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EC number: 217-496-1 | CAS number: 1873-88-7
- 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
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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:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- GLP compliance:
- yes
- Analytical monitoring:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 59 µl of the test substance, corresponding to 50 mg, was pipetted below the surface of the Milli-RO-water (tap water purified by reverse osmosis; Millipore Corp., Bedford, Mass., USA) and stirred briefly to mix (5 minutes). Subsequently, synthetic sewage feed and sludge were added. - Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Preparation of inoculum for exposure: Coarsely sieved then washed and diluted with ISO medium.
- Amount suspended solids: 3.8 g/l of sludge, as used for the test - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Post exposure observation period:
- After the 3-hour contact time, a well-mixed sample of the contents was poured into a 300 ml oxygen bottle, and the flask was sealed with an oxygen electrode connected to a recorder, forcing the air out of the vessel. Oxygen consumption was measured and recorded for approximately 10 minutes. During measurement, the sample was not aerated but continuously stirred on a magnetic stirrer.
- Test temperature:
- 20.1 - 20.4°C
- pH:
- 8.2 - 8.3
- Nominal and measured concentrations:
- A loading rate of 100 mg/l was tested in duplicate. Performance of a limit concentration at 100 mg/l is acceptable, because 100 mg/l is far above the water solubility of Decamethyltetrasiloxane and thus exceeds the expected concentration in a Sewage Treatment Plant.
- Details on test conditions:
- TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: All glass, approximately 300 ml oxygen bottles and 1 litre test bottles.
- Aeration: Strong aeration with clean, oil-free air.
- No. of vessels per concentration (replicates): Loading rates of 100 mg/l tested in duplicate.
- No. of vessels per control (replicates): Two replicates.
- No. of vessels per reference (replicates): Three concentrations, each one replicate.
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ion-exchange cartridges (Milli-Q) (Millipore Corp., Bedford, Mass., USA).
- Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Results with reference substance (positive control):
- - Results with reference substance valid? Yes. The EC50 of 3,5-dichlorophenol was in the accepted range of 2 to 25 mg/l
- Validity criteria fulfilled:
- yes
- Conclusions:
- An EC50 value of >100 mg/l for toxicity to microorganisms was determined in a reliable ASRI study conducted according to an appropriate test protocol, and in compliance with GLP.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- See endpoint summary for justification of read-across
- Reason / purpose for cross-reference:
- read-across source
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
Referenceopen allclose all
Controls (C) and Decamethyltetrasiloxane (T): pH, oxygen concentration, oxygen consumption and percentage inhibition of the respiration rate
Flask |
Loading rate (mg/l) |
Oxygen conc. at the start (mg O2/l) |
Oxygen consumption (mg O2/l/h) |
% Inhibition respiration rate |
pH |
Cstart T |
0 |
7.0 |
38 |
- |
8.3 |
Cend T |
0 |
7.9 |
41 |
- |
8.3 |
|
∆ 8% |
|
|||
T 1 |
100 |
5.8 |
41 |
-4¹ |
8.2 |
T 2 |
100 |
6.1 |
40 |
-1¹ |
8.2 |
¹: Negative values indicate stimulation of the respiration rate of the sludge. The values are considered as not significant.
Description of key information
Toxicity to microorganisms: 3 hour EC50 >100 mg/l (ASRI), read-across from a structurally-related substance.
Key value for chemical safety assessment
Additional information
There are no reliable microorganism toxicity data available for H-L3.
A category approach is applied to this endpoint and is detailed in the Siloxane Category report (PFA, 2017). The hypothesis for read-across is that siloxane substances exhibit no evidence of significant toxicity to sewage treatment plant microorganisms. This is consistent with a non-polar narcosis mode of action. Therefore, good quality data for the structurally-related substance, decamethyltetrasiloxane, L4, (CAS 141-62-8), have been read across. H-L3 and L4 are structurally-similar substances, both are linear siloxanes.
H-L3 and L4 are members of the Reconsile Siloxanes Category within which, in general, there is no evidence of significant toxicity to microorganisms.
The table below presents microorganism toxicity data available for substances within the Siloxanes Category.
Table: Microorganism toxicity data for substances within the Reconsile Siloxane Category
CAS |
Name |
Result: E(I) C50 |
Result: NOEC (or EC10/ EC20) |
Guideline Number |
Duration (h) |
Reliability |
540-97-6 |
Dodecamethylcyclohexasiloxane |
>100 mg/l |
|
OECD 209 |
3 |
1 |
541-05-9 |
Hexamethylcyclotrisiloxane |
>100 mg/l |
>100 mg/l |
OECD 209 |
3 |
1 |
541-02-6 |
Decamethylcyclopentasiloxane |
>2000 mg/l |
|
C11 |
3 |
1 |
556-67-2 |
Octamethylcyclotetrasiloxane |
>10 000 mg/l |
|
ISO 8192 (Test for Inhibition of Oxygen Consumption by Activated Sludge) |
3 |
4 (WOE) |
556-67-2 |
Octamethylcyclotetrasiloxane |
Little or no toxicity (24 h): 0.1 g/g solution test mat. based on: reduction in number of viable bacteria |
|
Toxicity toEscherichia coliandStaphylococcus aureusat 37°C for 24 hours |
24 |
4 (WOE) |
107-46-0 |
Hexamethyldisiloxane |
>100 mg/l |
≥100 mg/l |
OECD 209 |
3 |
1 |
141-62-8 |
Decamethyltetrasiloxane |
>100 mg/l |
|
OECD 209 |
3 |
1 |
352230-22-9 |
Siloxanes and Silicones, di-Ph, Ph (trimethylsilyl) oxy |
>1000 mg/l |
≥1000 mg/l |
OECD 209 |
3 |
1 |
2627-95-4 |
1,1,3,3-tetramethyl-1,3-divinyldisiloxane |
>1000 mg/l |
≥1000 mg/l Nitrification control indicated no heterotrophic inhibition of respiration rate |
OECD 209 |
3 |
1 |
2554-06-5 |
2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane |
>1000 mg/l |
≥1000 mg/l Nitrification control indicated no heterotrophic inhibition of respiration rate |
OECD 209 |
3 |
1 |
70131-69-0 |
Silsesquioxanes, Phenyl |
>1000 mg/l |
≥1000 mg/l Nitrification control indicated no heterotrophic inhibition of respiration rate |
OECD 209 |
3 |
1 |
99363-37-8 |
dimethyl, methyl(3-aminopropyl) siloxane, trimethylsiloxy-terminated |
> water soluble fraction |
≥ water soluble fraction |
OECD 209 |
3 |
1 |
71750-79-3 |
dimethyl, (aminoethylaminopropyl) methyl siloxane, trimethylsiloxy-terminated |
> water soluble fraction |
≥ water soluble fraction |
OECD 209 |
3 |
1 |
It is, therefore, considered valid to read-across the results for L4 to fill the data gap for the registered substance. Additional information is given in a supporting report (Peter Fisk Associates, 2017) attached in Section 13 of the IUCLID 6 dossier.
In the study with L4, an activated sludge respiration inhibition 3h EC50value of >100 mg/l was reported.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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