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EC number: 231-545-4 | CAS number: 7631-86-9
- 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
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
- Study period:
- 15 May 2019 to 22 May 2019 (experimental phase)
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))
- Version / remarks:
- 2010
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
- Version / remarks:
- 2015
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Analytical monitoring:
- no
- Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test item was pipetted directly into the test vessels;
- Controls: yes, maintained under identical conditions but not exposed to test item. - Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Pretreatment:
Upon arrival in the test facility, the sludge was filtrated, washed with tap water 3 times and re-suspended in tap water. The activated sludge was aerated until usage in the test and fed daily with 50 mL synthetic sewage feed /L
- The dry matter was determined as 3.1 g suspended solids/L, giving a concentration of 1.55 g suspended solids/L in the test. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 3 h
- Post exposure observation period:
- no
- Hardness:
- 0.88 mM
- Test temperature:
- 18.5 – 20.9 °C
- pH:
- 8.2-8.3 (controls 8.3)
- Salinity:
- not appplicable
- Conductivity:
- 210 µS/cm
- Nominal and measured concentrations:
- 2.5, 25, 250 and 2500 mg/L (nominal, corresponding to 1, 10, 100 and 1000 mg/L SiO2 in the test item)
- Details on test conditions:
- TEST SYSTEM
- Test vessel: Glass beakers (800 – 1000 mL) were used as test vessels.Narrow-neck glass bottles with flat bottoms (250 mL) were used for O2 measurements.
- Aeration: purified air, using Pasteur pipettes;
- No. of vessels per concentration (replicates): 1 (lower concentrations), 5 (highest concentration)
- No. of vessels per control (replicates): 1 (positive control), 2 before and 2 after measuring positive control and test item, respectively.
- No. of vessels per abiotic control (replicates): -
TEST WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water, CoA available;
SYNTHETIC SEWAGE
- as per guideline;
EFFECT PARAMETERS MEASURED: oxygen consumption after 3 hours; - Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol
- Key result
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 2 500 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Remarks on result:
- other: value corresponds to >1000 mg SiO2/L
- Key result
- Duration:
- 3 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 2 500 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Remarks on result:
- other: value corresponds to 1000 mg SiO2/L
- Details on results:
- Validity criteria were fulfilled:
- The coefficient of variation of oxygen uptake rate in control replicates was +/- 6.9% (i.e. less than 30%)
- The mean specific respiration rate of the blank controls was 27.61 mg oxygen per gram dry weight of sludge per hour (i.e. was > 20 mg oxygen per gram dry weight of sludge per hour).
- The reference substance results were valid, the EC50 for 3,5-dichlorophenol was within the expected range: 2 to 25 mg/L. - Results with reference substance (positive control):
- Results with reference substance valid: yes
- 3,5-dichlorophenol, EC50 (3 hours): 10 mg/L (95% CI 5.4-15 mg/L); - Reported statistics and error estimates:
- For the treatments with the test item concentration 2500 mg/L (corresponding to 1000 mg SiO2/L), it was tested whether the differences between treatment and blank control were significant. Based on equality of variance, the t-test was used (level of significance: 95%).
- Validity criteria fulfilled:
- yes
- Conclusions:
- The effect of the test item on the respiration of activated sewage sludge resulted in a 3 -hour EC50 of > 2500 mg/L (corresponding to 1000 mg SiO2/L). The No Observed Effect Concentration (NOEC) after 3 hours exposure was 2500 mg/L (corresponding to 1000 mg SiO2/L)
- Executive summary:
A GLP study was performed to assess the effect of the test item on the respiration of activated sewage sludge. The method followed that described in the OECD Guidelines for Testing of Chemicals No 209, adopted in 2010 and Commission Regulation (EU) No. 2016/266 amending Regulation (EC) No. 440/2008, EU-Method C.11., adopted in 2015. Activated sewage sludge from a mainly domestic sewage treatment plant was exposed to the test item at concentrations of 2.5, 25, 250, and 2500 mg/L (corresponding to 1, 10, 100 and 1000 mg SiO2/L) at a temperature of 20 +/- 2 °C for a period of 3 hours with the addition of synthetic sewage as respiratory substrate. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference material, 3,5-dichlorophenol. The effect of the test item on the respiration of activated sewage sludge resulted in a 3 -hour EC50 of > 2500 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 2500 mg/L (corresponding to 1000 mg SiO2/L).
