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EC number: 219-863-1 | CAS number: 2554-06-5
- 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:
- supporting study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
- Version / remarks:
- Cited as Directive 88/302/EEC, C.11
- GLP compliance:
- yes
- Analytical monitoring:
- no
- Test organisms (species):
- activated sludge, domestic
- Details on inoculum:
- Activated sludge was from the sewage treatment plant Marl-West (Lippeverband), treating predominantly domestic sewage.
Content of suspended solids: 3.01 g/l (activated sludge). This gives a concentration of 1203 mg/l in the test medium. - Test type:
- static
- Total exposure duration:
- 3 h
- Test temperature:
- Temperature: 18-22 deg C.
At the beginning of the incubation: 18.0 - 18.5 deg C;
during the determination of oxygen content: 18.5 - 19.5 deg C. - Dissolved oxygen:
- Oxygen consumption:
Control 1: 29.92 mg O2/l*h
Control 2: 31.60 mg O2/l*h
The difference between control 1 and 2 does not exceed 15% (5.3%). - Nominal and measured concentrations:
- Nominal: 125, 250, 55, 1000, and 2000 mg a.i./L
Measured: 124.8; 250; 499.8; 1000.4 and 2000.2 mg a.i./L - Details on test conditions:
- Type: aquatic
- Reference substance (positive control):
- yes
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 2 000 mg/L
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Details on results:
- In the tested concentration range of 124.8; 250; 499.8; 1000.4 and 2000.2 mg/l there was no inhibition of
respiration of activated sludge. EC50 > 2000 mg/l rounded up two significant places and calculated as active
substance. - Results with reference substance (positive control):
- Reference substance: 3,5 Dichlorophenol, 5, 15, 30 mg/l.
EC50 - limit: 5-30 mg/l; EC50-determined: 6.5 mg/l. - Conclusions:
- An ASRI 3hr EC50 of >2000 mg/l was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- 2009-11-12
- 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
- Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 50 mg of the test substance was added to 250ml of purified tap water and stirred. - Test organisms (species):
- activated sludge
- Details on inoculum:
- - Source: Municipal sewage treatment plant: ‘Waterschap de Maaskant', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage
- Preparation of inoculum for exposure: coarsely sieved then washed. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Post exposure observation period:
- Oxygen consumption was measured and recorded for approximately 10 minutes.
- Test temperature:
- 19.8-20.0°C
- pH:
- 7.4
- Nominal and measured concentrations:
- 100 mg/L
- Details on test conditions:
- TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 1L test bottle
- Aeration: continuous vigorous aeration during contact time
- No. of vessels per concentration (replicates): Two
- No. of vessels per control (replicates): One at the initial, one at the final test points.
- Biomass loading rate: activated sludge: 4.0 g/l
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.).
- Reference substance (positive control):
- yes
- Remarks:
- 3,5-Dichlorophenol
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Details on results:
- The two control had a difference in respiration rate of 8%, which is the limit for a valid study.
- Results with reference substance (positive control):
- A positive control test with 3,5-dichlorophenol yielded an EC50 of 7.7 mg/L. The validity criteria of the Guideline were fulfilled.
- Validity criteria fulfilled:
- yes
- Conclusions:
- An EC50 >100 mg/l for toxicity to microorganisms was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 09 February 2012 - 09 February 2012
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Analytical monitoring:
- no
- Vehicle:
- no
- Details on test solutions:
- The batch of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane tested was a clear colourless liquid with a purity of 97.41% ±0.01. Since 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane may have the potential to be volatile (information obtained by the sponsor), the test substance was pipetted below the surface of Milli-RO-water (200 ml, tap water purified by reverse osmosis) and stirred briefly to mix (5 minutes) in closed dark brown bottles. The initial loading rates were 2.5 times the final loading rate. Subsequently, 16 ml synthetic medium, 250 ml sludge and Milli-RO water up to 500 ml were added resulting in the required loading rates. Optimal contact between the test substance and test organisms was ensured applying continuous aeration and stirring.
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- The sludge was coarsely sieved, washed and diluted with ISO-medium. A small amount of the sludge was weighed and dried overnight at ca. 105°C to determine the amount of suspended solids (3.0 g/l of sludge, as used for the test). The pH was 7.4 on the day of testing. The batch of sludge was used one day after collection; therefore 50 ml of synthetic medium was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.
