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EC number: 202-485-6 | CAS number: 96-17-3
- 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
Endpoint summary
Administrative data
Key value for chemical safety assessment
Additional information
Mutagenicity in bacterial cells
No valid study on the genetic toxicity properties of 2-methylbutanal was located. Negative results in the Ames test with and without metabolic activation were reported in two independent publications, but the number of test strains used was low, and the documentation was poor. The reliability of these studies is therefore low (RL4) though the results may be used to demonstrate a lack of genotoxic potential in a weight of evidence approach.
It is known that linear and branched alkyl aldehydes of a comparable chain length were negative in the Ames test, with and without metabolic activation. This was confirmed by the results of a structure-activity analysis using the OECD Toolbox v. 1.1. Starting with data from 1524 aldehydes, refinement ( i.e. elimination of alkenes, arenes, carboxylic acids, alpha-beta unsaturated aldehydes, etc.) resulted in a set of branched and linear monofunctional aldehydes with a carbon chain length of C2 to C9 which were all negative in the Ames test (i.e. -1.00 in the attached plot). A further selection of the five nearest neighbours (C3-C7; brownish dots) to 2-methylbutanal (red dot) were all negative. It is therefore assumed that 2-methylbutanal is not genotoxic in bacteria in vitro.
Read across: aldehyde mutagenicity and carcinogenicity data
The table below summarises available data on two closely related aldehydes, valeraldehyde, isovaleraldehyde, and isobutyraldehyde which can be used for read across. Structure, chain length, reactivity, physico-chemical properties, and metabolism of these aliphatic aldehydes are very similar, thus justifying cross reading of results from these substances to 2-methylbutyraldehyde.
It may be observed that the aldehydes give mostly negative results in the Ames test (bacterial cells), but positive results with mammalian cells in vitro, which is in sharp contrast to the negative results obtained in-vivo using the Mouse Micronucleus Test, or in carcinogenicity assays.
Study |
Substance |
Reliability |
GLP |
Test type/ |
Guideline |
Results |
Remarks |
In vitro tests; |
|||||||
NTP |
Valeraldehyde |
2 |
no data |
Ames |
similar |
negative |
tested up to 2000 µg/plate with and without metab. activ. |
In vitro tests, |
|||||||
Brambilla |
Valeraldehyde |
2 |
no |
HPRT |
similar |
positive |
V79 cells; |
Martelli 1994 |
Valeraldehyde |
2 |
no |
Gen. Tox. |
similar |
positive |
primary hepatocytes; |
Marinari |
Valeraldehyde |
2 |
no |
DNA damage |
no TG |
positive |
single strand breaks, |
BASF SE |
Read across; |
1 |
yes |
HPRT |
according |
negative |
CHO cells; |
In vivo tests; |
|||||||
BASF AG |
Read across; |
1 |
yes |
MNT |
Similar to |
negative |
Read across; 3 concentrations up to |
NTP |
Read across; |
2 |
no data |
MNT |
Similar to |
negative |
3 repeat single ip injections; |
NTP |
Read across; |
2 |
no data |
Mammalian bone marrow |
Similar to |
positive |
Read across; 5 concentrations up to |
NTP |
Read across |
2 |
no data |
Chronic cancer study |
OECD 451 |
negative |
mouse |
NTP |
Read across |
2 |
no data |
Chronic cancer study |
OECD 451 |
negative |
rat |
The Ames test is negative for several other related aldehydes (e.g. isovaleraldehyde, butyraldehyde, isobutyraldehyde, propionaldehyde).
Results of in vitro tests with mammalian cell systems are predominantly positive e.g Brambilla (1989). In contrast, the HPRT test for isobutyraldehyde (BASF AG, 1999) was negative.
Regarding in vivo genotoxicity, Isovaleraldehyde was tested by BASF in an in vivo mammalian erythrocyte micronucleus test. The result was negative (no increase in polychromatic erythrocytes containing neither small nor large micronuclei). The study satisfies the requirements of OECD TG 474.
Further, isobutyraldehyde was thoroughly tested by NTP. A mouse bone marrow micronucleus test was negative, i.e. in two independent tests, there was no significant increase compared to controls of micronucleated polychromatic erythrocytes from animals treated with three repeat doses (24 h interval) of isobutyraldehyde up to the maximum (single) dose of 1250 mg/kg bw. In contrast, in two tests for induction of chromosomal aberrations in mouse bone marrow, results were clearly positive. After intraperitoneal injection of increasing isobutyraldehyde single doses up to a maximum of 1750 mg/kg bw, increasing frequencies of aberrant cells were observed. Significant increases in aberrant cells compared to controls was only seen at doses which caused notable toxicity (1500 and 1750 mg/kg bw). These doses were higher than the maximum single dose administered in the micronucleus test at a single day.
Given these conflicting results, NTP decided to perform long-term inhalation cancer studies in rats and mice similar to the OECD test guideline 451 (isobutyraldehyde concentrations 0, 1500, 3000, and 6000 mg/m³). There was no evidence of carcinogenic potential in males or females of either species.
Based on the above Read Across, it is concluded that 2-methylbutyraldehyde is not genotoxic.
Short description of key information:
2-methylbutyraldehyde is considered to be not genotoxic, based on the results of closely related short chained (C3 - C9) linear and branched alkyl aldehydes that were evaluated using the OECD Toolbox v. 1.1, and a read across approach which included also other endpoints and in-vivo data. Valid data related to the genetic toxicity of 2-methylbutyraldehyde could not be located, but two Ames studies of low reliability (RL4) are in line with the overall result.
Endpoint Conclusion: No adverse effect observed (negative)
Justification for classification or non-classification
No classification required. Classification criteria are not met.
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