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EC number: 265-929-8 | CAS number: 65799-47-5
- 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 aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2003-11-18 to 2003-11-21
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- The study was conducted according to the appropriate OECD guideline, in accordance with GLP and analytical monitoring was carried out. However in all the test concentrations bright green dispersions were observed by the end of the test period and in the highest 3 concentrations clumps of algal cells were noted. At the nominal concentrations of 32 mg/l and below no algal clumps were recorded. Therefore a more reliable result is based on these concentrations, leading to an EC50 value at concentrations at which no clumps were observed.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Deviations:
- no
- GLP compliance:
- yes
- Analytical monitoring:
- yes
- Details on sampling:
- - Concentrations: Water samples were taken from the control (replicates RI - R3 pooled) and each test group (replicates RI - R3 pooled) at 0 and 72 hours for quantitative analysis.
- Sampling method: direct from vessels
- Sample storage conditions before analysis: Duplicate samples were taken at 0 hours and stored (approximately -20°C) for further analysis if necessary. Sample volumes required for chemical analysis precluded the storage of duplicate samples at 72 hours. - Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Amounts of test material (640 and 200 mg) were each separately dissolved in culture medium and the volumes adjusted to 2 litres to give 320 and 100 mg/lL stock solutions respectively. A series of dilutions was made from these stock solutions to give further stock solutions of 32, 10, 3.2, 1.0 and 0.32 mg/L. An aliquot (1 litre) of each of the stock solutions was separately inoculated with algal suspension (5.0 ml) to give the required test concentrations of 0.32, 1.0,3.2, 10,32, 100 and 320 mg/L.
- Controls: culture medium - Test organisms (species):
- Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
- Details on test organisms:
- TEST ORGANISM
- Strain: CCAP 276/20
- Source (laboratory, culture collection): from the Culture Collection of Algae and Protozoa (CCAP), Institute of Freshwater Ecology, The Ferry House, Far Sawrey, Ambleside, Cumbria. Cultures were maintained in the laboratory by the periodic replenishment of culture medium.
- Age of inoculum (at test initiation):
- Method of cultivation:
ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed: - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 72 h
- Test temperature:
- 24 ± 1°C
- pH:
- range: 7.3 to 8.1 in the controls
- Nominal and measured concentrations:
- Nominal concentrations: 0.32, 1.0, 3.2, 10, 32, 100 and 320 mg/l
- Details on test conditions:
- TEST SYSTEM
- Test vessel: flasks
- Material, size, headspace, fill volume: 250 ml conical flasks, filled with 100 ml test medium
- Initial cells density: 1 x 10^4 cells/ml
- Control end cells density: 5.89 x 10^5 cells per ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
GROWTH MEDIUM
- Standard medium used: yes
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap water
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH was measured at 0 h and at 72 h. The temperature of the incubator was recorded daily.
OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: none reported
- Photoperiod: continuous illumination
- Light intensity and quality: approx 7000 lux
EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: electronic particle counter, every 24 h
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3
- Range finding study: two range finding studies were conducted, the first results the results obtained showed a flat response in terms of inhibition of growth rate. Both tests tested the same concentrations.
- Test concentrations: 0.10, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: no statistically significant decrease in gell cell growth was observed at 0.1 and 1.0 mg/L, however growth was observed to be reduced at 10 and 100 mg/L. - Reference substance (positive control):
- no
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 17 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- 1.8 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 32 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 3.2 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Details on results:
- - Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): see Any other information on material and methods section
- Flocculation: see Any other information on material and methods section
- Aggregation of algal cells: After 72 hours there were no abnormalities detected in the control or test cultures at 0.32, 1.0, 3.2 and 10 mg/l, however cell clumping was observed in the test cultures at 32, 100 and 320 mg/L.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: see Any other information on material and methods section
- Effect concentrations exceeding solubility of substance in test medium: the test substance hydrolyses rapidly. - Reported statistics and error estimates:
- Dunnett's multiple comparison procedure (1995), using SAS computer software package.
