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Diss Factsheets
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EC number: 202-409-1 | CAS number: 95-31-8
- 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
Long-term toxicity to fish
Administrative data
Link to relevant study record(s)
- Endpoint:
- fish early-life stage toxicity
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study with acceptable restrictions
- Justification for type of information:
- For hydrolysable substances used in aquatic ecotox tests, REACH Guidance Document R7b (2017), p. 86 states: :
“Where degradation is rapid (e.g. half-life < 1 hour), the available test data will frequently define the hazard of the degradation products since it will be these that have been tested. These data may be used to classify the parent substance in the normal way.
Where degradation is slower (e.g. half-life > 3 days), it may be possible to test the parent substance and thus generate hazard data in the normal manner using a suitable renewal regime. The subsequent degradation may then be considered in determining whether an acute or chronic hazard class should apply.
Where degradation rates fall between these two, testing of either parent and/or degradates should be considered on a case-by-case basis. “
TBBS hydrolyses with a DT50 of 1.8h (MITI 1996) or 9.53h (Monsanto 1984) thus falling in the category where either parent or degradation product could be tested. In the following considerations are discussed which kind of study is recommended:
1. In the case of the sulphenamide category, a study with the degradation product benzothiazole-2-thiol (MBT) is already available. This study (FELS test) has been performed in accordance similar to an accepted international guideline (OECD 210, FELS test) and has been evaluated as Klimisch 2.
2. There are acute and chronic ecotox studies with MBT and TBBS available. The results are presented in the table below (effect values are based on measured concentrations):
TBBS (mg/L) MBT (mg/L)
Daphnia 48h-EC 50 1.3 0.71
Daphnia 21d-NOEC >0.16 0.08
Fish 96h LC 50 1.38 0.73
Fish 89d NOEC use MBT data 0.048
Algae 72h-EC 50 0.071 0.5
72-hNOEC 0.023 0.066
Whereas for algae, TBBS appears to be more toxic, the effect values for TBBS and MBT in acute daphnia and fish exhibit comparable. This can also be seen in the chronic tests in daphnia. These results suggest that TBBS and its degradation product MBT have a similar toxicological profile and no relevant differences in a chronic fish test for TBBS would be expected.
As a conclusion the existing chronic fish test for MBT is sufficient to explain the toxicity of TBBS. - Principles of method if other than guideline:
- Method: Federal Register 50:TSCA Test Standard No. 797.1600. This test is comparable with the OECD-Guideline 210.
- GLP compliance:
- yes
- Specific details on test material used for the study:
- - Common name: 2-mercaptobenzothiazole
- Analytical monitoring:
- yes
- Vehicle:
- yes
- Test organisms (species):
- Oncorhynchus mykiss (previous name: Salmo gairdneri)
- Details on test organisms:
- Unfertilised rainbow trout eggs and sperm were individually packaged and shipped under refrigeration from Mount Lassen Farm, a certified disease-free trout hatchery located in Red Bluffs, California.
- Test type:
- flow-through
- Water media type:
- freshwater
- Total exposure duration:
- 89 d
- Hardness:
- 26 - 30 mg/L CaCO3 = 1.46 - 1.68 °dH
- Test temperature:
- 12 +/- 2°C
- pH:
- 6.9 - 7.4
- Dissolved oxygen:
- 7.1 - 11.2 mg/L
- Key result
- Duration:
- 89 d
- Dose descriptor:
- NOEC
- Effect conc.:
- 0.041 mg/L
- Nominal / measured:
- meas. (not specified)
- Conc. based on:
- test mat.
- Basis for effect:
- larval development
- Key result
- Duration:
- 89 d
- Dose descriptor:
- LOEC
- Effect conc.:
- 0.078 mg/L
- Nominal / measured:
- meas. (not specified)
- Conc. based on:
- test mat.
- Basis for effect:
- larval development
- Details on results:
- MATC = Maximum Acceptable Toxicant Concentration
geometric mean = 0.057 mg/l - Validity criteria fulfilled:
- not applicable
- Conclusions:
- For benzothiazole-2-thiol as hydrolysis product of TBBS, the Maximum Acceptable Toxicant Concentration (MATC) in an early-life stage test on rainbow trout was determined to be 0.041 - 0.078 mg/L within 89 days. The concentration of 0.078 mg/L was reported as LOEC and 0.041 mg/L as NOEC.
- Executive summary:
For benzothiazole-2-thiol as hydrolysis product of TBBS, the Maximum Acceptable Toxicant Concentration (MATC) in an early-life stage test on rainbow trout was determined to be 0.041 - 0.078 mg/L within 89 days. The concentration of 0.078 mg/L was reported as LOEC and 0.041 mg/L as NOEC.
Reference
At the termination of the test, data obtained on embryo viability, survival at hatch, larval survival and larval growth (wet weight and total length) were statistically analysed to establish treatment level effects.
Description of key information
For benzothiazole-2-thiol (MBT) as hydrolysis product of TBBS, the Maximum Acceptable Toxicant Concentration (MATC) in an early-life stage test on rainbow trout was determined to be 0.041 - 0.078 mg/L within 89 days. The concentration of 0.078 mg/L was reported as LOEC and 0.041 mg/L as NOEC.
Key value for chemical safety assessment
Fresh water fish
Fresh water fish
- Dose descriptor:
- NOEC
- Effect concentration:
- 0.041 mg/L
Additional information
For hydrolysable substances used in aquatic ecotox tests, REACH Guidance Document R7b (2017), p. 86 states: :
“Where degradation is rapid (e.g. half-life < 1 hour), the available test data will frequently define the hazard of the degradation products since it will be these that have been tested. These data may be used to classify the parent substance in the normal way.
Where degradation is slower (e.g. half-life > 3 days), it may be possible to test the parent substance and thus generate hazard data in the normal manner using a suitable renewal regime. The subsequent degradation may then be considered in determining whether an acute or chronic hazard class should apply.
Where degradation rates fall between these two, testing of either parent and/or degradates should be considered on a case-by-case basis. “
TBBS hydrolyses with a DT50 of 1.8h (MITI 1996) or 9.53h (Monsanto 1984) thus falling in the category where either parent or degradation product could be tested. In the following considerations are discussed which kind of study is recommended:
1. In the case of the sulphenamide category, a study with the degradation product benzothiazole-2-thiol (MBT) is already available. This study (FELS test) has been performed in accordance similar to an accepted international guideline (OECD 210, FELS test) and has been evaluated as Klimisch 2.
2. There are acute and chronic ecotox studies with MBT and TBBS available. The results are presented in the table below (effect values are based on measured concentrations):
TBBS (mg/L) MBT (mg/L)
Daphnia 48h-EC50 1.3 0.71
Daphnia 21d-NOEC >0.16 0.08
Fish 96h-LC50 1.38 0.73
Fish 14d-LC50 1.02 0.67 (8d-LC50)
Fish 89d NOEC use MBT data 0.048
Algae 72h-EC50 0.071 0.5
72h-NOEC 0.023 0.066
Whereas for algae, TBBS appears to be more toxic, the effect values for TBBS and MBT in acute daphnia and fish exhibit comparable. This can also be seen in the chronic tests in daphnia. These results suggest that TBBS and its degradation product MBT have a similar toxicological profile and no relevant differences in a chronic fish test for TBBS would be expected.
As a conclusion the existing chronic fish test for MBT is sufficient to explain the toxicity of TBBS.
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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