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EC number: 612-185-0 | CAS number: 61636-08-6
- 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
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 18 October 1993 to 15 July 1994
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. No analytical determination of test substance concentration.
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 994
- Report date:
- 1994
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Deviations:
- yes
- Remarks:
- No analysis of test solutions.
- Qualifier:
- according to guideline
- Guideline:
- other: Toxic Substances Control Act Test Guidelines
- Deviations:
- not specified
- GLP compliance:
- yes
Test material
- Reference substance name:
- 2-ethoxy-6-hydroxy-3,4-dihydropyrimidin-4-one
- EC Number:
- 612-185-0
- Cas Number:
- 61636-08-6
- Molecular formula:
- C6H8 N2 O3
- IUPAC Name:
- 2-ethoxy-6-hydroxy-3,4-dihydropyrimidin-4-one
- Test material form:
- other: solid (unspecified)
- Details on test material:
- - Appearance: white to light tan solid
Constituent 1
Sampling and analysis
- Analytical monitoring:
- no
Test solutions
- Vehicle:
- no
Test organisms
- Test organisms (species):
- Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
- Details on test organisms:
- TEST ORGANISM
- Strain: 1648
CULTURE CONDITIONS
Stock cultures of this organism were maintained axenically by weekly transfer into sterile algal assay medium (AAM).
- Temperature: 25 ± 2 °C
- Light: 4300 ± 650 lux
- Photoperiod: Continuous
- Medium: as for the AAM Bottle Test (EPA-600/9-78-018)
- pH: 7.0 to 7.5
- Septic conditions: Axenic
- Culture vessel: 500 mL Erlenmeyer flask
- Habitat maintenance: Inoculation: 4 to 5 days; Culture chamber: Incubator; Amount of transfer: 20 000 cells/mL; Culture agitation: ~100 rpm; Acclimation: 4 weeks.
- Health criteria: Adequate growth: 1 x 10⁶ cells/mL in 5 days
Study design
- Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 5 d
Test conditions
- Test temperature:
- 24 ± 1 °C
- pH:
- 5.3 to 7.7 (without algae); 5.3 to 9.1 (with algae)
- Nominal and measured concentrations:
- Nominal treatment levels: 0 (medium control), 1.88, 3.75, 7.5, 15, 30 and 60 mg/L.
- Details on test conditions:
- TEST SYSTEM
- Test vessel: Sterilised 250 mL borosilicate Erlenmeyer flasks.
- Type: Closed with Shimadzu closures.
- Fill volume: 100 mL (algal test medium)
- Aeration: Flasks were continuously agitated at approximately 100 rpm.
- Initial cell density: Approximately 10 000 cells/mL. The stock culture was used to prepare an algal inoculum by diluting with test medium, such that a 1 mL aliquot of the inoculum would provide the appropriate cell density.
- No. of vessels per concentration (replicates): Three. A counting blank was included with each test concentration (contained growth medium and the appropriate amount of test material but no algae).
- No. of vessels per control (replicates): Six
GROWTH MEDIUM
- Standard medium used: yes (Algal Assay Medium)
The culture medium used for the definitive test was the same as that used to maintain the stock culture, with the exception that the medium used in the toxicity tests did not contain the chelant Na₂EDTA.2H₂O
- Preparation of the Algal Assay Medium:
Add one mL of each stock solution A, B1, B2, B3 and D, plus 10 mL of C to 900 mL of dilution water and make up to one litre with additional water. Each stock solution was filtered through a 0.45 µm membrane filter, then stored at 4 °C; the solutions were brought up to room temperature before using.
A: 12.75 g NaNO₃, 6.08 g MgCl₂.6H₂O and 2.20 g CaCl₂.2H₂O dissolved in 500 mL dilution water
B1: 7.35 g MgSO₄.7H₂O dissolved in 500 mL dilution water
B2: 7.5 g NaHCO₃ dissolved in 500 mL dilution water
B3: 0.522 g K₂PO₄ dissolved in 500 mL dilution water
C: 5 mL of number 1 (below) and 5 mL of number 3 (below) diluted to 500 mL with sterile dilution water.