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 14 January 2020 to 15 January 2020
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- Version / remarks:
- July 22, 2010
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Specific details on test material used for the study:
- Customer grade: S-17D
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Pretreatment:
Upon arrival in the test facility, the sludge was washed with reconstituted water and centrifuged. The supernatnt was decanted after centrifugation of the sludge and this washing procedures was performed at least twice. The activated sludge was aerated until usage in the test and fed daily with 50 mL synthetic sewage feed /L.
- The dry matter was determined as 3.75 g suspended solids/L (± 10%), giving a concentration of 1.5 g suspended solids/L (± 10%) in the test. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Test temperature:
- 18.2–19.8 °C
- pH:
- 7.4 (definitive test); 7.4-7.5 (reference test)
- Nominal and measured concentrations:
- Limit test: 1000 mg/L (nominal)
- Details on test conditions:
- The test solutions were stirred at test temperature for 24±1 hours before start of exposure to yield a suspension.
- Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol (3,5-DCP)
- Key result
- Duration:
- 3 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Key result
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Details on results:
- - Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: after stirring, the test solution appeared as a homogeneous, slightly turbid suspension.
- Effect concentrations exceeding solubility of substance in test medium: solubility was exceeded;
- Adsorption (e.g. of test material to the walls of the test container): none reported
- Blank controls oxygen uptake rate: 60.8 and 48.8 mg O2/L.h
- Coefficient of variation of oxygen uptake rate in 3 control replicates: 14.9 and 3.8
- Results with reference substance (positive control):
- Results with the reference substance were valid. The EC50 for 3,5-dichlorophenol was determined to be 7.10 mg/L (acceptable range: 2- 5 mg/L)
- Reported statistics and error estimates:
- The EC50 of the reference substance was calculated with probit analysis (i.e. cumulative distribution function (CDF) using a non-linear regression without weighting) using the softwareToxRat Professional 3.3.0.
- Validity criteria fulfilled:
- yes
- Conclusions:
- The definitive (limit) test showed no inhibition of total respiration rate of the inoculum at 1000 mg test item/L compared to the control respiration. The EC50 is therefore expressed as > 1000 mg test item/L.
- Executive summary:
The study was conducted according to OECD test guideline 209 (2010) as a limit test. The test substance did not show no inhibition of total respiration ratea at 1000 mg/L. The 3 hour EC50 of the test substance was calculated as >1000 mg/L. Thus the NOEC was determined to be 1000 mg/L.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 14 January 2020 to 15 January 2020
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- Version / remarks:
- July 22, 2010
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Pretreatment:
Upon arrival in the test facility, the sludge was washed with reconstituted water and centrifuged. The supernatnt was decanted after centrifugation of the sludge and this washing procedures was performed at least twice. The activated sludge was aerated until usage in the test and fed daily with 50 mL synthetic sewage feed /L.
- The dry matter was determined as 3.75 g suspended solids/L (± 10%), giving a concentration of 1.5 g suspended solids/L (± 10%) in the test. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Test temperature:
- 18.2–19.8 °C
- pH:
- 7.4 (definitive test); 7.4-7.5 (reference test)
- Salinity:
- not appplicable
- Nominal and measured concentrations:
- Limit test: 1000 mg/L (nominal)
- Details on test conditions:
- The test solutions were stirred at test temperature for 24±1 hours before start of exposure to yield a suspension.
- Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol (3,5-DCP)
- Key result
- Duration:
- 3 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Key result
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Details on results:
- - Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: after stirring, the test solution appeared as a homogeneous, slightly turbid suspension.
