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EC number: 200-543-5 | CAS number: 62-56-6
- 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

Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Freshwater
- Hazard assessment conclusion:
- PNEC aqua (freshwater)
- PNEC value:
- 0.01 mg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
- PNEC freshwater (intermittent releases):
- 0.038 mg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 0.001 mg/L
- Assessment factor:
- 100
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 0.38 mg/L
- Assessment factor:
- 1
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 0.072 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 0.007 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for air
Air
- Hazard assessment conclusion:
- no hazard identified
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- PNEC soil
- PNEC value:
- 2.725 mg/kg soil dw
- Assessment factor:
- 50
- Extrapolation method:
- assessment factor
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- no potential for bioaccumulation
Additional information
As a result of the hazard assessment it can be concluded that thiourea meets the criteria for clasification as dangerous to the environment (Aquatic Chronic 2, H411), but is not considered as PBT/vPvB.
Conclusion on classification
Thiourea does not hydrolyse and is not readily biodegradable. According to EC 1272/2008 (chapter 4.1.2.9) the criteria for rapid degradation are defined as follows:
- ready biodegradability
- BOD (5 days) / COD ≥ 0.5
- Actual degradation (biotic or abiotic) in the aquatic environment by > 70 % within 28 days
- Degradation half-lives with proof of ultimate degradation (full mineralization).
The study conducted by Rheinheimer et al. (1990) could demonstrate that thiourea is actually biodegraded in the aquatic environment, but biodegradation is dependent on the habitat. Overall, biodegradation of thiourea ranged between 28 % (after 70 d of incubation) and 87.3 % (after 14 days of incubation). These figures are not related to primary degradation but reflect mineralisation of thiourea to CO2. As the actual (ultimate!) degradation of thiourea in the aquatic environment can reach or even exceed 70% within 28 days the substance is considered to be rapidly degradable.
Thiourea has no potential for bioaccumulation as the measured log Kow is significantly lower than 3 (measured value: - 0.92).
Acute toxicity values are available for all three trophic levels. The lowest aquatic acute toxicity value is an EC50 (96 h) of 3.8 mg/L (Friesel et al., 1984) as reported for Scenedesmus subspicatus.
Chronic toxicity data are available for algae and daphnia. Daphnia were more sensitive than algae. The 21-day NOEC for reproduction was determined to be 0.1 mg/L.
As chronic toxicity values are available for only two trophic levels, the substance is assessed based on both acute and chronic toxicity data and classified according to the most stringent outcome.
A comparison of the lowest acute toxicity value (EC50, 96 h = 3.8 mg/L) with the environmental classification criteria shows that the substance does not qualify for the classification categories for acute (short-term) aquatic hazards: As the EC50 is not ≤ 1 mg/L classification as category acute 1 is not warranted. In addition, the EC50 is in the range of > 1 to ≤ 10 mg/L. However, since thiourea is rapidly degradable as demonstrated by marine water-sediment simulation studies (Rheinheimer et al., 1990), and has no potential for bioaccumulation, classification as category chronic 2 is not warranted based on data for acute toxicity.
A comparison of the most sensitive chronic toxicity value with the classification categories for rapidly degradable substances, however, results in classification of the substance because the 21-day NOEC for reproduction of Daphnia magna fulfils the classification criterion for category chronic 2 of > 0.01 to ≤ 0.1 mg/L.
The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Based on available data, the test item is not classified and labelled as aquatic short-term (acute) toxicity, but as aquatic ling-term (chronic) toxicity category 2 (H411:"Toxic to aquatic life with long lasting effects") according to Regulation (EC) No 1272/2008 (CLP), as amended for the seventeenth time in Regulation (EU) 2021/849.
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