Registration Dossier
Registration Dossier
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 201-739-3 | CAS number: 87-32-1
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data

Toxicological Summary
- Administrative data
- Workers - Hazard via inhalation route
- Workers - Hazard via dermal route
- Workers - Hazard for the eyes
- Additional information - workers
- General Population - Hazard via inhalation route
- General Population - Hazard via dermal route
- General Population - Hazard via oral route
- General Population - Hazard for the eyes
- Additional information - General Population
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 411.4 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:
- 2 500 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 61 710 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 developmental toxicity study in rats with the source substance (N-acetyl-L-tryptophan) (Kadota, 1980).
To take into account the interspecies difference between the rat and human the no observed adverse effect level (NOAEL) 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) * (days of exposure per week in rats / days of exposure per week worker)
= 2500 mg/kg bw/day * (1/0.38 m³/kg bw/day) * (1/0.1) * 0.67 m³ * (7/5) = 61710 mg/m³.
(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)
The inhalation absorption is assumed to be 10% based on granulometry data, which shows, D10: 14.1 µm, that a very low fraction of the particles are likely to reach the alveoli of the lungs. The D50: 94.0 µm and the D90: 292.7 µm, indicating that a fraction of the particles may be inhaled and are likely to be deposited before reaching the alveolar region. Particles deposited in the nasopharyngeal/thoracic region will mainly be cleared from the airways by the mucocilliary mechanism and swallowed or coughed out.
Therefore, the corrected starting point for workers was 61710 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 (10-day) study
- AF for interspecies differences (allometric scaling):
- 1
- Justification:
- AF not used for the inhalation route
- AF for other interspecies differences:
- 2.5
- Justification:
- Default value
- AF for intraspecies differences:
- 5
- Justification:
- Default value for workers according to ECHA REACh Guidance
- AF for the quality of the whole database:
- 2
- Justification:
- The DNEL is based on a study with some limitations
- 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:
- 41.7 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:
- 2 500 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEL
- Value:
- 25 000 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 developmental toxicity study in rats with the source substance (N-acetyl-L-tryptophan) (Kadota, 1980).
Corrected starting point for the dermal route for workers:
Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal)
= 2500 mg/kg bw/day * (1/0.1) = 25000 mg/kg bw/day.
The dermal absorption potential is assumed to be 10%, based on the prediction of low dermal absorption potential (please refer to the toxicokinetic statement).
- 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 (10-day) study
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- Default AF for rats
- AF for other interspecies differences:
- 2.5
- Justification:
- Default value
- AF for intraspecies differences:
- 5
- Justification:
- Default value for workers
- AF for the quality of the whole database:
- 2
- Justification:
- The DNEL is based on a study with some limitations
- 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:
- hazard unknown but no further hazard information necessary as no exposure expected
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
General Population - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 72.5 µg/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):
- 300
- Dose descriptor starting point:
- NOAEL
- Value:
- 2 500 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 21 739.1 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 developmental toxicity study in rats with the source substance (N-Acetyl-L-tryptophan) (Kadota, 1980).
To take into account the interspecies difference between the rat and human the no observed adverse effect level (NOAEL) has to be corrected as follows:
Corrected starting point for the inhalative route for the general population:
= NOAEL(oral) * (1/1.15 m³/kg bw/day) * (ABSoral-rat/ABSinh-human)
= 2500 mg/kg bw/day * (1/1.15 m³/kg bw/day) * (1/0.1) = 21739.1 mg/m³
(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)
The inhalation absorption is assumed to be 10% based on granulometry data, which shows, D10: 14.1 µm, that a very low fraction of the particles are likely to reach the alveoli of the lungs. The D50: 94.0 µm and the D90: 292.7 µm, indicating that a fraction of the particles may be inhaled and are likely to be deposited before reaching the alveolar region. Particles deposited in the nasopharyngeal/thoracic region will mainly be cleared from the airways by the mucocilliary mechanism and swallowed or coughed out.
The corrected starting point for workers was 21739.1 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 (10-day) study
- AF for interspecies differences (allometric scaling):
- 1
- Justification:
- AF not used for the inhalation route
- AF for other interspecies differences:
- 2.5
- Justification:
- Default AF
- AF for intraspecies differences:
- 10
- Justification:
- Default AF for general population
- AF for the quality of the whole database:
- 2
- Justification:
- The DNEL is based on a study with some limitations
- 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:
- 20.8 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):
- 1 200
- Dose descriptor starting point:
- NOAEL
- Value:
- 2 500 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEL
- Value:
- 25 000 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 developmental toxicity study in rats with the source substance (N-acetyl-L-tryptophan) (Kadota, 1980).
Corrected starting point for the dermal route for the general population:
Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal)
= 2500 mg/kg bw/day * (1/0.1) = 25000 mg/kg bw/day.
The dermal absorption potential is assumed to be 10%, based on the prediction of low dermal absorption potential (please refer to the toxicokinetik statement).
- 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:
- Default AF for rats
- AF for other interspecies differences:
- 2.5
- Justification:
- Default AF
- AF for intraspecies differences:
- 10
- Justification:
- Default AF for general population
- AF for the quality of the whole database:
- 2
- Justification:
- The DNEL is based on a study with some limitations
- 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:
- hazard unknown but no further hazard information necessary as no exposure expected
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:
- 2.08 mg/kg bw/day
- Most sensitive endpoint:
- developmental toxicity / teratogenicity
- Route of original study:
- Oral
DNEL related information
- DNEL derivation method:
- ECHA REACH Guidance
- Overall assessment factor (AF):
- 1 200
- Dose descriptor starting point:
- NOAEL
- Value:
- 2 500 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
No route-to-route extrapolation necessary.
- 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:
- Default AF for rats
- AF for other interspecies differences:
- 2.5
- Justification:
- Default AF
- AF for intraspecies differences:
- 10
- Justification:
- Default AF for general population
- AF for the quality of the whole database:
- 2
- Justification:
- The DNEL is based on a study with some limitations
- AF for remaining uncertainties:
- 1
- Justification:
- No remaining uncertainties
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
General Population - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- no hazard identified
Additional information - General Population
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