1: 1.86 g H₃BO₃, 4.17 g MnCl₂.4H₂O, 0.0327 g ZnCl₂ and 0.0726 g NaMoO₄.2H₂O dissolved in 1000 mL dilution water
2: 2.86 g CoCl₂.6H₂O and 0.022 g CuCl₂.2H₂O dissolved in 1000 mL dilution water
3: 2.5 mL of number 2 was made up to 500 mL
D: 0.30 g Na₂EDTA.2H₂O and 0.16 g FeCl₃.6H₂O dissolved in 1000 mL dilution water
OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous illumination
- Light intensity and quality: 4300 ± 1100 lux
EFFECT PARAMETERS MEASURED
The algal densities of the inoculum and test cultures were determined by electron particle counting using a Coulter Multisizer. Total cell counts were determined at approximately 24, 48, 72, 96 and 120 hours. Cells were cumulatively counted from a lower threshold equivalent spherical diameter of approximately 2.7 µm to a higher threshold equivalent spherical diameter of approximately 8.6 µm. The background particle count (growth medium and test material) was concurrently subtracted from that of the sample dilution (growth medium, test material and algae) to obtain cell density. A blank correction for the isotonic saline solution used in preparing the dilutions was also compensated for in the calculations.
PHYSICAL ANALYSIS
Extra flasks without algae were added to the test for each nominal concentration to monitor pH at the initiation of the test and every day thereafter. At the end of the test a final pH was taken in a replicate test flask at each test concentration with algae. The temperature of a representative test solution was continuously monitored during the test. The light intensity was checked on a daily basis with readings taken corresponding to the positions of the test flasks in the incubator.
TEST CONCENTRATIONS
- Spacing factor for test concentrations: Test concentrations were set in a geometric series with a progression factor of 2.0.
- Range finding study: Yes
- Range finding test concentrations: 0.1, 1.0, 10, 100 and 1000 mg/L
- Results used to determine the conditions for the definitive study: Yes; the results indicated an inhibition of cell growth through 100 mg/L and essentially no effect at 10 mg/L in comparison to the controls. - Reference substance (positive control):
- no
Results and discussion
Effect concentrationsopen allclose all
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- 37 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Remarks on result:
- other: 95 % confidence interval 8.9 to 65.0 mg/L
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 30 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 120 h
- Dose descriptor:
- EC50
- Effect conc.:
- 37 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Remarks on result:
- other: 95 % confidence interval 15.4 to 58.0 mg/L
- Duration:
- 120 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 15 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Details on results:
- See Tables 1, 2 and 3.
- Reported statistics and error estimates:
- The results are expressed in terms of algal growth (total cell count/mL) and inhibition (percent). The EC50 values were determined for both endpoints. The EC10, EC50, and EC90 values for algal growth were numerically derived based on calculated regression equations for each 24 hour period. The no observed effect concentrations (NOECs) given for algal growth were calculated using analysis of variance and the Dunnett's test. The percent inhibition is a graphic interpretation of the data and the EC values were calculated by regression based on the comparison of the areas under the growth curves between the control group and each exposure concentration.