- Effect concentrations exceeding solubility of substance in test medium: solubility was exceeded;
- Adsorption (e.g. of test material to the walls of the test container): none reported
- Blank controls oxygen uptake rate: 60.8 and 48.8 mg O2/L.h
- Coefficient of variation of oxygen uptake rate in 3 control replicates: 14.9 and 3.8
- Results with reference substance (positive control):
- Results with the reference substance were valid. The EC50 for 3,5-dichlorophenol was determined to be 7.10 mg/L (acceptable range: 2- 5 mg/L)
- Reported statistics and error estimates:
- The EC50 of the reference substance was calculated with probit analysis (i.e. cumulative distribution function (CDF) using a non-linear regression without weighting) using the softwareToxRat
Professional 3.3.0. - Validity criteria fulfilled:
- yes
- Conclusions:
- The definitive (limit) test showed no inhibition of total respiration rate of the inoculum at 1000 mg test item/L compared to the control respiration. The EC50 is therefore expressed as > 1000 mg test item/L.
- Executive summary:
The study was conducted according to OECD test guideline 209 (2010) as a limit test. The test substance did not show no inhibition of total respiration ratea at 1000 mg/L. The 3 hour EC50 of the test substance was calculated as >1000 mg/L. Thus the NOEC was determined to be 1000 mg/L.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 14 January 2020 to 15 January 2020
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- Version / remarks:
- July 22, 2010
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Pretreatment:
Upon arrival in the test facility, the sludge was washed with reconstituted water and centrifuged. The supernatnt was decanted after centrifugation of the sludge and this washing procedures was performed at least twice. The activated sludge was aerated until usage in the test and fed daily with 50 mL synthetic sewage feed /L.
- The dry matter was determined as 3.75 g suspended solids/L (± 10%), giving a concentration of 1.5 g suspended solids/L (± 10%) in the test. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Test temperature:
- 18.2–19.8 °C
- pH:
- 7.4 (definitive test); 7.4-7.5 (reference test)
- Salinity:
- not appplicable
- Nominal and measured concentrations:
- Limit test: 1000 mg/L (nominal)
- Details on test conditions:
- The test solutions were stirred at test temperature for 24±1 hours before start of exposure to yield a suspension.
- Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol (3,5-DCP)
- Key result
- Duration:
- 3 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Key result
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Details on results:
- - Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: after stirring, the test solution appeared as a homogeneous, slightly turbid suspension.
- Effect concentrations exceeding solubility of substance in test medium: solubility was exceeded;
- Adsorption (e.g. of test material to the walls of the test container): none reported
- Blank controls oxygen uptake rate: 60.8 and 48.8 mg O2/L.h
- Coefficient of variation of oxygen uptake rate in 3 control replicates: 14.9 and 3.8
- Results with reference substance (positive control):
- Results with the reference substance were valid. The EC50 for 3,5-dichlorophenol was determined to be 7.10 mg/L (acceptable range: 2- 5 mg/L)
- Reported statistics and error estimates:
- The EC50 of the reference substance was calculated with probit analysis (i.e. cumulative distribution function (CDF) using a non-linear regression without weighting) using the softwareToxRat Professional 3.3.0.
- Validity criteria fulfilled:
- yes
- Conclusions:
- The definitive (limit) test showed no inhibition of total respiration rate of the inoculum at 1000 mg test item/L compared to the control respiration. The EC50 is therefore expressed as > 1000 mg test item/L.
- Executive summary:
The study was conducted according to OECD test guideline 209 (2010) as a limit test. The test substance did not show no inhibition of total respiration ratea at 1000 mg/L. The 3 hour EC50 of the test substance was calculated as >1000 mg/L. Thus the NOEC was determined to be 1000 mg/L.
Referenceopen allclose all
Description of key information
For the assessment of the aquatic toxicity of synthetic amorphous silica (SAS) to microgranisms, the database compiles 4 studies from 2019 and 2020. All these studies were conducted according to OECD TG 209 and EC guidelines under GLP. In conclusion none of the examined test items did show a relevant respiratory inhibition to microorganisms up to and including the highest tested concentration of 1000 mg/L (tested as suspensions).
Key value for chemical safety assessment
Additional information
EC50 value was not determined in all studies within the range of test concentrations up to and including the concentration limit of 1000 mg/L recommended in the current OECD TG 209.
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