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EC number: 941-453-2 | CAS number: -
Toxicological Summary
Administrative data
Workers - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 88 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):
- 20
- Modified dose descriptor starting point:
- NOAEC
- Value:
- 1 760 mg/m³
- Explanation for the modification of the dose descriptor starting point:
- default assessment factor for route-to-route extrapolation: 2
- AF for dose response relationship:
- 1
- Justification:
- default assessment factor
- AF for differences in duration of exposure:
- 2
- Justification:
- default assessment factor
- Justification:
- not considered, as an allometric scaling is not applied in the case of systemic effects after inhalation
- Justification:
- not considered, as an allometric scaling is not applied in the case of systemic effects after inhalation
- AF for intraspecies differences:
- 5
- Justification:
- default assessment factor
- AF for the quality of the whole database:
- 1
- Justification:
- default assessment factor
Acute/short term exposure
DNEL related information
Local effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Acute/short term exposure
DNEL related information
Workers - Hazard via dermal route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 100 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
- Modified dose descriptor starting point:
- NOAEL
- Value:
- 1 000 mg/kg bw/day
- Explanation for the modification of the dose descriptor starting point:
- Based on the physico-chemical properties of L-Threonine mother liquor (only partly soluble in water (396-490 g/L; calculated log P value below 0), a significant dermal uptake is not to be expected, i.e. the dermal absorption is assumed to be 10%. See also discussion below
- AF for dose response relationship:
- 1
- Justification:
- default assessment factor
- AF for differences in duration of exposure:
- 2
- Justification:
- default assessment factor
- AF for interspecies differences (allometric scaling):
- 4
- Justification:
- default assessment factor
- AF for other interspecies differences:
- 2.5
- Justification:
- default assessment factor
- AF for intraspecies differences:
- 5
- Justification:
- default assessment factor
- AF for the quality of the whole database:
- 1
- Justification:
- default assessment factor
Acute/short term exposure
DNEL related information
Local effects
Long term exposure
- Hazard assessment conclusion:
- no hazard identified
Workers - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- no hazard identified
Additional information - workers
DNELs for acute toxicity are not considered since long-term DNEL is sufficient to ensure that these effects do not occur.
Skin and eye irritation/corrosion: L-Threonine mother liquor was tested in GLP studies according to OECD guideline 404 and 405, which both gave no indications for skin and eye irritation.
Sensitization: For L-threonine mother liquor itself no studies are available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration. Biofert Plusz was not sensitizing in a valid study performed according to OECD Guideline 429.
Mutagenicity: For L-threonine mother liquor itself there are no studies available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration. Biofert Plusz was tested negative in different in vitro mutagenicity tests.
Reproductive toxicity: For L-threonine mother liquor itself there are no studies available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration. In rats no maternal and developmental toxicity was detected in a gavage study according to OECD Guideline 414 even at the high dose level of 1000 mg/kg bw/day.
DNEL Workers
DNEL Long-term - inhalation, systemic effects
For L-threonine mother liquor itself no studies with repeated dosing are available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration.
Relevant dose descriptor for the endpoint concerned: NOAEL of > 1000 mg/kg bw/day in rats in a 90-day oral toxicity study with GLP compliance according to OECD Guideline 408
Correction of starting point:
Differences in respiratory volumes: respiratory volume of the rat in 8 h corresponds to 0.38 m3/kg bw, additional correction for the higher standard respiratory volumes of workers compared to resting persons: correction factor = (1 ÷ 0.38) * (6.7 ÷ 10) = 1.76
Overall correction factor: 1.76
Corrected starting point: 1000 * 1.76 = 1760 mg/m3
Assessment factors relating to the extrapolation procedure:
Interspecies: not considered, as an allometric scaling is not applied in the case of systemic effects after inhalation
Intraspecies: 5 (default assessment factor)
Time extrapolation: 2 (default assessment factor)
Route to route extrapolation: 2 (default assessment factor)
Dose-response: 1 (default assessment factor [reliable NOAEL])
Quality of whole database: 1 (default assessment factor [completeness of available data])
Overall assessment factor: 5 * 2 * 2 * 1 * 1 = 20
DNEL Long-term - inhalation, systemic effects: 1760 mg/m3 ÷ 20 = 88 mg/m3
DNEL Long-term - dermal, systemic effects
For L-threonine mother liquor itself no studies with repeated dosing are available. Therefore, data for the read-across substance Biofert Plusz are taken into further consideration.
Relevant dose descriptor for the endpoint concerned: NOAEL of > 1000 mg/kg bw/day in rats in a 90-day oral toxicity study with GLP compliance according to OECD Guideline 408
Correction of starting point:
Differences in absorption: Oral absorption is assumed to be 100%, while dermal absorption is assumed to be 10% (based on the physico-chemical properties of L-Threonine mother liquor (only partly soluble in water (396-490 g/L; calculated log P value below 0), a significant dermal uptake is not to be expected)
Corrected starting point: 1000 * 100 / 10 = 10000 mg/kg bw/day
Assessment factors relating to the extrapolation procedure:
Interspecies: 4 * 2.5 (default assessment factor for allometric scaling)
Intraspecies: 5 (default assessment factor)
Time extrapolation: 2 (default assessment factor)
Route to route extrapolation: 1 (default assessment factor)
Dose-response: 1 (default assessment factor [reliable NOAEL])
Quality of whole database: 1 (default assessment factor [completeness of available data])
Overall assessment factor: 4 * 2.5 * 5 * 2 * 1 * 1 * 1 = 100
DNEL Long-term - dermal, systemic effects: 10000 mg/kg bw/day ÷ 100 = 100 mg/kg bw/day
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
Only workers in the chemical or the agriculture industry might be exposed to L-threonine mother liquor in accidental cases. As L-threonine mother liquor is not a consumer product, an exposure for the general population is not to be expected. Therefore, there is no necessity to derive DNELs for the general population.
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