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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
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to microorganisms
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Acceptable, well documented publication which meets basic scientific principles
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- TETRATOX assay: Tetrahymena pyriformis population growth impairment test
- GLP compliance:
- no
- Analytical monitoring:
- no
- Vehicle:
- not specified
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- stock solutions were prepared by mixing test substance with sterile distilled water or with reagent-grade dimethyl sulfoxide (DMSO) just prior to use (within 1 hour). Concentration of DMSO in the test medium did not exceed 0.75% (max. 375 µL stock solution per 50 mL of medium). This concentration had no effect on the growth of the test organisms. - Test organisms (species):
- Tetrahymena pyriformis
- Details on inoculum:
- - Laboratory culture: yes
- Test organism: Tetrahymena pyriformis (strain GL-c) in log-growth-phase
- Initial biomass concentration: 2500 cells/mL (i.e. 0.20 mL of a 48-h culture) - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 40 h
- Remarks on exposure duration:
- test duration allowes for 8 to 9 cell cycles in controls.
- Test temperature:
- 27 ± 1°C
- Nominal and measured concentrations:
- nominal concentrations; at least five graduate concentration levels, individual concentrations not reported
- Details on test conditions:
- TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): Erlenmeyer flasks, foam-stoppered
- Material, size, headspace, fill volume: glas, 250 mL, 150 mL, 50 mL
- Aeration: no data
- No. of organisms per vessel: 1.25 E5 (2500 cell/mL) in log-growth phase
- No. of vessels per concentration (replicates): 2 + 1 blank
- No. of tests per substance: 3 replicate independent tests
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: sterile distilled water
- Culture medium different from test medium: no
- Test medium: Proteose peptone (5 g), D-glucose (5 g), Yeast extract (1 g,) Tris_HCl (1.2114 g) in 1000 mL distilled Water supplemented with 100 mL each of two salt solutions (Chlorides and Sulfates). Medium is sterilized.
OTHER TEST CONDITIONS
- Adjustment of pH: test solution not neutralized
EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Growth impairment: population density is measured spectrophotometrically (absorbance at 540 nm)
TEST CONCENTRATIONS
- Spacing factor for test concentrations: no data
- Range finding study: preliminary to the definite test (3 independent replicate assays) a range finding assay was performed (no further data reported)
STATISTICAL EVALUATION
- results are given as 50 % inhibitory growth concentration in mg/L (IGC50)
- IGC50 values and the 95% fiducial intervals are determined by Probit analysis using the percent control-normalized absorbance as the dependent variable and the toxicant concentration in mg/L as the independent variable - Reference substance (positive control):
- not specified
- Duration:
- 40 h
- Dose descriptor:
- IC50
- Effect conc.:
- 190 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth inhibition
- Remarks on result:
- other: reported value: Log (ICG50)E-1 = -0.3334
- Reported statistics and error estimates:
- no statistics reported
- Validity criteria fulfilled:
- not applicable
- Remarks:
- no guideline study
- Conclusions:
- The concentration of isobutyric acid to inhibit the growth of Tetrahymena pyriformis by 50 % (spectrophotometric measurement of cell density) was determined to be 2.15 mg/L.
- Executive summary:
In a valid 40 hour growth inhibition study, test cultures of the cilliate Tetrahymena pyriformis were exposed to isobutyric acid at five graduate concentrations under static conditions (individual concentrations not reported). The assay was performed in three independent replicate runs on the basis of a preceding range finding test. The IC50 value based on cell density was determined to be 2.15 mg/L indicating low to moderate toxicity of isobutyric acid to aqueous microorganisms (cilliates) (Schultz, 2006).
Reference
Description of key information
Isobutyric acid inhibited the cell growth of Tetrahyma pyriformis test cultures by 50 % at a concentration of 2.15 mg/mL.
Key value for chemical safety assessment
- EC50 for microorganisms:
- 2.15 mg/L
Additional information
From three tests identified, only one test is valid (Schulz, 1997). The documentation of the other two (BASF AG, 1989; Hoechst AG 1979) is insufficient for assessment.
Schulz 1997
In a valid 40 hour growth inhibition study, test cultures of the cilliate Tetrahymena pyriformis were exposed to isobutyric acid at five graduate concentrations under static conditions (individual concentrations not reported). The assay was performed in three independent replicate runs on the basis of a preceding range finding test.
The IC50 value based on cell density was determined to be 2.15 mg/L indicating low to moderate toxicity of isobutyric acid to aqueous microorganisms (cilliates) (Schultz, 2006).
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