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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
11.2 mg/m³
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
other: substance-specific (for further details please refer to discussion section)
Overall assessment factor (AF):
33
Dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Modified dose descriptor starting point:
NOAEC
Value:
370 mg/m³
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a combined repeated dose oral toxicity study with the reproduction/developmental toxicity screening test (OECD 422; 2019).

To correct the interspecies difference between rat and human the no observed effect level has to be corrected as follows:

Corrected starting point for the inhalative route for workers:

= NOAEL(oral) * (1/0.38 m³/kg bw/day) * (ABSoral-rat/ABSinh-human) * 6.7 m³ (8h) /10 m³ (8h)* (7 days exposure rat/5 days exposure worker)

= 150 mg/kg bw/day * (1/0.38 m³/kg bw/day) * (1/1) * 0.67 m³ * 1.4 = 370 mg/m³

In contrast to the recommendations of the ECHA Guidance, a factor of 1 (equal absorption of 100% assumed for the oral and the inhalative route for animals and humans) was included for the extrapolation from oral to inhalation absorption, as there is no valid data suggesting that inhalation leads to higher absorption than oral ingestion (recommendation of the VCI Working group "Toxicology", 2008). Molecules with a molecular weight <500 and a log Kow between 0 and 4 can be assumed to be well absorbed equivalently by the oral and inhalation route. Oral absorption may be reduced for acids and bases depending on their pKa value and their electric charge in the GI tract. More lipophilic substances may be better absorbed in the GI tract due to solubilisation with bile acids, and thus oral absorption may be higher than inhalation absorption (VCI Working group "Toxicology", 2008). Unless valid data suggest that inhalation leads to higher absorption than oral ingestion, equal absorption will be assumed when extrapolating from oral to inhalation route.

(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)

Thus, the corrected starting point for workers was 370 mg/m³ for inhalation.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
6
Justification:
The DNEL is based on a subacute study.
AF for interspecies differences (allometric scaling):
1
Justification:
AF is not used for inhalation route.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
2.2
Justification:
substance-specific (for further details please refer to the discussion section)
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
1.6 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
other: substance-specific (for further details please refer to the discussion section)
Overall assessment factor (AF):
132
Dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
Value:
210 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal) * (7 days exposure rat/5 days exposure worker) = 150 mg/kg bw/day *(1/1) * 1.4 = 210 mg/kg bw/day.

It is assumed that oral and dermal absorption rates are equal.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
6
Justification:
The DNEL is based on a subacute study.
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was rat.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
2.2
Justification:
substance-specific (for further details please refer to the discussion section)
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - workers

Assessment factor for intraspecies differences

The intraspecies assessment factor accounts for the variability in sensitivity between individuals. The human population is far more diverse than experimental animals that are bred to be as similar as possible, and unhealthy animals are not allowed to start the study. This AF also covers differences between ethnic groups and age groups. The default intraspecies factors are typically broken down into equal factors accounting for toxicodynamic and toxicokinetic differences, respectively. Accordingly, an interspecies factor of 10 is composed of two identical factors of √10 = 3.2.

Likewise, the default for workers (AF = 5) can be split into AFs of √5 = 2.2. As discussed in the TK assessment, the conversion of silanes to silanols and their excretion proceeds without enzymatic involvement. Individual genetic dispositions and other factors affecting xenobiotic-metabolizing enzymes are therefore without effect on these processes. As a result, the toxicokinetic components (3.2 and 2.2 for general population and workers, respectively) can be eliminated from the intraspecies AF for substances that hydrolyse fast into the ultimate excretion product.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
2.7 mg/m³
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
other: substance-specific (for further details please refer to the discussion section)
Overall assessment factor (AF):
150
Dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Modified dose descriptor starting point:
NOAEC
Value:
130.4 mg/m³
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed from a combined repeated dose oral study with the reproduction/developmental toxicity screening test (OECD 422) in rats.

To correct the interspecies difference between rat and human the no observed effect level has to be corrected as follows:

Corrected starting point for the inhalative route for general population:

= NOAELoral * (1/1.15 m³/kg bw/day (24h)) * (ABSoral-rat / ABSinh-human)

= 150 mg/kg bw/day * (1/1.15 m³/kg bw/day) * (1/1) = 130.4 mg/m³

In contrast to the recommendations of the ECHA Guidance, a factor of 1 (equal absorption of 100% assumed for the oral and the inhalative route for animals and humans) was included for the extrapolation from oral to inhalation absorption, as there is no valid data suggesting that inhalation leads to higher absorption than oral ingestion (recommendation of the VCI Working group "Toxicology", 2008). Molecules with a molecular weight <500 and a log Kow between 0 and 4 can be assumed to be well absorbed equivalently by the oral and inhalation route. Oral absorption may be reduced for acids and bases depending on their pKa value and their electric charge in the GI tract. More lipophilic substances may be better absorbed in the GI tract due to solubilisation with bile acids, and thus oral absorption may be higher than inhalation absorption (VCI Working group "Toxicology", 2008). Unless valid data suggest that inhalation leads to higher absorption than oral ingestion, equal absorption will be assumed when extrapolating from oral to inhalation route.

(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)

Thus, the corrected starting point for general population was 130.4 mg/m³ for inhalation.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
6
Justification:
The DNEL is based on a subacute study.
AF for interspecies differences (allometric scaling):
1
Justification:
AF not used for inhalation route.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
3.2
Justification:
substance-specific (for further details please refer to the discussion section)
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.78 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
other: substance-specific (for further details please refer to the discussion section)
Overall assessment factor (AF):
192
Dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal) = 150 mg/kg bw/day *(1/1) = 150 mg/kg bw/day.

It is assumed that oral and dermal absorption rates are equal.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
6
Justification:
The DNEL is based on a subacute study.
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was rat.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
3.2
Justification:
substance-specific (for further details please refer to the discussion section)
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.78 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
other: substance-specific (for further details please refer to the discussion section)
Overall assessment factor (AF):
192
Dose descriptor starting point:
NOAEL
Value:
150 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

No route-to-route extrapolation required.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
6
Justification:
The DNEL is based on a subacute study.
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was rat.
AF for other interspecies differences:
2.5
Justification:
Default vaulue according to ECHA REACH Guidance.
AF for intraspecies differences:
3.2
Justification:
substance-specific (for further details please refer to the discussion section)
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - General Population