kg bw
The REACH Guidance on information requirements and chemical safety assessment (R.8.4.2) prescribes a default factor of 2 in case of oral to inhalation extrapolation.
Standard respiratory volume of a rat, corrected for 8 h exposure, as proposed in the REACH Guidance on information requirements and chemical safety assessment (R.8.4.2).
30 x (1/0.38) x (1/2) x (6.7/10) = 26.4 mg/m3
Step 3) Assessment factors
No factor for allometric scaling is needed in case of inhalation exposure.A default factor of 2.5 for remaining uncertainties is used.
Default AF for workers
Extrapolation to chronic exposure based on a sub-acute toxicity study
Quality of database
26.4 / (2.5 x 5 x 6 x 1 x 1) = 0.35 mg/m3
– inhalation, systemic effects
Approach according to
Based on the available
acute inhalation toxicity study with cesium tetrafluoroaluminate in rats
(Van Huygevoort, 2013).
NOAEC: 1000 mg/m3
No deaths occurred and no abnormalities were found at macroscopic examination. Therefore, 1000 mg/m3 is interpreted as a NOAEC.
In the REACH guidance (R.8, Appendix R. 8-8), it is mentioned: ‘If a DNEL for acute toxicity needs to be established, this should be derived only for a specified fraction of the daily exposure duration (usually 15 minutes)’. The most appropriate approach is the modified Haber’s law (Cn* t = k). For extrapolation from longer to shorter durations a default value of n=3 should be used.
Correction for activity driven differences of respiratory volumes in workers compared to workers in rest (6.7 m3/10 m3).
For inhalation studies only a factor 2.5 is used, and no correction is made for differences in body size, because extrapolation is based on toxicological equivalence of a concentration of a chemical in the air of experimental animals and humans; animals and humans breathe at a rate depending on their caloric requirements.
Step 4) Calculate DNEL
3√(10003x 16) x (6.7/10) / (2.5 x 5 x 1 x 1 x 1) = 135 mg/m3
dermal repeated dose toxicity studies with cesium tetrafluoroaluminate
are not available, route to route extrapolation was applied to derive a
DNEL for the dermal route, based
on the results of an oral 28-day repeated dose study with the
read-across candidate cesium fluoro aluminate complex in rat (Rijcken
Pels, 1999) where an NOAEL of 30 mg/kg bw/day was derived.
NOAEL: 30 mg/kg bw/day
Exposure of rats at concentrations up to 30 mg/kg bw/day did not induceclinical abnormalities, differences in food consumption and body weight, and changes in haematology or clinical chemistry parameters.Based on the findings in the stomach, kidneys and spleen in the mid and high dose animals, a dose of 30 mg/kg bw/day was considered as NOAEL.
Conversion into dermal NAEL (in mg/kg bw/day) assuming 100% oral absorption and 1.6% dermal absorption for cesium tetrafluoroaluminate.
30 x (100/1.6) = 1875 mg/kg bw/day
4 x 2.5
Assessment factor for allometric scaling and remaining uncertainties.
1875 / (4 x 2.5 x 5 x 6 x 1 x 1) = 6.25 mg/kg bw/day
As there is
no consumer use for cesium tetrafluoroaluminate, no inhalation and
dermal DNELs for the general population were calculated. However, the
deposition of cesium fluoroaluminate in the environment may contribute
to the total cesium and fluoride intake of the general public,
therefore, a long-term oral DNEL for the general population was
calculated. No route-to-route extrapolation had to be performed since
the DNEL has been derived from a NOAEL observed in an oral
28-day repeated dose study with the read-across candidate cesium fluoro
aluminate complex in rat (Rijcken Pels, 1999).
oral, systemic effects (based on sub-acute oral toxicity study with rats)
Default assessment factors for allometric scaling and remaining interspecies differences.
Default assessment factor for general population
Extrapolation to chronic exposure based on a sub-acute toxicity study.
30 / (4 x 2.5 x 10 x 6 x 1 x 1) = 30 / 600 = 0.05 mg/kg bw/day
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