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EC number: 244-182-1 | CAS number: 21056-98-4
- 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
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Study on micro-organisms in soil. However, there is no reason why the sensitivity of soil and aquatic micro-organisms should be considered different
- Principles of method if other than guideline:
- Field study measuring soil microbial enzyme activities and soil mesofauna feeding activity
- GLP compliance:
- no
- Details on sampling:
- Monthly samples were taken in September and October 2994 and from April 2005 to November 2005.
Measurement of microbial enzyme activities and faunal feeding activity was performed in samples taken from the soil upper layer (3-15 cm). - Details on test solutions:
- In September 2004, an aqueous solution of KH2PO3 (7.5 g P per m2) with mud flat soil (42% DM, 2.5 kg per m2) were mixed to a volume of 4 L per m2. The finished dispersion was spread evenly on the soil by a watering can an afterwards superficially rake in.
Control plots received only 4 L tap water per m2.
In April 2005, the application of 7.5 g P per m2 was repeated. - Test organisms (species):
- other: Mud flat soil from the North Sea shoreline near Husum, Germany
- Test type:
- static
- Test temperature:
- ambient temperature throughout the year
- Nominal and measured concentrations:
- Dosing at 7.5 g phosphite per m2 resulted in an initial concentration of 841 mg/kg dw in the first soil samples. After the second application, measurements yielded maximum circa 60 mg phosphite per kg dw.
- Details on test conditions:
- The existing grass sward was removed before the first soil treatment. Afterwards a new grass cover (Lolium perenne) was established.
- Key result
- Duration:
- 420 d
- Dose descriptor:
- other: no significant inhibition
- Effect conc.:
- 7.5 other: g/m²
- Nominal / measured:
- meas. (not specified)
- Conc. based on:
- test mat.
- Basis for effect:
- other: enzyme activities
- Remarks on result:
- other: Initial concentration peaked at 840 mg/kg soil, after repeated application the maximum reached 60 mg/kg dw soil.
- Details on results:
- Phosphite concentrations increased in the phosphiet treated plots and after the first phosphite application, the phosphate concentrations increased, after a lag phase. After the second phosphite treatment in April 2005 no delay was observed, oxidation of phosphite restarted immediately. This could be a sign of a well-adapted microbial community.
- Validity criteria fulfilled:
- not applicable
- Conclusions:
- Phosphite applied in a mud flat soil suspension to soil was oxidised to phosphate after a lag phase. No significant correlations were found between microbial enzyme activitues and soil phosphite content. It was concluded that phosphite did not harm the biocoenosis of micro-organisms. This study demonstrates the insensitivity of a generic microbial population to phosphonic acid. The organic material originated from an aquatic environment (mud flat soil) and thus the study can be used to fulfil the current data requirement.
- Executive summary:
The effect of phosphite on the microbial biocoenosis of an arable soil was investigated in a field trial. The response of soil micro-organisms was studied. After application of phoshite in the form of KH2PO3, combined with nud-flat soil, to the upper layer of a grass grown plot, an adaptation of the metabolic acitvity of the active soil biocoenosis caused at least a partly oxidation of phosphite to phosphate. Initial concentrations reached up to 840 mg/kg soil dw, whereas after repeated dosing the concentration reached 60 mg/kg soil dw as apparently the microflora was capable to tranform phosphite into phosphates.
Microbial enzyme activities demonstrated no significant correlation to soil contents of phosphite and phosphate with exception of dehydrogenase (correlated to phosphate) which was increased. Thus no toxic effects were observed. This study demonstrates the insensitivity of a generic microbial population to phosphonic acid. The organic material originated from an aquatic environment (mud flat soil) and thus the study can be used to fulfil the current data requirement.
Reference
The microbial enzyme activity of dehydrogenase and alkaline phosphatase were significantly increased in the phosphite treated soils, by 21 and 28%, respectively.
The cellulase activity was decreased by 16% (not significant), while the protease activity remained contstant.
Description of key information
Potassium phosphite (KH2PO3) caused no enzyme inhibition on the microflora from arable soil/mud flat soil (North Seashore) mixture. Dose rates were > 840 and > 60 mg/kg soil dw. No toxicity to microorganisms is expected.
Key value for chemical safety assessment
Additional information
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