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EC number: 431-620-3
CAS number: -
The DNEL for inhalation exposure for workers is given by the formula:
corrected inhalation NOAEC= NOAEL(oral-rat)* 1/sRVrat * (Absorption
(oral-rat)/Absorption(inhal-human))* (sRVhuman/wRV) Where SRV is the
standard Respiratory Volume and wRV is the worker Respiratory Volume.
The default values assumed for these factors are as follows:
Absorption(oral-rat)=50%; Absorption(inhal-human) =100%; sRVrat=0.38
m3/kg/d; sRVhuman= 6.7m3 (8hr); wRV=10m3(8hr). NOAEC(corrected)= 150
mg/kg bw/day* (1/0.38 m3/kg/d)*(50%/100%)* 6.7m3 (8hr)/ 10m3(8hr)
NOAEC(corrected)= 132.2 mg/m3
ECHA guidance assumes that absorption for dermal exposure is the same as
for oral exposure, which is a worst case assumption.
of Assessment factors for Intra – Inter species variation for workers
(2010) has produced guidance on the assessment factors to use to derive
a DNEL for human exposure based the application of assessment factors
(safety factors) to an NOAEL or LOAEL in animal studies.
ECHA guidance proposes an assessment factor of 4 for the allometric
scaling from rats to humans when calculating oral and dermal DNELs.
However it then proposes an additional factor of 2.5 to cover remaining
differences (uncertainties). There is no clear scientific justification
for this additional factor. ECETOC in itsGuidance on Assessment
Factors to Derive a DNEL(2010) reviewed the scientific evidence and
concluded that the factor of 4 for rats was sufficient to cover the
allometric scaling from rats to humans and any remaining differences are
of intra-species rather than interspecies variability. Based on this,
the additional assessment factor of 2.5 for inter-species variability
will not be used.
ECETOC guidance also reviewed the intra-species assessment factors,
which ECHA proposed as 5 for workers and 10 for the general
population. ECETOC originally proposed in 2003, based on the scientific
evidence, that assessment factors of 3 for workers and 5 for the general
population are sufficient for covering any intra-species variability,
which includes the remaining differences factor of 2.5.
was confirmed in the ECETOC (2010) Guidance.
reviewing these proposals, we have adopted the proposal from ECETOC as
our default assessment factors but consider possible additional factors
on a case by case basis.
this case we have decided to use an assessment factor of 3 for workers
based on the ECETOC Guidance (ECETOC 2010).
2010 Guidance on information requirements and chemical safety assessment
Chapter R.8: Characterisation of dose [concentration]-response for human
health. Version 2 December 2010
2010Guidance on Assessment Factors to Derive a DNEL,Technical
Report No.110,ISSN-0773-8072-110 (print),ISSN-2079-1562-110 (online),
DNELs have been derived for exposure of the general public since the
214702-01 EC 431-620-3 CAS 162537-11-3
a pharmaceutical intermediate and no exposure of the General Population
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