2-(2-oxo-5-(1,1,3,3-tetramethylbutyl)-2,3-dihydro-1-benzofuran-3-yl)-4-(1,1,3,3-tetramethylbutyl)phenyl acetate

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

3 mg/m³

DNEL related information

DNEL derivation method:

other: The general exposure limit for inhalable dust is applied

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:

8.3 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):

120

Modified dose descriptor starting point:

NOAEL

Value:

1 000 mg/kg bw/day

Explanation for the modification of the dose descriptor starting point:

No data for the dermal route were available; a route to route extrapolation was performed according to ECHA guidance.

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

Identification of relevant dose descriptor

For the derivation of the DNELs, the 28-day repeated dose toxicity study by the oral route in rats was qualified as the most relevant study. The dose descriptor chosen was the NOAEL of 1000 mg/kg/day.

Calculation of DNELs

Systemic, long-term, inhalative

According to"ECHA guidance on information requirements and chemical safety assessment, Chapter R8", the systemic DNEL for the inhalation route is derived by route to route extrapolation if no data for the inhalation exposure is available. Calculation of the DNEL following the method and assessment factors described would result in a DNEL above the general exposure limit for dust. For such cases the ECHA guideline suggests that the general exposure limit shall be applied, especially for non-soluble dusts. For significantly soluble dusts this limit might be relevant as well. The test substance is characterized with low water solubility and no data on absorption after inhalation is available. Therefore toxicological effects related to lung clearance overload (as caused by non-soluble dusts) cannot be ruled out and consequently the general exposure limit for dust is applied. Particle size distribution analysis revealed that a substantial fraction of the test substance is small enough to penetrate into the broncho-alveolar tract. Therefore, the general exposure limit of 3 mg/m³ for inhalable dust is applied.

Systemic, long-term, dermal:

DNEL = NOAEL (oral) / Sum of assessment factors applicable

The dermal route is typically covered by oral route information in the absence of data for this administration route. Since no data on skin penetration is available a worst case approach was chosen and absorption of 100% is assumed. The following assessment factors according to "ECHA guidance on information requirements and chemical safety assessment, Chapter R8" were chosen:

Intraspecies differences (worker): 5

Interspecies variations: 1

Allometric scaling (rat to human): 4

Exposure duration: 6

Dose-response factor: 1

Quality of whole database factor: 1

Overall, an assessment factor of 120 was employed for the dermal route.

DNEL= 1000 mg/kg body weight / 120 = 8.3 mg/kg body weight.

Rationale for omitting "Factor 2.5"

According to ECETOC’s “guidance on Assessment Factors to derive a DNEL, Technical Report No. 110”, the application of a factor of 2.5 for ‘remaining uncertainties’ is unjustified. There is evidence that multiplicative association between inter- and intraspecies assessment factors is overly conservative and that the inclusion of a factor for remaining differences is unnecessary. ECETOC further recommends using allometric scaling and the 5th percentile of the human distribution of intraspecies variability. Consequently, the ‘remaining uncertainty’ for interspecies variability is already accounted for by the intraspecies AF (Calabrese, 1985; Hattis et al 1987). This is further supported by results of the ongoing ERASM project which examines studies in rats and mice to determine interspecies differences based on a probabilistic approach. In their recent publication (Escher, 2013), the authors confirmed the ECETOC position regarding the factor of 2.5 for remaining uncertainties (i. e. the factor does not apply). Therefore, the factor of 2.5 for remaining uncertainties is omitted for this risk assessment.

Literature:

- Calabrese EJ, Uncertainty factors and interindividual variation, Regul Toxicol Pharmacol. 1985 Jun;5(2):190-6.

- Hattis D et al, Human variability in susceptibility to toxic chemicals-a preliminary analysis of pharmacokinetic data from normal volunteers, Risk Anal. 1987 Dec;7(4):415-26.

- Escher SE et al, Interspecies extrapolation based on the RepDose database—A probabilistic approach, Toxicology Letters 218 (2013) 159– 165

Systemic, short-term, dermal and by inhalation

According to the ECHA document "Guidance on information requirements and chemical safety assessment, Chapter R.8: Characterization of dose[concentration]-response for human health", a DNEL for acute systemic toxicity should only be derived if an acute systemic toxicity hazard leading to classification is identified. Therefore, because the substance is not classified for acute toxicity according to Directive 67/548/EEC and Regulation 1272/2008/EC, no systemic DNELs for short-term exposures were calculated.

Local, long-term, by inhalation

Based on the available key toxicological information, the test item is not subject to classification for irritation and sensitization (according to 67/548/EEC and EC/1272/2008). Therefore, no DNEL for local effects is derived. However, to protect against potential lung clearance overload effects related to long term inhalation of low soluble dust particles, the general exposure of limit of 3 mg/m³ for inhalable dust is applied. It is maintained in the section of long term systemic effects.

