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EC number: 231-967-9 | CAS number: 7782-87-8
- 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
Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: GLP guideline study (OECD)
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 111 (Hydrolysis as a Function of pH)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Radiolabelling:
- no
- Analytical monitoring:
- yes
- Details on sampling:
- Before and after incubation at 50 °C, 50 µL aliquots of the test solutions at each pH value were analyzed after 1:100 dilution with water by IC separation of the injected sample solution.
- Buffers:
- - Composition of buffer:
The buffer solutions, pH 4.0, 7.0 and 9.0, were prepared as recommended by the OECD guideline 111. The authors do not precise the buffer system, but according to the main substance used in the buffer solution cited by the authors we can conclude they used the buffer mixtures of Clark and Lubs (Annex 3 of the OECD guideline).
- Details of composition (according to guideline):
Buffer pH 4.0: 0.40 ml. 0.1 N NaOH +50 ml. biphthalate to 100 ml
Buffer pH 7.0: 29.63 ml. 0.1 N NaOH + 50 ml. phosphate to 100 ml
Buufer pH 9.0: 21.30 ml. 0.1 N NaOH + 50 ml. boric acid to 100 ml - Details on test conditions:
- The test item was dissolved in an aqueous solution at a specific pH value (pH 4.0, pH 7.0 and pH 9.0).
Test item at pH 4.0: 581.34 mg of Sodium Hypophosphite (Solid) were dissolved in 100 mL of buffer solution (pH 4.0) to prepare a test solution of 5.8134 mg/mL Sodium Hypophosphite (Solid).
Test item at pH 7.0: 590.52 mg of Sodium Hypophosphite (Solid) were dissolved in 100 mL of buffer solution (pH 7.0) to prepare a test solution of 5.9052 mg/mL Sodium Hypophosphite (Solid).
Test item at pH 9.0: 548.49 mg of Sodium Hypophosphite (Solid) were dissolved in 100 mL of buffer solution (pH 9.0) to prepare a test solution of 5.4849 mg/mL Sodium Hypophosphite (Solid).
After preparation the solution was incubated in the dark and at a specific temperature in a water bath thermostated at the specific temperature with a maximum deviation of ± 0.5 °C. The concentration of the test item was determined as a function of time, using a suitable analytical method. Major hydrolysis products representing more than 10 % of the applied dose should be identified.
Preliminary test : performed at 50 °C ± 0.5 °C at each of pH 4.0, pH 7.0 and pH 9.0. Aliquots of each test solution were analyzed before incubation, after 2.4 hours and after 120 hours.
As no degradation was observed, sterility tests were not considered as needed.
TEST SYSTEM
- Type, material and volume of test flasks: 50 mL Erlenmeyer flasks. All glassware and flasks rinsed with sterile buffer and stopperedwith inert material
- Sterilisation method: buffered solutions and milliQ water autoclaved for 25 min before first use
- Lighting: test solution protected from direct light
- Measures to exclude oxygen: nitrogen bubbling for 10 min before preparation of solution + seal flasks
TEST MEDIUM
- Volume used/treatment : 50 mL
- Kind and purity of water: milliQ water
- Preparation of test medium: 581.34 mg of Sodium Hypophosphite (Solid) were dissolved in 100 mL of buffer solution (pH 4.0)
- Renewal of test solution:
- Identity and concentration of co-solvent: - Duration:
- 120 h
- pH:
- 4
- Temp.:
- 50 °C
- Duration:
- 120 h
- pH:
- 7
- Temp.:
- 50 °C
- Duration:
- 120 h
- pH:
- 9
- Temp.:
- 50 °C
- Number of replicates:
- 2
- Preliminary study:
- Less than 10% of hydrolysis was observed at every pH tested.
As no degradation was observed, sterility tests were not considered as needed.
