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EC number: 201-195-7 | CAS number: 79-31-2
- 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:
- 184 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 25
- Modified dose descriptor starting point:
- NOAEC
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
- Explanation for the modification of the dose descriptor starting point:
Substance is not classified for actute inhalative hazard thus no hazard conclusion needs to be drawn.
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:
- high hazard (no threshold derived)
- Most sensitive endpoint:
- skin irritation/corrosion
DNEL related information
Workers - Hazard via dermal route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 3.75 mg/kg bw/day
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 100
- Modified dose descriptor starting point:
- NOAEL
Acute/short term exposure
- Hazard assessment conclusion:
- hazard unknown but no further hazard information necessary as no exposure expected
DNEL related information
- Explanation for the modification of the dose descriptor starting point:
According to ECHA guideline R8 an acute dermal hazard conclusion has to drawn in case an acute toxicity hazard leading to C&L has been identified AND peak exposure is be expected. As no peak exposure up to our knowledge and we have not been informed by our customers about such peak exposure no acute, dermal hazard conclusion is identified.
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:
- high hazard (no threshold derived)
Workers - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- high hazard (no threshold derived)
Additional information - workers
Acute / short-term exposure - systemic effects
In acute toxicity studies, isobutyric acid has been shown to be of low systemic toxicity except for dermal toxicity.
LD50 oral: 2230 mg/kg bw
LC0 inhalation, 8-h exposure: 9590 mg/m³
LD50 dermal: 474 mg/kg bw
From present studies, reliable short-term dose response relations cannot be deduced. Available data do not provide sufficient information on sublethal toxic effects to gather NOAELs as starting points. DNELs cannot be derived.
Acute /short-term exposure - local effects
Isobutyric acid is corrosive to skin and to the eye. Corrosive effects are observed after topical application of as little as 10 µL test substance (Smyth 1962). Weaker effects have not been examined. Dose descriptors for the deduction of a DNEL for acute local effects are not available.
Unlike these findings, inhalational exposure to saturated vapor concentrations was possible for 8 hours without mortality. But severe mucosal irritation is reported during exposure. On day 1, dyspnea was still observed in 1 of 12 test animals. For inhalation exposure, severe effects are reported as for dermal application, but this information is not suited as dose descriptors for the deduction of a DNEL.
Long term exposure systemic effects
Data for isobutyric acid on long term exposure could not be identified. To assess the risk of long-term exposure - systemic effects for isobutyric acid, data for isobutanol as supporting substance will be used as substitute on the following reasons.
After administration, isobutanol will rapidly be metabolized in vivo to isobutyraldehyde by alcohol dehydrogenases and subsequently to isobutyric acid by aldehyde dehydrogenases. In the course of metabolic transformation of isobutanol, isobutyric acid is generated rapidly and predominantly as intermediary metabolite. Thus, it is justified to use isobutanol as supporting substance in the evaluation of the systemic effects of isobutyric acid.
Supporting substance: isobutanol - Derivation of DNELs for isobutyric acid
There are several repeated dose toxicity studies available with isobutanol. As conservative approach, the study with the lowest NOAEL will be used in the deduction of DNELs.
Dermal systemic DNEL
The dermal DNEL will be obtained based on an oral NOAEL for isobutanol of 316 mg/kg bw/day (EPA/Res. Triangle Inst. 1987; Repeated dose toxicity, Sect. 7.5.1). Using the respective molecular weights (isobutyric acid 88.11, isobutanol 74.12), the NOAEL for isobutanol is converted to a NOAEL for isobutyric acid.
Oral systemic NOAEL for isobutyric acid: 375 mg/kg bw
For the oral-to-dermal extrapolation, a default factor of 1 is used. With an overall assessment factor of 100 (allometric scaling factor 4, factor for remaining interspecies differences 2.5, intraspecies factor 5 (worker), sub-chronic to chronic exposure factor 2 ), a DNEL of 3.75 mg/kg bw/day for isobutyric acid is derived.
