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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
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EC number: 200-735-9 | CAS number: 70-47-3
- 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:
- 81.4 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):
- 25
- Dose descriptor starting point:
- NOAEL
- Value:
- 1 650 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 2 035.23 mg/m³
- Explanation for the modification of the dose descriptor starting point:
Long term inhalation studies are not available. The long term systemic DNEL for inhalation has been derived from the oral subchronic repeated dose toxicity study. For derivation of the dose descriptor starting point a factor of 2 has been included for route-to-route extrapolation from oral to inhalative.
- AF for dose response relationship:
- 1
- Justification:
- Default ECHA AF for NOAEL used as starting point. The original NOAEL is reliable. No adjustment is required.
- AF for differences in duration of exposure:
- 2
- Justification:
- Default assessment factor for extrapolation from subchronic to chronic
- AF for interspecies differences (allometric scaling):
- 1
- Justification:
- Default corrections for respiratory rate and respiratory volume have been included in route-to-route extrapolation
- AF for other interspecies differences:
- 2.5
- Justification:
- Default assessment factor for remaining differences
- AF for intraspecies differences:
- 5
- Justification:
- Default assessment factor for intraspecies differences
- AF for the quality of the whole database:
- 1
- Justification:
- The key study was conducted according to modern regulatory standards and was adequately reported. On this basis the quality of the database is not considered to contribute uncertainty and it is therefore not necessary to apply an additional factor.
- AF for remaining uncertainties:
- 1
- Justification:
- Based on reliable and relevant data for the test item no remaining uncertainties are expected.
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:
- 80.61 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):
- 100
- Dose descriptor starting point:
- NOAEL
- Value:
- 1 650 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEL
- Value:
- 2 015.23 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
Long term studies with dermal exposure are not available. The long term systemic DNEL for dermal exposure has been derived from the oral subchronic repeated dose toxicity study.
- AF for dose response relationship:
- 1
- Justification:
- Default ECHA AF for NOAEL used as starting point. The original NOAEL is reliable. No adjustment is required.
- AF for differences in duration of exposure:
- 2
- Justification:
- Default assessment factor for extrapolation from subchronic to chronic
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- Allometric scaling rat to humans AF 4 (ECHA 2008).
- AF for other interspecies differences:
- 2.5
- Justification:
- Default assessment factor for remaining differences.
- AF for intraspecies differences:
- 5
- Justification:
- Default assessment factor for intraspecies differences.
- AF for the quality of the whole database:
- 1
- Justification:
- The key study was conducted according to modern regulatory standards and was adequately reported. On this basis the quality of the database is not considered to contribute uncertainty and it is therefore not necessary to apply an additional factor.
- AF for remaining uncertainties:
- 1
- Justification:
- Based on reliable and relevant data for the test item no remaining uncertainties are expected.
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
Selection of the relevant dose descriptors:
Oral:
NOAEL =1650 mg/kg bw/day: subchronic repeated dose toxicity study, rat, oral (gavage)
Modification of the relevant dose descriptors to the correct starting point:
Oral absorption
The physicochemical properties of L-asparagine (log Kow = -3.82) and the molecular weight of 132.1179 g/mol are in a range suggestive of absorption from the gastro-intestinal tract subsequent to oral ingestion (molecular weight < 200 g/mol, log Kow between < -1).
For chemical safety assessment an oral absorption rate of 50 % is assumed as a worst case default value in the absence of other data
Dermal absorption
In the absence of detailed dermal penetration data it has to be assumed that dermal penetration may occur.
For chemical safety assessment a dermal absorption rate of 50 % is assumed as a worst case default value.
Inhalation absorption
For chemical safety assessment an inhalation absorption rate of 100% is assumed as a worst case default value due to lack of reliable data. Thus, twice as high absorption is assumed compared to oral absorption (Guidance on Information Requirements and Chemical Safety Assessment, R8).