A main study was not required, as the test item was found to be stable according to the criteria given in the guideline. - Transformation products:
- not specified
- % Recovery:
- 95.8 - 96.1
- pH:
- 4
- Temp.:
- 50 °C
- Duration:
- 120 h
- % Recovery:
- 99.8 - 100.9
- pH:
- 7
- Temp.:
- 50 °C
- Duration:
- 120 h
- % Recovery:
- 98.2 - 99.8
- pH:
- 9
- Temp.:
- 50 °C
- Duration:
- 120 h
- pH:
- 4
- Temp.:
- 25 °C
- DT50:
- > 1 yr
- Type:
- not specified
- Remarks on result:
- other: <10% hydrolysis after 5 days at 50°C
- pH:
- 7
- Temp.:
- 25 °C
- DT50:
- > 1 yr
- Type:
- not specified
- Remarks on result:
- other: <10% hydrolysis after 5 days at 50°C
- pH:
- 9
- Temp.:
- 25 °C
- DT50:
- > 1 yr
- Type:
- not specified
- Remarks on result:
- other: <10% hydrolysis after 5 days at 50°C
- Validity criteria fulfilled:
- yes
- Conclusions:
- In the test conditions, the tests at pH 4.0, pH 7.0 and pH 9.0 showed no significant degradation of Sodium Hypophosphite (Solid) at 50 °C. The hydrolysis of Sodium Hypophosphite (Solid) was less than 10% after 5 days.
Therefore, the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, Sodium Hypophosphite (Solid) is considered to be hydrolytically stable, and no further testing was necessary. - Executive summary:
Hydrolysis as function of pH of Sodium Hypophosphite (solid) as been determined according to OECD guideline 111 under GLP procedure.
Preliminary study was conducted in duplicate at pH 4.0, 7.0 and 9.0 at a temperature of 50°C. Concentration in the test substance was measured by ion chromatography before the test after 2.4 hours and 120h (5 days) of incubation under no direct light and avoiding oxygen.
In the test conditions, the tests at pH 4.0, pH 7.0 and pH 9.0 showed no significant degradation of Sodium Hypophosphite (Solid) at 50 °C. The hydrolysis of Sodium Hypophosphite (Solid) was less than 10% after 5 days.
As no degradation was observed, sterility tests were not considered as needed.
Therefore, the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, Sodium Hypophosphite (Solid) is considered to be hydrolytically stable, and no further testing was necessary.
This study is considered as reliable without restriction.
Reference
Table1 Results of the Preliminary Test of Sodium Hypophosphite (Solid)
|
Initial concentration measured |
Concentration measured after 2.4 hours incubation |
Concentration measured after 5 days incubation |
Hydrolysis reaction after 5 days incubation |
Recovery |
|
[mg/mL] |
[mg/mL] |
[mg/mL] |
[%] |
[%] |
pH 4.0 |
5.588 |
5.627 |
5.218 |
7 |
96.1 |
5.570 |
5.773 |
5.114 |
8 |
95.8 |
|
pH 7.0 |
5.892 |
5.590 |
6.144 |
-4 |
99.8 |
5.961 |
5.515 |
6.425 |
-8 |
100.9 |
|
pH 9.0 |
5.472 |
5.396 |
5.396 |
1 |
99.8 |
5.385 |
5.489 |
5.380 |
0 |
98.2 |
Description of key information
Hydrolysis of sodium phosphinate at
pH 4, 50°C, 120h: < 10% (OECD guideline 111)
pH 7, 50°C, 120h: < 10% (OECD guideline 111)
pH 9, 50°C, 120h: < 10% (OECD guideline 111)
Therefore, the estimated half-life time is higher than one year under representative environmental conditions (25 °C) and sodium phosphinate is considered to be hydrolytically stable. By read-across, potassium phosphinate is expected to be hydrolytically stable as well.
Key value for chemical safety assessment
Additional information
The study of Habeck (2009) was chosen as key study since it is reliable without restriction (Klimisch 1; GLP guideline study). Hydrolysis as function of pH of sodium phosphinate was determined according to OECD guideline 111 under GLP procedure. A preliminary study at pH 4.0, 7.0 and 9.0 and at a temperature of 50°C measured the concentration of the test substance before the test and after 2.4 hours and 120 hours (5 days) of incubation under no direct light and avoiding oxygen. Under these conditions no significant degradation of sodium phosphinate was observed at 50 °C for all tested pH-values. After 5 days the hydrolysis of sodium phosphinate was less than 10%.
The estimated half-life time is higher than one year under representative environmental conditions. Therefore, sodium phosphinate is considered to be hydrolytically stable.
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