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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:
1.86 mg/m³
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
75
Modified dose descriptor starting point:
NOAEC
Acute/short term exposure
Hazard assessment conclusion:
hazard unknown (no further information necessary)
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:
0.26 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
300
Modified dose descriptor starting point:
NOAEL
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

For acute effects, no significant effects that would justify DNEL derivation were observed in the corresponding toxicity studies.

For systemic effects, DNEL derivation was performed following the method proposed in the ECHA Guidance on information requirements and chemical safety assessment, Chapter R.8.

1. Long term exposure-systemic toxicity

1.1 Inhalation DNEL(workers)

 Occupational exposure to 11 -aminoundecanoic acid may occur mainly by inhalation of particles, therefore we consider the inhalation route as the most relevant for DNEL derivation.

Of all repeated dose toxicity studies in rats, the OECD TG 421 (reproductive/developmental screening) study (CIT, 2008) is selected for DNEL derivation as it is the study where the lowest NOAEL was observed among the repeated dose toxicity studies data set with 11-aminoundecanoic acid, and because effects on kidneys, considered as the critical effect with a threshold mode of action, were also observed in this study.

 

  • Step 1: Selection of the relevant dose descriptor:

*NOAEL (parental toxicity) = 1250 ppm, equivalent to79 mg/kg/day

*No reproductive effects but renal effects were observed in the parents (histopathological findings).

  • Step 2: Modification of the starting point:

*Conversion into an inhalatory rat NOAEC by dividing by 0.38 m3/kg (8-hour respiratory volume in the rat)

*No correction for inhalatory and oral absorption rates (considered to be 100 % because 11-aminoundecanoic acid is well       absorbed by both routes)

*Correction for activity driven differences in respiratory volume in workers compared to individuals at rest (6.7 m3/10 m3)

*Corrected dose descriptor:NOAEC (worker, 8 h)= 79 x 1/0.38 x 6.7/10 = 139 mg/m3

  • Step 3: Assessment factors:

*Interspecies : no allometric scaling factor is applied because an oral-to-inhalation route extrapolation is performed. However, a factor of 2.5 to correct for differences other than differences in metabolic rate is applied.

*Intraspecies : the default assessment factor of 5 is applied.

* Differences in exposure duration: as the exposure in rats was 54 days, a factor of 6 for subacute-to-chronic extrapolation is applied.

*Dose-response relationship: a factor of 1 is applied due to the use of a NOAEL as dose descriptor and the low toxicity of the test substance.

*Quality of whole database: a factor of 1 is applied based on the good quality of the whole database.

*Global assessment factor: 2.5 x 5 x 6 x 1 x 1 = 75

  • Step 4: DNEL derivation:

 Worker DNEL (long term, systemic effects)= 79 x 1/0.38 x 6.7/10 x 1/75 = 1.86 mg/m3

 

2. Dermal DNEL (workers)

Occupational exposure to 11 -aminoundecanoic acid may also occur by dermal exposure. Although no dermal repeated dose toxicity studies is available as well as no information on dermal absorption, we derived a dermal DNEL based on the Oral NOAEL selected for the derivation of the inhalation DNEL.

Step 1) Relevant dose-descriptor          

* NOAEL, rats= (parental toxicity) =1250 ppm, equivalent to79 mg/kg/day

Step 2)Modification of starting point:

* Correction for oral to dermal absorption :

11 -aminoundecanoic acid has a low octanol partition coefficient (log Kow=0.16) which predicts a low dermal absorption. However as no dermal penetration study is available we consider 100% absorbsion as a worst case (=1).

No difference in dermal absorption is expected between rats and humans, no correction factor will be applied.

Step 3) Assessment factors

* Interspecies: 2.5 x 4

* Intraspecies : 5

* Exposure duration : 6 (as the exposure in rats was 54 days, a factor of 6 for subacute-to-chronic extrapolation is applied).

* Dose response:1

* Quality of database:1

DNEL Value based on NOAEL 28-d/rabbits :

79 x 1 x 1/(2.5 x 4 x 5 x 6 x 1 x 1) = 0.26 mg/kg bw

Oral route

 

The oral route of exposure is not relevant to workers.

General Population - Hazard via inhalation route

Systemic effects

Acute/short term exposure
DNEL related information

Local effects

Acute/short term exposure
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Acute/short term exposure
DNEL related information

General Population - Hazard via oral route

Systemic effects

Acute/short term exposure
DNEL related information

General Population - Hazard for the eyes

Additional information - General Population

Occupational exposure to 11 -aminoundecanoic acid is the most relevant potential safety concern under the conditions of use of the substance. There is no direct consumer use of 11 -aminoundecanoic acid, Food contact materials made of polyamide 11 contain low residual levels of 11-aminoundecanoic acid (<100 ppm) and are subject to very strict regulations, therefore no DNEL derivation for general population was deemed necessary.