Any other information on results incl. tables
Table 1 Mean Values for Growth for Each Replicate Test Flask
Nominal Concentration (mg/L) |
Time (hours) |
||||
24 |
48 |
72 |
96 |
120 |
|
60 |
7460 7700 8707 |
5880 6493 7067 |
8827 7000 9053 |
8340 4453 6813 |
2087 807 1613 |
30 |
13093 14647 13513 |
36427 36827 38973 |
174400 134667 168733 |
459333 468667 592267 |
1153867 1082400 1688133 |
15 |
13820 16753 17340 |
41573 51653 44093 |
168333 194200 136933 |
690133 750000 632800 |
2204667 2221467 2072800 |
7.5 |
15000 14220 15607 |
46733 46720 62907 |
114867 128600 268000 |
384533 367733 931467 |
1935200 1508933 2801733 |
3.75 |
14120 16967 21227 |
41187 55493 54107 |
168067 236000 186733 |
592533 837733 737200 |
2219067 2474400 2354000 |
1.88 |
18760 19120 18980 |
58640 57467 58027 |
190533 217200 188067 |
849067 958400 805600 |
2422000 2863200 2282133 |
Control |
15280 17807 16673 15220 16947 18453 |
46560 47520 48880 46520 49760 55347 |
200867 176533 191400 154667 212267 224400 |
667733 669600 747600 598133 724000 770400 |
2134533 2120000 1912133 1761733 2053333 2007200 |
Table 2 Mean Five Day Test Results Showing the NOECs Using the One-tailed Dunnett’s Test
Nominal Concentration (mg/L) |
Statistics |
Time (hours) |
||||
24 |
48 |
72 |
96 |
120 |
||
60 |
Mean SD CV |
7956* 661.5 8.3 |
6480* 593.4 9.2 |
8293* 1125.8 13.6 |
6536* 1958.2 30.0 |
1502* 647.2 43.1 |
30 |
Mean SD CV |
13751* 803.5 5.8 |
37409* 1369.5 3.7 |
159267 21491.8 13.5 |
506756 74201.7 14.6 |
1308133* 331024.0 25.3 |
15 |
Mean SD CV |
15971 1885.9 11.8 |
45773 5245.8 11.5 |
166489 28677.9 17.2 |
690978 58604.6 8.5 |
2166311 81417.5 3.8 |
7.5 |
Mean SD CV |
14942 695.1 4.7 |
52120 9341.5 17.9 |
170489 84725.8 49.7 |
561244 320731.9 57.1 |
2081956 658776.0 31.6 |
3.75 |
Mean SD CV |
17438 3576.7 20.5 |
50262 7890.2 15.7 |
196933 35096.5 17.8 |
722489 123260.2 17.1 |
2349156 127735.6 5.4 |
1.88 |
Mean SD CV |
18953 181.5 1.0 |
58044 586.9 1.0 |
198600 16155.2 8.1 |
871022 78730.5 9.0 |
2522444 303276.2 12.0 |
Control |
Mean SD CV |
16730 1308.6 7.8 |
49098 3319.9 6.8 |
193356 25145.4 13.0 |
696244 63333.1 9.1 |
1998156 141327.0 7.1 |
SD = Standard deviation
CV = Coefficient of variation
*Comparisons significant by Dunnett’s one-tailed test at the 0.05 level (i.e. p≤0.05)
Table 3 Inhibition of Growth in Comparison to the Control at Each 24 Hour Interval
Nominal Concentration (mg/L) |
% Inhibition |
||||
24 h |
48 h |
72 h |
96 h |
120 h |
|
60 |
130.4 |
114.5 |
104.7 |
101.6 |
100.8 |
30 |
44.3 |
33.6 |
23.1 |
25.1 |
30.5 |
15 |
11.3 |
9.2 |
12.7 |
5.9 |
-2.5 |
7.5 |
26.6 |
1.1 |
7.4 |
15.6 |
6.0 |
3.75 |
-10.5 |
-4.9 |
-2.7 |
-3.2 |
-10.9 |
1.88 |
-33.0 |
-25.5 |
-10.0 |
-18.1 |
-23.7 |
Control |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
Applicant's summary and conclusion
- Validity criteria fulfilled:
- yes
- Conclusions:
- Under the conditions of this study, the 72 hour EC50 value and 95 % confidence interval for algal growth was 37 (8.9 to 65.0) mg/L. The 72 hour NOEC was 30 mg/L. Results are based on nominal concentrations.
- Executive summary:
The phytotoxicity of the test material to a freshwater green alga, Selenastrum capricornutum Printz, was investigated over a five day period in a study conducted under GLP conditions and in accordance with the standardised guideline OECD 201 and the Toxic Substances Control Act Test Guidelines.
During the study, algae, at an initial cell density of 10 000 cells/mL, were exposed to nominal concentrations of the test material of 0 (medium control) 1.88, 3.75, 7.5, 15, 30 and 60 mg/L under static conditions. The test flasks were incubated in an environmental growth chamber under continuous illumination with constant agitation. Growth (total cells/mL) and inhibition (percent) were determined.
Under the conditions of this study, the 72 hour EC50 value and 95 % confidence interval for algal growth was 37 (8.9 to 65.0) mg/L. The 72 hour NOEC was 30 mg/L. Results are based on nominal concentrations.
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