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EC number: 212-783-8 | CAS number: 868-85-9
- 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:
- 24.8 µg/L
- Assessment factor:
- 1 000
- Extrapolation method:
- assessment factor
- PNEC freshwater (intermittent releases):
- 248 µg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 2.48 µg/L
- Assessment factor:
- 10 000
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 1 000 mg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 54.01 µg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 5.4 µg/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:
- 4.56 µg/kg soil dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- no potential for bioaccumulation
Additional information
Conclusion on classification
Ecotoxicological classification of dimethyl phosphonate cannot be determined unequivocally on the basis of data available and may need further discussion and investigations, especially on the hydrolysis product monomethyl phosphonate.
An important characteristic of dimethyl phosphonate is that it is hydrolysed in water with a half-life strongly depending on the pH. According to the “Guidance on the Application of the CLP criteria” (ECHA, 2009) hydrolysis half-life must be considered between pH values of 4 to 9. The longest hydrolysis half-life of dimethyl phosphonate was found to be 470 h (19.6 d) at pH 4 (Bayer AG, 2002) which indicates that the substance can remain in water for more than 12 h and therefore dimethyl phosphonate itself and not its hydrolysis products should be considered for classification. Nevertheless dimethyl phosphonate is hydrolysed significant faster at pH 7 and pH 9 with half-lifes of 3 h and less than 1 min, respectively.
Tests on biodegradation, which are supposed to be conducted at neutral pH, revealed dimethyl phosphonate itself to disappear up to 86% during 28 days based on analysis of dimethyl phosphonate itself (MITI, 1992). Dimethyl phosphonate elimination is based primarily on hydrolysis. Measurements on DOC, BOD and TOC showed that only 50% of the initial carbon attributed to dimethyl phosphonate was mineralised during the biodegradation tests while half of the initial carbon remained in solution (Bayer AG, 1992; MITI, 1992). Since dimethyl phosphonate disappeared up to 86% and the hydrolysis product methanol is readily biodegradable, most of the remaining carbon is likely to be attributed to the hydrolysis product monomethyl phosphonate. According to the “Guidance on the Application of the CLP criteria” (ECHA, 2009) hydrolysis can only be used as an argument for ready biodegradation “when the longest half-life t1/2 determined within the pH range 4-9 is shorter than 16 days” and “only when it can be satisfactorily demonstrated that the hydrolysis products formed do not fulfil the criteria for classification as hazardous for the aquatic environment”. Since both criteria are not fulfilled and measured BOD- and DOC values only reached 50% dimethyl phosphonate is considered not to be readily biodegradable.
Based on calculated very low log Kow values dimethyl phosphonate and its hydrolysis products are not expected to accumulate in biota.
In aquatic toxicity tests a toxic effect on the crustacean Daphnia magna was found (Bayer AG, 2003). After 48 h a nominal EC50 of 24.8 mg/L was determined. Due to hydrolysis dimethyl phosphonate concentrations dropped down below its detection limit during the test, whereas significant monomethyl phosphonate concentrations (22 – 35% w/w of initial dimethyl phosphonate) were present throughout the whole exposure period. During hydrolysis of dimethyl phosphonate the hydrolysis products formed are methanol, phosphonic acid and monomethyl phosphonate. Methanol and phosphonic acid are known not to be toxic to the environment. Information is available on both substances. In contrast, no data is available on toxicity of monomethyl phosphonate. Since it is not obvious whether the effect on Daphnia magna is caused by dimethyl phosphonate or monomethyl phosphonate, a toxic effect of dimethyl phosphonate cannot be excluded. For security reasons it was decided to classify dimethyl phosphonate with R52/53 according to 67/548/EEC and with aquatic chronic category 3, H412 according to CLP. A classification of dimethyl phosphonate could be avoided if data would be available on monomethyl phosphonate which indicate a toxic effect of this substance on Daphnia magna or if long-term studies of dimethyl phosphonate on Daphnia magna would be available which indicate a NOEC > 1 mg/L.
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