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EC number: 201-944-8 | CAS number: 89-83-8
- 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:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- JAN 1986 - MAR 1986
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study with acceptable restrictions
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- GLP compliance:
- no
- Specific details on test material used for the study:
- - solid
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly industrial sewage
- Details on inoculum:
- - Source: OECD-facility
- Method: First, the sludge was settled and the supernatant was decanted. After centrifugation (20 min at 4000 rpm and 20°C) the supernatant was decanted. Approx. 1 g of the wet sludge was dried in order to calculate the amount of wet sludge to achieve a concentration of activated sludge of 6 g/L (dry weight) suspended solids. The calculated amount of sludge was first dissolved in synthetic medium and then filled up to a defined end volume with deionised water. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 3 h
- Remarks on exposure duration:
- with permanent aeration
- Test temperature:
- 22 °C
- pH:
- 7.3 - 7.4
- Nominal and measured concentrations:
- nominal concentrations: 1.6, 3.2, 6.3, 12.5, 25 and 50 mg/L
- Details on test conditions:
- Type: aquatic
- test concentration of activated sludge: 0.30 g/L (dry weight)
- test vessels: 300 mL glass Erlenmeyer flasks, filled volume 250 mL - Reference substance (positive control):
- yes
- Remarks:
- 3.5-dichlorphenol
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- 39.6 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Remarks on result:
- other: 31.8 - 55.1 mg/L
- Details on results:
- The concentrations of the test item and reference compound were not confirmed by analytical methods.
- Results with reference substance (positive control):
- EC50 of the reference compound 3.5-Dichlorophenol is in the range 5 - 30 mg/L.
- Validity criteria fulfilled:
- yes
- Remarks:
- The respiratory rates of the 2 controls differ less than 15 % and the EC50 of the reference compound 3.5-Dichlorophenol is in the range 5 - 30 mg/L.
- Conclusions:
- An 3h-EC50 of 39.6 mg/L was observed.
- Executive summary:
The toxicity of thymol to activated sludge was investigated according to OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test). An 3h-EC50 of 39.6 mg/L was determined.
- Endpoint:
- activated sludge respiration inhibition testing
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because the substance is found to be readily biodegradable and the applied test concentrations are in the range of concentrations that can be expected in the influent of a sewage treatment plant
Referenceopen allclose all
Substance |
Amount of test solution mL |
Concentration mg/L |
Amount nutrition medium mL |
Respiration rate mg/mL min O2 |
% Inhibition |
Thymol | 125 | 50 | 8 | 0.15 | 60.53 |
62.5 | 25 | 8 | 0.27 | 28 .95 | |
31.2 | 12.5 | 8 | 0.35 | 7.90 | |
15.6 | 6.3 | 8 | 0.35 | 7.90 | |
7.8 | 3.2 | 8 | 0.36 | 5.27 | |
3.9 | 1.6 | 8 | 0.41 | 0 | |
3.5 -Dichlophenol | 50 | 100 | 8 | 0 | 100 |
0.5 | 1 | 8 | 0.35 | 7.90 | |
1. Control | - | - | 8 | 0.37 | - |
2. Control | - | - | 8 | 0.4 | - |
Mean Control | - | - | - | 0.38 | - |
Endogen | - | - | - | 0 | - |
Description of key information
According to column 2 of REACH Annex VIII, an activated sludge respiration inhibition test does not need to be conducted as the substance is found to be readily biodegradable and the applied test concentrations are in the range of concentrations that can be expected in the influent of a sewage treatment plant. Nonetheless, the values derived from an OECD 209 guideline test have been used for risk assessment.
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test), 3h, activated sludge, result: 3h-EC50 of 39.6 mg/L was observed (Bayer AG, 1986), which was re-written at Currenta in 2009.
Key value for chemical safety assessment
- EC50 for microorganisms:
- 39.6 mg/L
Additional information
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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