Extrapolation oral to inhalation: AF 2
DERIVATION OF DNELs
DNELs derived from subchronic repeated dose toxicity NOAEL (OECD guideline 408)
Worker-DNEL long-term for inhalation route (systemic): 80.61 mg/m³
Start value: 1650 mg/kg bw/d
Route of original study: oral
Dose descriptor starting point after route-to-route extrapolation: 2015.23 mg/m³
For workers the corrected inhalation NOEC is calculated according to the following equation:
corrected inhalation NOAEC = oral NOAEL x 1/sRVrat x ABSoral-rat/ ABSinh-human x sRVhuman/ wRV
= 1650 x 1/0.384 x 50/100 x 6.7/10
In order to implement a correction for the differences between human and experimental exposure conditions as recommended by ECHA Guidance R.8 (version 2.1, November 2012), the NOEC was corrected for by a factor of 1.4 for the workers population:
Experimental exposure conditions:
From oral studies: 7 days/week
Human exposure conditions (workers):
Exposure via oral route: 5 days /week
7days/5 days = 1.4
The corrected inhalation NOAECworker (8h) is therefore:
= 2015.23 mg/m³ (8h-TWA)
Overall AF: 1*2*1*2.5*5*1 = 25
This DNEL does not address the potential for local irritation. The risk characterisation will consider whether specific risk management measures are necessary to protect against local effects.
Worker-DNEL long-term for dermal route (systemic): 23.10 mg/kg bw/d
Start value: 1650 mg/kg bw/d
Route of original study: oral
Dose descriptor starting point after route-to-route extrapolation: 2310 mg/kg bw/d
Overall AF: 1*2*4*2.5*5*1 = 100
General Population - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 12.2 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):
- 50
- Dose descriptor starting point:
- NOAEL
- Value:
- 1 650 mg/kg bw/day
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 611.11 mg/m³
- Explanation for the modification of the dose descriptor starting point:
Long term inhalation studies are not available. The long term systemic DNEL for inhalation has been derived from the oral subchronic repeated dose toxicity study. For derivation of the dose descriptor starting point a factor of 2 has been included for route-to-route extrapolation from oral to inhalative.
- AF for dose response relationship:
- 1
- Justification:
- Default (DNEL calculator)
- AF for differences in duration of exposure:
- 2
- Justification:
- Default (DNEL calculator)
- AF for interspecies differences (allometric scaling):
- 1
- Justification:
- Default (DNEL calculator)
- AF for other interspecies differences:
- 2.5
- Justification:
- Default (DNEL calculator)
- AF for intraspecies differences:
- 10
- Justification:
- Default (DNEL calculator)
- AF for the quality of the whole database:
- 1
- Justification:
- Default (DNEL calculator)
- AF for remaining uncertainties:
- 1
- Justification:
- Based on reliable and relevant data for the test item no remaining uncertainties are expected.
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:
- 8.25 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):
- 200
- Dose descriptor starting point:
- NOAEL
- Value:
- 1 650 mg/kg bw/day
- Value:
- 1 650 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
Long term studies with dermal exposure are not available. The long term systemic DNEL for dermal exposure has been derived from the oral subchronic repeated dose toxicity study.
- AF for dose response relationship:
- 1
- Justification:
- Default (DNEL calculator)
- AF for differences in duration of exposure:
- 2
- Justification:
- Default (DNEL calculator)
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- Default (DNEL calculator)
- AF for other interspecies differences:
- 2.5
- Justification:
- Default (DNEL calculator)
- AF for intraspecies differences:
- 10
- Justification:
- Default (DNEL calculator)
- AF for the quality of the whole database:
- 1
- Justification:
- Default (DNEL calculator)
- AF for remaining uncertainties:
- 1
- Justification:
- Based on reliable and relevant data for the test item no remaining uncertainties are expected.
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:
- 8.25 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):
- 200
- Dose descriptor starting point:
- NOAEL
- Value:
- 1 650 mg/kg bw/day
- Value:
- 1 650 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
The long term systemic DNEL for oral exposure has been derived from the oral subchronic repeated dose toxicity study.
