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EC number: 603-758-6 | CAS number: 133647-88-8
- 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
Endpoint summary
Administrative data
Description of key information
Additional information
Validity of the read-across
The aquatic toxicity of sodium (2R)-2-(4-hydroxyphenoxy)propanoate (CAS 133647-88-8) was determined by read-across from aquatic toxicity studies conducted with the free acid, namely (R)-2-(4-hydroxyphenoxy)propanoic acid (CAS 94050-90-5).
This read-across is valid as all tests were performed in aqueous solutions where the sodium salt of the acid normally dissociates into sodium cations and the free acid anion.
Regarding the pKa of (R)-2-(4-hydroxyphenoxy)propanoic acid of 3.32 it can be assumed that the acid, when dissolved in water under environmental relevant concentrations (pH > 4), will instantly be deprotonated and become the same acid anion as after dissociation of the sodium salt. As in the experiments (R)-2-(4-hydroxyphenoxy)propanoic acid showed no alteration of the test medium pH it can be assumed that also the sodium salt should not cause greater changes in test medium pH.
The additional sodium ions dissociating from the salt should have no further impact on aquatic toxicity. Compared to the highest test item concentrations of 100 mg/L (0.5 mmol/L for the sodium salt) the sodium levels in the OECD recommended test media for fish and daphniae are already 70% higher (0.85 mmol/L).
At the highest tested concentration of (R)-2-(4-hydroxyphenoxy)propanoic acid (100 mg/L), the molar concentration of the acid is 0.55 mmol/L. Due to the different molar weight of the sodium salt, the limit concentration of 100 mg/L corresponds to a lower molar concentration of only 0.5 mmol/L for the sodium salt. It can therefore be concluded that estimation of toxicity from the acid to the sodium salt is quite conservative.
Aquatic toxicity of (R)-2-(4-hydroxyphenoxy)propanoic acid
The aquatic toxicity tests of (R)-2-(4-hydroxyphenoxy)propanoic acid were assessed on the organisms fish, daphniae, algae and bacteria.
In an acute fish-toxicity study, the NOEC was found to be 100 mg/L (Rufli 1995). Immobilisation of daphnids was visible only at 100 mg/L, with 58 mg/L being the NOEC (Neumann 1996). Algal growth was also reduced not until 100 mg/L with a NOEC of 46 mg/L (Memmert 1996). Inhibition of bacterial respiration was in all concentrations ≤ 15% with no visible dose response (Grade 1996). The respective LC50/EC50 values were all > 100 mg/L.
Based on the aforementioned results and applying the classification criteria according to the Regulation (EC) No 1272/2008, Annex I, Part 4, 4.1.2.6, the test item (R)-2-(4-hydroxyphenoxy)propanoic acid is not classified as hazardous to the aquatic environment.
Aquatic toxicity of sodium (2R)-2-(4-hydroxyphenoxy)propanoate
As stated above, sodium (2R)-2-(4-hydroxyphenoxy)propanoate, when dissolved in water becomes equal to the test item (R)-2-(4-hydroxyphenoxy)propanoic acid. It can therefore be assumed that the aquatic toxicity of the potassium salt is equal to the aquatic toxicity of the acid. It is therefore highly likely that sodium (2R)-2-(4-hydroxyphenoxy)propanoate can also be considered to be not hazardous to the aquatic environment.
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