- 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, the oxygen consumption was recorded for a period of approximately 10 minutes. During measurement, the sample was not aerated but continuously stirred on a magnetic stirrer. The pH and temperature were determined in the remaining part of the reaction mixture.
- Test temperature:
- Between 18.0 and 19.6°C.
- pH:
- Before addition of sludge: 7.6 - 7.7
After the 3 hour exposure period: 7.5 - 8.3 - Dissolved oxygen:
- The oxygen concentration at the start of measurements was at least 7.5 mg O2/l
Controls: 48 mg O2/l h
2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane 10 mg/l: 50 mg O2/l h
2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane 100 mg/l: 52 mg O2/l h
2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane 1000 mg/l: 50 mg O2/l h - Nominal and measured concentrations:
- Nominal loading rates: 10, 100 and 1000 mg/l
- Details on test conditions:
- TEST SYSTEM
- Type: open
- Material, size, headspace, fill volume: All glass
- Aeration:During exposure with clean, oil-free air
- No. of vessels per concentration (replicates): 1 for 10 and 100 mg/l and 3 for 1000 mg/l
- No. of vessels per control (replicates): 2
- Biomass loading rate: 1.5 g/l suspended solids in final test mixture
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis (Milli-RO
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The respiration rate from each vessel, in mg O2/l/hr, was calculated from the linear part of the respiration curve, which was generally between 2 and 7 mg O2/l.
TEST CONCENTRATIONS
- Test concentrations: combined limit/range-finding test at 10, 100 and 1000 mg/l (loading rates) - Reference substance (positive control):
- yes
- Remarks:
- 3,5-dichlorophenol
- Duration:
- 3 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Remarks:
- (loading rate)
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Remarks:
- (loading rate)
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Details on results:
In the combined limit/range-finding test no statistically significant inhibition of the respiration rate of the sludge was recorded at a loading rate of 1000 mg 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane per litre (Two Sample t-Test : α=0.05 Toxstat).
There was no oxygen uptake from abiotic processes and the results at 1000 mg/l with a nitrification inhibitor showed no heterotrophic inhibition of the respiration rate.- Results with reference substance (positive control):
- The EC50 of 3,5-dichlorophenol was in the accepted range of 2 to 25 mg/l for total respiration (4.0 mg/l).
- Reported statistics and error estimates:
- ECx
For the reference substance the percentage inhibition was plotted against the logarithm of the concentrations and the EC50 was determined using linear regression analysis.
For 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane no EC50 could be calculated because the test substance proved to be non-toxic (EC50 > a loading rate of 1000 mg/l).
NOEC estimation
The NOEC was based on statistical analysis of the data. Data obtained for the test concentrations were compared with those obtained for the control using TOXSTAT Release 3.5, 1996, D.D. Gulley, A.M. Boelter, H.L. Bergman. - Validity criteria fulfilled:
- yes
- Conclusions:
- Under the conditions of this present test 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was not toxic to waste water (activated sludge) bacteria up to and including a loading rate of 1000 mg/l (NOEC).
The EC50 exceeded a loading rate of 1000 mg/l.
Referenceopen allclose all
Table 1: Controls, reference substance (3, 5-dichlorophenol) and test substance (D5): oxygen consumption and percentage inhibition of the respiration rate.
Flask |
Nominal concentration (mg/l) |
Oxygen consumption (mg O2/l/hour) |
% Inhibition respiration rate |
Control (average of two) |
0 |
30.76 |
- |
|
|||
Test substance |
2000.2 |
30.71 |
0.2 |
Test substance |
1000.4 |
31.97 |
-3.9 |
Test substance |
499.8 |
32.88 |
-6.9 |
Test substance |
250 |
32.29 |
-5.0 |
Test substance |
124.8 |
31.54 |
-2.5 |
|
|||
Reference substance |
5 |
17.60 |
42.8 |
Reference substance |
15 |
8.84 |
71.3 |
Reference substance |
30 |
5.83 |
81.0 |
Test sample |
Nominal concentration of test substance (mg/l) |
Oxygen conc. At start (mg O2/l) |
Oxygen consumption (mg O2/l/h) |
% Inhibition respiration rate |
pH |
|
|
||||
Initial control |
0 |
6.4 |
68 |
- |
7.4 |
Final control |
0 |
7.3 |
63 |
- |
7.4 |
Dodecamethylcyclohexasiloxane (1) |
100 |
6.1 |
72 |
-10 |
7.4 |
Dodecamethylcyclohexasiloxane (2) |
100 |
7.1 |
68 |
-4 |
7.4 |
|
|
||||
3,5-dichlorophenol |
5 |
- |
- |
32 |
- |
12 |
- |
- |
73 |
- |
|
30 |
- |
- |
86 |
- |
Description of key information
Toxicity to microorganisms: 3 hour EC50 >1000 mg/l; NOEC >=1000 mg/l (OECD 209)
Key value for chemical safety assessment
Additional information
Under the conditions of the OECD TG 209 test, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was not toxic to waste water (activated sludge) bacteria up to and including a loading rate of 1000 mg/l (NOEC). The EC50 exceeded a loading rate of 1000 mg/l.