- AF for dose response relationship:
- 1
- Justification:
- Default (DNEL calculator)
- AF for differences in duration of exposure:
- 2
- Justification:
- Default (DNEL calculator)
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- Default (DNEL calculator)
- AF for other interspecies differences:
- 2.5
- Justification:
- Default (DNEL calculator)
- AF for intraspecies differences:
- 10
- Justification:
- Default (DNEL calculator)
- AF for the quality of the whole database:
- 1
- Justification:
- Default (DNEL calculator)
- AF for remaining uncertainties:
- 1
- Justification:
- Based on reliable and relevant data for the test item no remaining uncertainties are expected.
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
Selection of the relevant dose descriptors:
Oral:
NOAEL =1650 mg/kg bw/day: subchronic repeated dose toxicity study, rat, oral (gavage); OECD 408
Modification of the relevant dose descriptors to the correct starting point:
Oral absorption
The physicochemical properties of L-asparagine (log Kow = -3.82) and the molecular weight of 132.1179 g/mol are in a range suggestive of absorption from the gastro-intestinal tract subsequent to oral ingestion (molecular weight < 200 g/mol, log Kow between < -1).
For chemical safety assessment an oral absorption rate of 50% is assumed as a worst case default value in the absence of other data.
Dermal absorption
In the absence of detailed dermal penetration data it has to be assumed that dermal penetration may occur.
For chemical safety assessment a dermal absorption rate of 50% is assumed as a worst case default value.
Inhalation absorption
For chemical safety assessment an inhalation absorption rate of 100% is assumed as a worst case default value due to lack of reliable data.Thus, twice as high absorption is assumed compared to oral absorption (Guidance on Information Requirements and Chemical Safety Assessment, R8).
Extrapolation oral to inhalation: AF 2
DERIVATION OF DNELs
DNELs derived from subchronic repeated dose toxicity NOAEL (OECD guideline 408)
General population-DNEL long-term for inhalation route (systemic): 12.2 mg/m³
Start value: 1650 mg/kg bw/d
Route of original study: oral
Dose descriptor starting point after route-to-route extrapolation: 611.11 mg/m³
For general population the corrected inhalation NOEC is calculated according to the following equation:
corrected inhalation NOAEC = oral NOAEL x 1/sRVrat x ABSoral-rat/ ABSinh-human
= 1650 x 1/1.152 x 50/100
In order to implement human body weight scaling as recommended by ECHA Guidance R.8 (version 2.1, November 2012), the respiratory volume was corrected for 60 kg body weight:
sRV (human, 8h) = 6.7 m³/kg bw/60 kg = 0.1117 m³/kg bw/8h
plus the allometric scaling from rat:
sRV(rat, 8h) = sRV (human, 8h) x allometric scaling factor = 0.1117 x 4 = 0.45 m³/kg bw/8h
and for the exposure time of 24h:
sRV(rat, 24h) = sRV(rat, 8h) x 24/8 =1.35m³/kg bw/24h.
Under consideration of body weight scaling the corrected NOEC was calculated as follows:
= 1650 x 1/1.35 x 50/100
The corrected inhalation NOAECgeneral population (24 h) is therefore:
= 611.11 mg/m³ (24 h)
Overall AF: 1*2*1*2.5*10*1 = 50
This DNEL does not address the potential for local irritation. The risk characterisation will consider whether specific risk management measures are necessary to protect against local effects.
general population-DNEL long-term for dermal route (systemic): 8.25 mg/kg bw/d
Start value: 1650 mg/kg bw/d
Route of original study: oral
Dose descriptor starting point after route-to-route extrapolation: 1650 mg/kg bw/d
Overall AF: 1*2*4*2.5*10*1 = 200
general population-DNEL long-term for oral route (systemic): 8.25 mg/kg bw/d
Start value: 1650 mg/kg bw/d
Route of original study: oral
Overall AF: 1*2*4*2.5*10*1 = 200
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.