It was not possible to calculate 95% confidence limits for the ECM values as the data generated did not fit the models available for the calculation of confidence limits. - Validity criteria fulfilled:
- yes
- Conclusions:
- A 72 h ErC50 nominal value of 280 mg/L, equivalent to 2.7 to 6.8 mg/l parent substance (geom. mean), and a NOEC nominal value of 1.0 mg/L (geometric mean not available) have been determined for the effects of the test substance on the growth rate of the freshwater algae Scenedesmus subspicatus. In all the test concentrations bright green dispersions were observed by the end of the test period and in the highest 3 concentrations clumps of algal cells were noted. It cannot be excluded that the observed effects are related to undispersed test material, attributable by the reviewer to the formation of less soluble tetramers of the hydrolysis product of the registered substance. Therefore the results of the study should be treated with caution. At the nominal concentrations of 32 mg/l and below no algal clumps were recorded. Therefore a more reliable EC50 should be based on these concentrations. A 72 h ErC50 value of >32 mg/l nominal, equivalent to >17 mg/l measured initial (geometric mean not possible), and a NOEC of 3.2 mg/l nominal, 1.8 mg/l, measured initial, have thus been estimated by the current reviewer, where 19% and 7% inhibition were recorded at 17 and 1.8 mg/l respectively.
Reference
Analytical monitoring:
Analysis of the test solutions at 0 hours showed measured test concentrations of the parent test material to ranged from 32% to 58% of nominal. The variable results obtained were considered to be due to the rapid hydrolysis of the parent test material. Analysis of the test solutions at 72 hours showed a marked decline in measured test concentrations of parent test material with concentrations ranging from less than the limit of quantification (LOQ) of the analytical method employed to 0.1% of nominal. This decline was due to the instability of the test material in culture medium and was in-line with the preliminary stability analyses conducted which indicated that the test material was unstable.
The hydrolysis product of the substance is subject to further hydrolysis (epoxide ring opening). It is the opinion of the reviewer that this explains the difference between measured and expected hydrolysis product concentration.
Table 1. Analytical results
Hydrolysis product | Parent test material | Total Peak Area | Geometric mean hydrolysis product | Geometric mean parent substance | |||||
Sample | Nominal concentration (mg/l) | Concentration found (mg/l) | Expressed as % of nominal | Concentration found (mg/l) | Expressed as % nominal | Concentration found (mg/l) | Expressed as % nominal | 0 -72 h (mg/l) | 0 -72 h (mg/l) |
0 hours | Control | <LOQ | - | <LOQ | - | <LOQ | - | - | - |
0.32 | <LOQ | - | 0.104 | 32 | 0.104 | 32 | |||
1.0 | 0.006 | 0.6 | 0.599 | 56 | 0.565 | 57 | |||
3.2 | 0.103 | 3 | 1.82 | 57 | 1.92 | 60 | |||
10 | 0.541 | 5 | 5.67 | 57 | 6.21 | 62 | |||
32 | 2.30 | 7 | 17.1 | 54 | 19.4 | 61 | |||
100 | 6.61 | 7 | 57.9 | 58 | 64.5 | 64 | |||
320 | 24.8 | 8 | 165 | 52 | 190 | 59 | |||
72 hours | Control | <LOQ | - | <LOQ | - | <LOQ | - | - | - |
0.32 | <LOQ | - | <LOQ | - | <LOQ | - | - | - | |
1.0 | <LOQ | - | <LOQ | - | <LOQ | - | - | - | |
3.2 | - | - | <LOQ | - | <LOQ | - | - | - | |
10 | <LOQ | - | <LOQ | - | <LOQ | - | - | - | |
32 | <LOQ | - | <LOQ | - | <LOQ | - | - | - | |
100 | <LOQ | - | 0.125 | 0.1 | 0.125 | 0.1 | - | 2.7 | |
320 | <LOQ | - | 0.277 | 0.1 | 0.277 | 0.1 | - | 6.8 |
Table 2. Cell densities and percentage growth inhibition.