Dermal systemic DNEL isobutyric acid: 3.75 mg/kg bw/day
Inhalation DNEL
Long term inhalation exposure data on systemic effects are available from a 90 day combined neurotoxicity/repeated dose toxicity study (Li/Monsanto 1999; Repeated dose toxicity, Sect. 7.5.3) and from a two generation reproduction study of isobutanol (OPP/AAC 2003; Toxicity to reproduction , Sect. 7.8.1). For both studies, a NOAEC (isobutanol) of 2500 ppm (7700 mg/m³, highest dose applied) has been determined. Using the respective molecular weight and the standard molar volume (24.06 L/mol at 20 °C), the NOAEC isobutanol can be converted to the NOAEC isobutyric acid.
Inhalation systemic NOAEC for isobutyric acid: 2500 ppm (9150 mg/m³).
Exposure was 6 h per day. This NOAEC has to be modified with respect to exposure conditions of workers (exposure time 8 h/d, increased respiratory rate = wRV of 10 m³/8h) resulting in a corrected starting point NOAEL of 4600 mg/m³. The overall assessment factor (25) consists of a factor for remaining interspecies differences of 2.5, an intraspecies factor of 5 (worker) and a sub-chronic-to-chronic exposure factor of 2. The allometric scaling factor is already accounted for in the derivation of the corrected starting point NOAEC. With this overall assessment factor, a DNEL of 184 mg/m³ for isobutyric acid is calculated.
Inhalation systemic DNEL isobutyric acid: 184 mg/m³.
Long-term exposure - local effects
For isobutyric acid, no data on local effects of long-term exposure are available. Long term exposure studies with isobutyric aid have not been conducted. Due to the severe corrosive reaction of isobutyric acid, effects similar to acute toxicity tests will occur. Dose descriptors for the derivation of DNELs are not available.
General Population - Hazard via inhalation route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 92 mg/m³
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 50
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:
- high hazard (no threshold derived)
DNEL related information
General Population - Hazard via dermal route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 1.88 mg/kg bw/day
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 200
- Modified dose descriptor starting point:
- NOAEL
Acute/short term exposure
- Hazard assessment conclusion:
- hazard unknown but no further hazard information necessary as no exposure expected
DNEL related information
- Explanation for the modification of the dose descriptor starting point:
According to ECHA guideline R8 an acute dermal hazard conclusion has to drawn in case an acute toxicity hazard leading to C&L has been identified AND peak exposure is be expected. As no peak exposure up to our knowledge and we have not been informed by our customers about such peak exposure no acute, dermal hazard conclusion is identified.
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:
- high hazard (no threshold derived)
General Population - Hazard via oral route
Systemic effects
Long term exposure
- Hazard assessment conclusion:
- DNEL (Derived No Effect Level)
- Value:
- 1.88 mg/kg bw/day
- Most sensitive endpoint:
- repeated dose toxicity
DNEL related information
- Overall assessment factor (AF):
- 200
- Modified dose descriptor starting point:
- NOAEL
Acute/short term exposure
- Hazard assessment conclusion:
- no hazard identified
DNEL related information
General Population - Hazard for the eyes
Local effects
- Hazard assessment conclusion:
- high hazard (no threshold derived)
Additional information - General Population
Acute / short-term exposure - systemic effects
In acute toxicity studies, isobutyric acid has been shown to be of low systemic toxicity except for dermal toxicity.
LD50 oral: 2230 mg/kg bw
LC0 inhalation, 8-h exposure: 9590 mg/m³
LD50 dermal: 474 mg/kg bw
From present studies, reliable short-term dose response relations cannot be deduced. Available data do not provide sufficient information on sublethal toxic effects to gather NOAELs as starting points. DNELs cannot be derived.
Acute /short-term exposure - local effects
Isobutyric acid is corrosive to skin and to the eye. Corrosive effects are observed after topical application of as little as 10 µL test substance (Smyth 1962). Reduced effects have not been examined. Dose descriptors for the deduction of a DNEL for acute local effects are not available.
Unlike these findings, inhalational exposure to saturated vapor concentrations was possible for 8 hours without mortality. But severe mucosal irritation is reported during exposure. On day 1, dyspnea was still observed in 1 of 12 test animals. For inhalation exposure, severe effects are reported as for dermal application, but this information is not suited as dose descriptors for the deduction of a DNEL.
Long term exposure systemic effects
Data for isobutyric acid on long term exposure could not be identified. To assess the risk of long-term exposure - systemic effects for isobutyric acid, data for isobutanol as supporting substance will be used as substitute on the following reasons.