The registration substance has a purity of >70% Vi4-D4, with <20% 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane (Vi5-D5; CAS 17704-22-2; Impurity 1) and <10% 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane (Vi3-D3; CAS 3901-77-7; Impurity 2) present as impurities. After due consideration of the properties, the presence of these impurities is not expected to affect the overall hazard profile of the substance. Vi5-D5 and D5 are within the Reconsile Siloxane Category of substances within which, in general, the substances exhibit no evidence of significant toxicity to microorganisms. Table 7.1.7 presents microorganism toxicity data available for substances within the Siloxane Category. Vi3-D3 and D3 do not fall within the Category definition, however the substances are structurally similar, and a study with D3 concludes that no evidence of significant toxicity to STP organisms. It is therefore considered valid to read-across the results for D5 and D3. Additional information is given in a supporting report (Peter Fisk Associates, 2017) attached in Section 13 of the IUCLID 6 dossier.
Read-across studies are in place as supporting studies, to consider the properties of the impurities. Data for Vi5-D5 are read-across from decamethylcyclopentasiloxane D5 (CAS 541-02-6), data for Vi3-D3 are read-across from hexamethyltrisiloxane D3 (CAS 541-05-9). An ASRI 3 hour EC50 of >2000 mg/l was determined for D5. An ASRI EC50 >100 mg/l was determined for D3.
Table: Microorganism toxicity data available for substances within the Siloxane Category
CAS |
Name |
Result: E(I)C50(mg/l) |
Result: NOEC (or EC10/ EC20) (mg/l) |
Guideline Number |
Test method |
Duration (h) |
Reliability |
540-97-6 |
Dodecamethylcyclohexasiloxane |
>100 mg/l |
|
OECD 209 |
ASRI |
3 |
1 |
541-05-9 |
Hexamethylcyclotrisiloxane |
>100 mg/l |
>100 mg/l |
OECD 209 |
ASRI |
3 |
1 |
541-02-6 |
Decamethylcyclopentasiloxane |
>2000 mg/l |
|
C11 |
ASRI |
3 |
1 |
107-46-0 |
Hexamethyldisiloxane |
>>100 |
≥100 |
OECD 209 |
ASRI |
3 |
1 |
141-62-8 |
Decamethyltetrasiloxane |
>100 mg/l |
|
OECD 209 |
ASRI |
3 |
1 |
352230-22-9 |
Siloxanes and Silicones, di-Ph, Ph (trimethylsilyl)oxy |
>1000 mg/l |
≥1000 mg/l |
OECD 209 |
ASRI |
3 |
1 |
2627-95-4 |
1,1,3,3-tetramethyl-1,3-divinyldisiloxane |
>1000 mg/l |
≥1000 mg/l |
OECD 209 |
ASRI |
3 |
1 |
2554-06-5 |
2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane |
>1000 mg/l |
≥1000 mg/l |
OECD 209 |
ASRI |
3 |
1 |
N/A (EC 939-487-8) |
Phenyl silsesquioxanes |
>1000 |
≥1000 |
OECD 209 |
ASRI |
3 |
1 |
99363-37-8 |
dimethyl, methyl(3-aminopropyl) siloxane, trimethylsiloxy-terminated |
> water soluble fraction |
≥ water soluble fraction |
OECD 209 |
ASRI |
3 |
1 |
71750-79-3 |
dimethyl, (aminoethylaminopropyl)methyl siloxane, trimethylsiloxy-terminated |
> water soluble fraction |
≥ water soluble fraction |
OECD 209 |
ASRI |
3 |
1 |
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