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Diss Factsheets
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EC number: 202-696-3 | CAS number: 98-73-7
- 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
Genetic toxicity in vitro
Description of key information
Link to relevant study records
- Endpoint:
- in vitro cytogenicity / micronucleus study
- Remarks:
- Type of genotoxicity: chromosome aberration
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Study performed according to OECD guideline, detailed study report, GLP conformity. The study was also referred to in the EU risk assessment report of the substance (2009).
- Qualifier:
- according to guideline
- Guideline:
- other: OECD GUIDELINE FOR THE TESTING OF CHEMICALS DRAFT PROPOSAL FOR A NEW GUIDELINE 487: In Vitro Mammalian Cell Micronucleus Test (MNvit), 2nd Version
- GLP compliance:
- yes (incl. QA statement)
- Type of assay:
- in vitro mammalian cell micronucleus test
- Species / strain / cell type:
- Chinese hamster lung fibroblasts (V79)
- Details on mammalian cell type (if applicable):
- V79 cell line: obtained from LMP, Technical University of Darmstadt, Germany; stored under liquid nitrogen in the cell bank of RCC Cytotest Cell Research GmbH; before freezing each batch is screened for mycoplasm contamination and checked for karyotype stability - for the reason of quality assurance.
Cell cultures of V79:
Thawed stock cultures are propagated at 37 °C in 80 square centimetre plastic flasks. About 5*10^5 cells per flask are seeded in 15 ml of MEM (minimal essential medium from Seromed, 12247 Berlin, Germany) supplemented with 10 % fetal calf serum (from PAA Laboratories GmbH, 35091 Cölbe, Germany). The cells are subcultured twice weekly. The cell cultures are incubated at 37 °C in a humidified atmosphere with 1.5 % carbon dioxide (98.5 % air). - Metabolic activation:
- with and without
- Metabolic activation system:
- S9 mix: Phenobarbital/ß-naphtoflavone induced rat liver S-9, homogenised and diluted with a KCl solution (1:3), then centrifugation at 9000 g, then aliquots stored deep frozen until S-9 mix prepared according to Ames et al. (1975)
- Test concentrations with justification for top dose:
- 2.9, 5.9, 11.7, 23.4, 46.9, 93.8, 187.5, 375.0, 750.0 and 1500.0 microgram/ml; precipitation occurred at the highest concentration with the S-9 mix.
- Vehicle / solvent:
- - Vehicle(s)/solvent(s) used: DMSO
On the day of the experiment immediately before treatment, the test item was dissolved in DMSO (purity 99.5 %). Final concentration of DMSO in the culture medium was 0.5 % (v/v). The solvent was chosen to its solubility properties and its relative non-toxicity in the cell cultures. - Untreated negative controls:
- yes
- Remarks:
- Minimal essential medium with Hanks salts
- Negative solvent / vehicle controls:
- yes
- Remarks:
- culture medium with 0.5 % (v/v) DMSO
- Positive controls:
- yes
- Positive control substance:
- other: without metabolic activation: Colcemid, MMC (Mitomycin C); with metabolic activation: CPA (cyclophosphamide)
- Details on test system and experimental conditions:
- exposure period: 4 h
recovery: 20 h
preparation interval: 24 h - Statistics:
- Statistical significance of the results was confirmed by means of the Chi square test.
- Conclusions:
- Interpretation of results (migrated information):
ambiguous
The result from the in vitro micronucleus test is ambiguous since treatment with S9 mix induced weak increases in micronucleus (positive result) and without S9 mix was negative.
Reference
In the absence and presence of S-9 mix, no clear cytotoxicity was observed up to the highest applied concentration.
In the absence of metabolic activation, a statistically significant increase in the percentage of micronucleated cells was observed after 4 h treatment with 375 microgram/ml. Although the increase of 2.15 % was statistically significantly higher than the corresponding control (0.80 % micronucleated cells), the value did not exceed the laboratory's historical control range (0.0 -2.2 % micronucleated cells) and no dose-dependency was observed. Therefore, this observation was regarded as biologically irrelevant.
In contrast, in the presence of S-9 mix, the test item induced an increase in the percentage of micronucleated cells in a dose-related manner. At the two highest scored concentrations (750 and 1500 microgram/ml), the values of 3.2 % and 4.95 %, respectively, were statistically significantly higher than the corresponding control (1.60 % micronucleated cells) and exceeded the laboratory's historical control range (0.0 - 2.5 % micronucleated cells). The observation was therefore regarded as biologically relevant.
Either colcemid (7.5 or 10 microgram/ml), Mitomycin C (0.03 or 0.1 microgram/ml), or CPA (10 or 25 microgram/ml) were scored as positive controls and showed a distinct increase in the percentage of micronucleated cells.
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed (positive)
Additional information
In respect of mutagenicity of 4-TERT-BUTYLBENZOIC ACID the EU risk assessment report (2009) states (p. 67 and p. VII) that due to the positive in vitro micronucleus test and the fact that clastogenicity and aneugenicity were not distinguished in this test there would be concern for local clastogenic effects and aneugenic effects could not be excluded. Therefore further testing for clarification was recommended, preferably a combination of an in vivo COMET assay (directly exposed tissue and liver) and a bone marrow micronucleus test.
The EU risk assessment also laid out: An in vivo test on chromosomal aberrations in rats is negative for doses which correspond to the MTD. Oral bioavailability can be assumed from the physico-chemical data. This is in line with the fact that toxic effects were observed after acute and subacute oral application of low doses of the substance as well as the weak local effects (reduction of mitotic indices) in the in vivo chromosomal aberration test. There is sufficient evidence to conclude, that a clastogenic potential of ptBBA observed in vitro is unlikely to be expressed in germ cells in vivo.
The presented data in this dossier falls short of the recommendation in the EU risk assessment to generate more in vivo data. However, two out of three studies gave negative results and the prevention of animal testing is also a target of REACH wherever possible. The registrants will therefore await and abide the decision of the ECHA if the recommended studies have to be conducted.
Justification for selection of genetic toxicity endpoint
Treatment with S9 mix induced weak increases in micronucleus.
Justification for classification or non-classification
Regarding all given results there is not enough evidence for a classification as mutagenic at present. However, the substance was found to be genotoxic in one study. Therefore the substance is flagged as "positive" in respect of genetic toxicity in this preliminary evaluation.
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.
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