Local, short-term, by inhalation

Based on the available key toxicological information, the test item is not subject to classification for irritation and sensitization (according to 67/548/EEC and EC/1272/2008). Accordingly, no DNELs for local effects following acute/short-term or long-term exposure are derived. This is in line with the ECHA guidance document (Chapter R.8).

Local, long-term and short-term, dermal

Based on the available key toxicological information, the test item is not subject to classification for irritation and sensitization (according to 67/548/EEC and EC/1272/2008). Accordingly, no DNELs for local effects following acute/short-term or long-term exposure are derived. This is in line with the ECHA guidance document (Chapter R.8).

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:

DNEL (Derived No Effect Level)

Value:

4.2 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):

240

Modified dose descriptor starting point:

NOAEL

Value:

1 000 mg/kg bw/day

Explanation for the modification of the dose descriptor starting point:

Since no data for the dermal route was available, a route to route extrapolation was performed.

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:

4.2 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):

240

Modified dose descriptor starting point:

NOAEL

Value:

1 000 mg/kg bw/day

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

Identification of relevant dose descriptor

The dose descriptor chosen is the same as for workers. The NOAEL of 1000 mg/kg observed in the oral 28-day repeated dose study in rats was used as starting point to derive the DNELs.

Calculation of DNELs

Systemic, long-term, dermal:

DNEL = NOAEL (oral) / Sum of assessment factors applicable

The dermal route is typically covered by oral route information in the absence of data for this administration route. Since no data on skin penetration is available a worst case approach was chosen and absorption of 100% is assumed. The following assessment factors according to "ECHA guidance on information requirements and chemical safety assessment, Chapter R8" were chosen:

Intraspecies differences (worker): 10

Interspecies variations: 1

Allometric scaling (rat to human): 4

Exposure duration: 6

Dose-response factor: 1

Quality of whole database factor: 1

Overall, an assessment factor of 240 was employed for the dermal route.

DNEL= 1000 mg/kg body weight / 240 = 4.2 mg/kg body weight.

Systemic, long-term, oral:

The following assessment factors according to "ECHA guidance on information requirements and chemical safety assessment, Chapter R8" were chosen:

Intraspecies differences (worker): 10

Interspecies variations: 1

Allometric scaling (rat to human): 4

Exposure duration: 6

Dose-response factor: 1

Quality of whole database factor: 1

The overall assessment factor employed for the oral route is therefore 240.

DNEL= 1000 mg/kg body weight / 240 = 4.2 mg/kg body weight.

Factor 2.5 rationale

According to ECETOC’s “guidance on Assessment Factors to derive a DNEL, Technical Report No. 110”, the application of a factor of 2.5 for ‘remaining uncertainties’ is unjustified. There is evidence that multiplicative association between inter- and intraspecies assessment factors is overly conservative and that the inclusion of a factor for remaining differences is unnecessary. ECETOC further recommends using allometric scaling and the 5th percentile of the human distribution of intraspecies variability. Consequently, the ‘remaining uncertainty’ for interspecies variability is already accounted for by the intraspecies AF (Calabrese, 1985; Hattis et al 1987). This is further supported by results of the ongoing ERASM project which examines studies in rats and mice to determine interspecies differences based on a probabilistic approach. In their recent publication (Escher, 2013), the authors confirmed the ECETOC position regarding the factor of 2.5 for remaining uncertainties (i. e. the factor does not apply). Therefore, the factor of 2.5 for remaining uncertainties is omitted for this risk assessment.

Literature:

- Calabrese EJ, Uncertainty factors and interindividual variation, Regul Toxicol Pharmacol. 1985 Jun;5(2):190-6.

- Hattis D et al, Human variability in susceptibility to toxic chemicals-a preliminary analysis of pharmacokinetic data from normal volunteers, Risk Anal. 1987 Dec;7(4):415-26.

- Escher SE et al, Interspecies extrapolation based on the RepDose database—A probabilistic approach, Toxicology Letters 218 (2013) 159– 165

Systemic and Local, short term and long-term, inhalative

The pure, dusty product is neither intended for use by the general population nor are there any possible use scenarios that might be of interest to the general population. The chemical is embedded in polymer and plastic materials at low concentrations. Based on the very low vapor pressure, evaporation from these materials is not possible. Therefore, no inhalative DNELs for the general population need to be derived.

Systemic, short-term, dermal and oral

According to the ECHA document "Guidance on information requirements and chemical safety assessment, Chapter R.8: Characterization of dose[concentration]-response for human health", a DNEL for acute systemic toxicity should only be derived if an acute systemic toxicity hazard leading to classification is identified. Therefore, because the substance is not classified for acute toxicity according to Directive 67/548/EEC and Regulation 1272/2008/EC, no systemic DNELs for short-term exposures were calculated.

Local, long-term and short-term, dermal

Based on the available key toxicological information, the test item is not subject to classification for skin and eye irritation and skin sensitization (according to 67/548/EEC and EC/1272/2008). Accordingly, no DNELs for local effects following acute/short-term or long-term exposure are derived. This is in line with the ECHA guidance document (Chapter R.8).