After administration, isobutanol will rapidly be metabolized in vivo to isobutyraldehyde by alcohol dehydrogenases and subsequently to isobutyric acid by aldehyde dehydrogenases. In the course of metabolic transformation of isobutanol, isobutyric acid is generated rapidly and predominantly as intermediary metabolite. Thus, it is justified to use isobutanol as supporting substance in the evaluation of the systemic effects of isobutyric acid.
Supporting substance: isobutanol - Derivation of DNELs for isobutanol
There are several repeated dose toxicity studies available with isobutanol. As conservative approach, the study with the lowest NOAEL will be used in the deduction of DNELs.
Dermal DNEL
The dermal DNEL will be obtained based on an oral NOAEL for isobutanol of 316 mg/kg bw/day (EPA/Res. Triangle Inst. 1987; Repeated dose toxicity, Sect. 7.5.1). Using the respective molecular weights (isobutyric acid 88.11, isobutanol 74.12), the NOAEL for isobutanol is converted to a NOAEL for isobutyric acid.
Oral systemic NOAEL for isobutyric acid: 375 mg/kg bw
For the oral-to-dermal extrapolation, a default factor of 1 is used. With an overall assessment factor of 200 (allometric scaling factor 4, factor for remaining interspecies differences 2.5, intraspecies factor 10 (general population), sub-chronic to chronic exposure factor 2 ), a DNEL of 1.88 mg/kg bw/day for isobutyric acid is derived.
Dermal systemic DNEL isobutyric acid: 1.88 mg/kg bw/day
Inhalation DNEL
Long term inhalation exposure data on systemic effects are available from a 90 day combined neurotoxicity/repeated dose toxicity study (Li/Monsanto 1999; Repeated dose toxicity, Sect. 7.5.3) and from a two generation reproduction study of isobutanol (OPP/AAC 2003; Toxicity to reproduction , Sect. 7.8.1). For both studies, a NOAEC (isobutanol) of 2500 ppm (7700 mg/m³, highest dose applied) has been determined. Using the respective molecular weight and the standard molar volume (24.06 L/mol at 20 °C), the NOAEC isobutanol can be converted to the NOAEC isobutyric acid.
Inhalation systemic NOAEC for isobutyric acid: 2500 ppm (9150 mg/m³).
Exposure was 6 h per day. This NOAEC has to be modified with respect to exposure conditions of workers (exposure time 8 h/d, increased respiratory rate = wRV of 10 m³/8h) resulting in a corrected starting point NOAEL of 4600 mg/m³. The overall assessment factor (50) consists of a factor for remaining interspecies differences of 2.5, an intraspecies factor of 10 (general population) and a sub-chronic-to-chronic exposure factor of 2. The allometric scaling factor is already accounted for in the derivation of the corrected starting point NOAEC. With this overall assessment factor, a DNEL of 92 mg/m³ for isobutyric acid is calculated.
Inhalation systemic DNEL isobutyric acid: 92 mg/m³.
Oral DNEL
The oral DNEL will be obtained based on an oral NOAEL for isobutanol of 316 mg/kg bw/day (EPA/Res. Triangle Inst. 1987; Repeated dose toxicity, Sect. 7.5.1). Using the respective molecular weights (isobutyric acid 88.11, isobutanol 74.12), the NOAEL for isobutanol is converted to a NOAEL for isobutyric acid.
Oral systemic NOAEL for isobutyric acid: 375 mg/kg bw
This NOAEL is used uncorrected as starting point. With an overall assessment factor of 200 (allometric scaling factor 4, factor for remaining interspecies differences 2.5, intraspecies factor 10 (general population), sub-chronic to chronic exposure factor 2 ), a DNEL of 1.88 mg/kg bw/day for isobutyric acid is derived.
Oral systemic DNEL isobutyric acid: 1.88 mg/kg bw/day
Long-term exposure - local effects
For isobutyric acid, no data on local effects of long-term exposure are available. Long term exposure studies with isobutyric aid have not been conducted. Due to the severe corrosive reaction of isobutyric acid, effects similar to acute toxicity tests will occur. Dose descriptors for the derivation of DNELs are not available.
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