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Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
5.87 mg/m³
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
150
Dose descriptor starting point:
NOAEL
Value:
1 000 mg/kg bw/day
Modified dose descriptor starting point:
NOAEC
Value:
881 mg/m³
Explanation for the modification of the dose descriptor starting point:

A modification of the dose dsecrptior starting point (oral to inhalation) was conducted. It is assumed as a worst case assumption that the oral absorption rate is 50% of that of the inhalation absorption.

The corrected dose descriptor (NOAEC) for inhalation was calculated in accordance with the ECHA Guidance on information requirements and chemical safety assessment, Chapter R.8: Characterisation of dose [concentration]-response for human health.

The conversion of an oral rat NOAEL into a corrected inhalatory NOAEC to assess human inhalatory exposure was performed using the modification of starting point equation as given in Figure R. 8-3 (see below) for workers (in the case of 8 hour exposure/day).

Default parameters for rats and humans (for 8 hour exposure) were used for the modification of starting point under the allometric scaling principle as given in Table R. 8-2 of the above ECHA guidance.

Conversion of an oral rate N(L)OAEL into a correct inhalatory N(L)OAEC to assess human inhalatory exposure:

For workers (in case of 8h exposure/day):

Corrected inhalatory N(L)OAEC = oral N(L)OAEL x (1 / sRVrat) x (ABSoral-rat / ABSinh-human) x (sRVhuman / wRV)

Corrected inhalatory N(L)OAEC= 1000 mg/kg bw/day x (1 / 0.38 m3/kg/d) x (0.5) x (6.7 m3(8h) / 10 m3(8h)) = 881 mg/m3

Where:

ABS: Absorption

sRV: standard Respiratory Volume

wRV: worker Respiratory Volume (light activity)

Default parametrs:

sRVrat (8 h): 0.38m3/kg bw

sRVhuman (8 h): 6.7 m3/ person

wRV (8 h): 10 m3/ person

AF for dose response relationship:
1
Justification:
When the starting point for the DNEL calculation is a NOAEL the default assessment factor is 1.
AF for differences in duration of exposure:
6
Justification:
Default for subacute to chronic studies (OECD 422 study assessed as subacute study as most conservative value)
AF for interspecies differences (allometric scaling):
1
Justification:
AF for allometric scaling not required as the differences in allometry (respiration rate and rate to human body sizes) were considered in the conversion from oral to inhalation starting point.
AF for other interspecies differences:
2.5
Justification:
Default AF for remaining interspecies differences.
AF for intraspecies differences:
5
Justification:
Default AF for worker population
AF for the quality of the whole database:
1
Justification:
Quality of data considered to be reliable.
AF for remaining uncertainties:
2
Justification:
An additional AF of 2 has been applied as the OECD 422 study (providing the repeat dose toxicity data) has been read-across from a structurally similar analogue substance. An additional AF has been considered applicable based on any minor potential differences between the substances.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information
Explanation for the modification of the dose descriptor starting point:

No acute inhalation study has been conducted so no results are available to derive an acute inhalation DNEL for systemic effects.

Inhalation is not considered to be a significant route of exposure for workers based on the substance being of low volatility and use patterns (see inhalation data waivers for details).

An acute DNEL for acute systemic effects is therefore not considered to be necessary.

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:
1.67 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
600
Dose descriptor starting point:
NOAEL
Value:
1 000 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
Value:
1 000 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

It is considered that dermal absorption will not be higher than oral absorption, therefore no default factor (i. e. factor 1) should be introduced when performing oral-to dermal extrapolation.

AF for dose response relationship:
1
Justification:
When the starting point for the DNEL calculation is a NOAEL the default assessment factor is 1.
AF for differences in duration of exposure:
6
Justification:
Default for subacute to chronic studies (OECD 422 study assessed as subacute study as most conservative value)
AF for interspecies differences (allometric scaling):
4
Justification:
Default AF for allometric scaling based on rats
AF for other interspecies differences:
2.5
Justification:
Default AF for remaining interspecies differences.
AF for intraspecies differences:
5
Justification:
Default AF for worker population.
AF for the quality of the whole database:
1
Justification:
Quality of data considered to be reliable.
AF for remaining uncertainties:
2
Justification:
An additional AF of 2 has been applied as the OECD 422 study (providing the repeat dose toxicity data) has been read-across from a structurally similar analogue substance. An additional AF has been considered applicable based on any minor potential differences between the substances.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)
Acute/short term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
sensitisation (skin)

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - workers

DNEL for long-term systemic effects have been derived for both inhalation and dermal routes, based on the results of an OECD 422 study on a structural analogue substance. The NOAEL in this study was 1000 mg/kg bw/day (the top dose tested) but DNELs have been derived as a worst case assessment.

Inhalation is also not considered to be a significant route of exposure.

The substance is a skin sensitiser (moderate hazard) and local dermal effects will be assessed in a qualitative assessment.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
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:
no hazard identified
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:
no hazard identified
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

DNEL values have not be calculated for the general population/consumers, as the substance will not be made available to the general public and there is no potential for exposure to the substance for consumers. The substance is consumed during the polymerisation process into contact lens material. Once polymerised, there is no degradation. Under normal conditions of use, the substance is not leached out of the finished product.