Nominal concentration (mg/L) | Area under the curve at 72 h | % inhibition | Growth rate (0 -72 h) | % inhibition |
Control | 1.63 x10^7 | - | 0.057 | - |
0.32 | 1.66 x10^7 | [2] | 0.058 | [2] |
1.0 | 1.66 x10^7 | [2] | 0.058 | [2] |
3.2 | 1.25 x10^7 | 24 | 0.053 | 7 |
10 | 8.22 x10^6 | 50 | 0.043 | 25 |
32 | 8.78 x 10^6 | 46 | 0.046 | 19 |
100 | 7.04 x10^6 | 57 | 0.038 | 33 |
320 | 3.07 x10^6 | 81 | 0.026 | 54 |
Description of key information
EC50 (72 h): >25 mg/l; NOEC: 2.5 mg/l (expressed in terms of [3-(2,3-epoxypropoxy)propyl]methylsilanediol).
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 25 mg/L
- EC10 or NOEC for freshwater algae:
- 2.5 mg/L
Additional information
A 72 h ErC50 nominal value of 280 mg/L, equivalent to 2.7 to 6.8 mg/l parent substance (geometric mean), and a NOEC nominal value of 1.0 mg/l (geometric mean not available) have been determined for the effects of [3-(2,3-epoxypropoxy)propyl]diethoxy(methyl)silane (CAS 2897-60-1) on the growth rate of the freshwater algae Scenedesmus subspicatus. In all the test concentrations bright green dispersions were observed by the end of the test period and in the highest 3 concentrations clumps of algal cells were noted. It cannot be excluded that the observed effects are related to undispersed test material. Therefore the results of the study should be treated with caution, however the results are taken forward for use in the chemical safety assessment as they represent a conservative worst case. At the nominal concentrations of 32 mg/l and below no algal clumps were recorded. Therefore a more reliable EC50 should be based on these concentrations. A 72 h ErC50 value of >32 mg/l nominal, equivalent to >17 mg/l measured initial (geometric mean not possible), and a NOEC of 3.2 mg/l nominal, 1.8 mg/l, measured initial, have thus been estimated by the current reviewer; where 19% and 7% inhibition were recorded at 17 and 1.8 mg/l respectively.
Epoxides are known to have the potential for enhanced toxicity due to a specific mode of action to higher organisms (e.g. by Lipnick, 1991); therefore even though the available experimental data provide an assessment limited to a relatively low concentration, the assessment is driven by the data on invertebrates and the uncertainties in interpretation of this test result are not considered critical to the data set.
Due to the rapid hydrolysis rate of the test substance it is likely that the test organisms were predominantly exposed to the hydrolysis products of the test substance.
The results may be expressed in terms of concentration of the hydrolysis product, (2,3-epoxypropoxy)propyl]methylsilanediol, by applying a molecular weight correction: (MW of silanol = 192.28 / MW of parent = 248.40) * >32 mg/l = >25 mg/l. The NOEC value is converted using the same method.
[3-(2,3 -Epoxypropoxy)propyl]methylsilanediol is susceptible to further hydrolysis reactions and the ultimate hydrolysis product 3-{3-[dihydroxy(methyl)silyl]propoxy}propane-1,2-diol is considered unlikely to exhibit significant ecotoxic effects based on QSAR estimated E(L)C50s >>100 mg/l (ECOSAR). The rate of reaction under environmental conditions is uncertain.
Refer to IUCLID Section 6 endpoint summary for further discussion of the approach to chemical safety assessment and justification for read across.
Reference
Lipnick RL. 1991. Outliers: their origin and use in the classification of molecular mechanisms of toxicity. Sci. Total. Environ. 109-110:131153.
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