Dichloro(diphenyl)silane

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

9 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):

11

Dose descriptor starting point:

NOAEL

Value:

40 mg/kg bw/day

Modified dose descriptor starting point:

NOAEC

Value:

98.7 mg/m³

Explanation for the modification of the dose descriptor starting point:

The long-term DNEL for systemic effects via the inhalation route is determined on the basis of the 90-day oral NOAEL on the registration substance itself.

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)

= 40 mg/kg bw/day * (1/0.38 m³/kg bw/day) * (1/1) * 0.67 m³ * 1.4= 98.7 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)

AF for dose response relationship:

1

Justification:

The dose descriptor starting point is based on a NOAEL.

AF for differences in duration of exposure:

2

Justification:

based on a subchronic study

AF for interspecies differences (allometric scaling):

1

Justification:

AF not used for inhalation route

AF for other interspecies differences:

2.5

Justification:

ECHA default

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:

high hazard (no threshold derived)

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

27.8 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: Assessment based on the IOEL for hydrochloric acid (8 mg/m3 (8 h TWA) in Commission Directive 2000/39/EC).

Overall assessment factor (AF):

1

Dose descriptor:

other: based on Occupational Exposure Limit (OEL) for HCl (8 h TWA)

Value:

8 mg/m³

AF for dose response relationship:

1

Justification:

Not required as assessment based on OEL.

AF for differences in duration of exposure:

1

Justification:

Not required as assessment based on OEL.

AF for interspecies differences (allometric scaling):

1

Justification:

Not required as assessment based on OEL.

AF for other interspecies differences:

1

Justification:

Not required as assessment based on OEL.

AF for intraspecies differences:

1

Justification:

Not required as assessment based on OEL.

AF for the quality of the whole database:

1

Justification:

Not required as assessment based on OEL.

AF for remaining uncertainties:

1

Justification:

Not required as assessment based on OEL.

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

52.1 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: Based on the ISTEL for HCl

Overall assessment factor (AF):

1

Workers - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

1.27 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):

44

Dose descriptor starting point:

NOAEL

Value:

40 mg/kg bw/day

Modified dose descriptor starting point:

NOAEL

Value:

56 mg/kg bw/day

Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a subchronic repeated dose oral toxicity study (OECD 408; 2020).

Corrected starting point for the dermal route for workers:

Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal) * (7 days exposure rat / 5 days exposure worker) = 40 mg/kg bw/day *(1/1) * (7/5) = 56 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:

2

Justification:

based on a subchronic study

AF for interspecies differences (allometric scaling):

4

Justification:

The experimental animal was a rat.

AF for other interspecies differences:

2.5

Justification:

ECHA default

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:

high hazard (no threshold derived)

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

high hazard (no threshold derived)

Acute/short term exposure

Hazard assessment conclusion:

high hazard (no threshold derived)

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

high hazard (no threshold derived)

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

General Population - Hazard via oral route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected