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EC number: 221-975-0 | CAS number: 3302-10-1
- 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

Bioaccumulation: aquatic / sediment
Administrative data
Link to relevant study record(s)
- Endpoint:
- bioaccumulation in aquatic species: fish
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1999-04-19 to 1999-07-15
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- , but performed to an older version of the guideline.
- Qualifier:
- according to guideline
- Guideline:
- other: "Bioaccumulation test of chemical substance in fish and shellfish" in Prescribing the Items of the Test Relating to the New Chemical Substance (1974, Order of the Prime Minister of Health and Welfare, MITI No.1). This guideline corresponds to OECD 305 C.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)
- Version / remarks:
- adopted 12 May 1981
- Deviations:
- yes
- Remarks:
- a lower number of fish was used per exposure group. However, the number of fish analysed per time point was according to OECD 305.
- GLP compliance:
- yes
- Radiolabelling:
- no
- Details on sampling:
- - Sampling intervals/frequency for test organisms: after two, three, four and six weeks (n = 2 per exposure concentration)
- Sampling intervals/frequency for test medium samples: 2x/week (n = 1)
- The controls were analysed before initiation and termination of exposure (n = 2). - Vehicle:
- yes
- Remarks:
- HCO-40; - 1 mg/L nominal concentration: 10 mg/L HCO-40; - 0.1 mg/L nominal concentration: 1 mg/L HCO-40;
- Test organisms (species):
- Cyprinus carpio
- Details on test organisms:
- TEST ORGANISM
- Common name: carp
- Source: Sugishima fish farm (Japan)
- Length at study initiation (mean): 10.3 cm
- Weight at study initiation (mean): 26.1 g
- Health status: fish showing visible abnormal signs were removed before and during acclimation
- Description of housing/holding area: flow-through system
- Feeding during test
- Food type: pelleted feed for carp
- Amount: ca. 2 % of body weight
- Frequency: 2x/day
ACCLIMATION
- Acclimation period: 28 d
- Acclimation conditions (same as test or not): yes
- Type and amount of food: pelleted feed for carp, ca. 2 % of body weight
- Feeding frequency: 2x/day - Route of exposure:
- aqueous
- Justification for method:
- aqueous exposure method used for following reason: According to ECHA guidance document R.7c (2017) preferred route of exposure for substaces with acceptable water solubility (>0.1 mg/L - test item: 0.7 g/L) and moderate log Kow (below 6 - test item: 3.2)
- Test type:
- flow-through
- Water / sediment media type:
- natural water: freshwater
- Total exposure / uptake duration:
- 6 wk
- Test temperature:
- 25 +/- 2 °C
- pH:
- 7 +/- 1
- Dissolved oxygen:
- 7.4-8.1 mg/L
- Details on test conditions:
- TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100-L glass tank
- Renewal rate of test solution (frequency/flow rate): 800 mL/min
- exposure groups (nominal): 1 mg/L; 0.1 mg/L; control group;
- No. of organisms per vessel: 11 fish/concentration; 5 control fish
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1 (blank without test substance), 1 (recovery test)
TEST MEDIUM / WATER PARAMETERS
- Intervals of water quality measurement: 2x/week
RANGE-FINDING / PRELIMINARY STUDY
- Results used to determine the conditions for the definitive study: 48-h LC50 (Oryzias latipes): 160 mg/L - Nominal and measured concentrations:
- nominal: 0.1 and 1.0 mg/L
- Reference substance (positive control):
- not specified
- Details on estimation of bioconcentration:
- - observations/measurements: weight, length, lipid content (at test start);
- test item analyses:
test water (2x/week), test fish (after 2, 3, 4, and 6 weeks; 2 fish per concentration level), control fish before initiation and termination of exposure (2 fish, each).
- BCF = concentration of test substance in fish (based on whole fish wet weight)/concentration of test substance in water - Lipid content:
- 3.5 %
- Time point:
- start of exposure
- Conc. / dose:
- >= 0.932 - <= 0.936 mg/L
- Temp.:
- 25 °C
- pH:
- 7
- Type:
- BCF
- Value:
- >= 0.5 - <= 1.7 L/kg
- Basis:
- whole body w.w.
- Remarks:
- based on individual concentration results for fish (n= 2 at each time point)
- Time of plateau:
- 2 wk
- Calculation basis:
- steady state
- Remarks on result:
- other: based on arithmetic mean values for each time point, steady state was reached between 2 and 3 weeks.
- Remarks:
- Nominal exposure concentration: 1 mg/L
- Key result
- Conc. / dose:
- >= 0.092 - <= 0.094 mg/L
- Temp.:
- 25 °C
- pH:
- 7
- Type:
- BCF
- Value:
- >= 4.1 - <= 7 L/kg
- Basis:
- whole body w.w.
- Remarks:
- based on individual concentration results for fish (n= 2 at each time point)
- Time of plateau:
- 4 wk
- Calculation basis:
- steady state
- Remarks on result:
- other: based on arithmetic mean values for each time point, steady state was reached between 3 and 4 weeks.
- Remarks:
- Nominal exposure concentration: 0.1 mg/L
- Details on kinetic parameters:
- No kinetic parameters determined.
- Metabolites:
- No metablites detected.
- Results with reference substance (positive control):
- No positive control
- Details on results:
- Test fish did not show any abnormal appearance at both test item concentrations applied.
- Validity criteria fulfilled:
- yes
- Conclusions:
- No significant bioaccumulation potential is to be expected for 3,5,5-trimethylhexanoic acid based on the measured BCF of <= 7.0 (steady state) determined according to the MITI protocol, which corresponds to OECD 305 C.
- Executive summary:
To determine any potential for aquatic bioaccumulation of the submission substance, the bioconcentration factor for fresh water fish was determined using carp (Cyprinus carpio). The valid test was performed compliant with GLP according to OECD 305C (1981), following the steady state method. Based on preliminary acute toxicity testing (LC50 (Oryzias latipes; 48 h) = 160 mg/L), two exposure concentrations of 1.0 and 0.10 mg/L had been applied in a flow through system using glass aquaria (25 °C).
Aquatic test item concentrations were determined 2 times a week, and concentrations in fish were determined after two, three, four and six weeks. At each time point 2 fish per concentration level were used and extracted separately after weighing (wet weight). A mean lipid content of 3.5% had been determined at the start of exposure for the fish used.
Steady state (plateau) was reached between 2 and 3 weeks for 1 mg/L nominal concentration (>= 0.932 mg/L <= 0.936 mg/L measured) and between 3 and 4 weeks for 0.1 mg/L nominal concentration (>= 0.0925 mg/L <= 0.0943 mg/L measured). The highest BCF determined based on individual concentration results for fish (n= 2 at each time point) was 7.0 L/kg (whole body wet weight).
Concluding, these valid results convincingly demonstrate that there is no relevant aquatic bioaccumulation potential for 3,5,5-trimethylhexanoic acid (NITE, 2000).
Reference
Details on results:
Weeks | 2 | 3 | 4 | 6 | |
1st Concentration (1 mg/L nominal) |
Test substance concentration (mg/L) | 0.935 | 0.935 | 0.932 | 0.936 |
Bioconcentration factor (L/kg) | 1.6 | 0.6 | 1.7 | 0.6 | |
1.7 | 1.3 | 1.4 | 0.5 | ||
2nd Concentration (0.1 mg/L nominal) |
Test substance concentration (mg/L) | 0.0932 | 0.0925 | 0.0930 | 0.0943 |
Bioconcentration factor (L/kg) | < 3.1 | 7.0 | 5.7 | 4.8 | |
< 3.1 | < 3.1 | 4.1 | 4.9 |
Description of key information
No significant bioaccumulation potential is expected for 3,5,5-trimethylhexanoic acid based on a measured BCF according to the MITI protocol, which corresponds to OECD 305 C (NITE, 2008). The BCF at the lower test concentration (0.1 mg/L) was < 3.1-7.0, while the BCF at the higher test concentration (1 mg/L) was lower (0.5-1.7).
Key value for chemical safety assessment
- BCF (aquatic species):
- 7 L/kg ww
Additional information
To determine any potential for aquatic bioaccumulation of the submission substance, the bioconcentration factor for fresh water fish was determined using carp (Cyprinus carpio). The valid test was performed compliant with GLP according to OECD 305C (1981), following the steady state method. Based on preliminary acute toxicity testing (LC50 (Oryzias latipes; 48 h) = 160 mg/L), two exposure concentrations of 1.0 and 0.10 mg/L had been applied in a flow through system using glass aquaria (25 °C).
Aquatic test item concentrations were determined 2 times a week, and concentrations in fish were determined after two, three, four and six weeks. At each time point 2 fish per concentration level were used and extracted separately after weighing (wet weight). A mean lipid content of 3.5% had been determined at the start of exposure for the fish used.
Steady state (plateau) was reached between 2 and 3 weeks for 1 mg/L nominal concentration (>= 0.932 mg/L <= 0.936 mg/L measured) and between 3 and 4 weeks for 0.1 mg/L nominal concentration (>= 0.0925 mg/L <= 0.0943 mg/L measured). The highest BCF determined based on individual concentration results for fish (n= 2 at each time point) was 7.0 L/kg (whole body wet weight).
Concluding, these valid results convincingly demonstrate that there is no relevant aquatic bioaccumulation potential for 3,5,5-trimethylhexanoic acid (NITE, 2000).
A supporting QSAR study is available (ECT, 2008). The log BCF of 3,5,5-trimethylhexanoic acid was estimated to be 0.5 (BCF 3.2 L/kg ww) by using the BCFWIN program (v2.17) as part of US EPA EPI Suite(TM). This fits very well to the experimentally determined data and further corroborates that the submission substance will not bioaccumulate.
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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