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EC number: 692-762-1 | CAS number: 166524-65-8
- 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:
- 25 October 1993 to 15 July 1994
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Study conducted 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. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.
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:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: Toxic Substances Control Act Test Guidelines
- Deviations:
- no
- GLP compliance:
- yes
Test material
- Reference substance name:
- 2-ethoxy-4,6-difluoropyrimidine
- EC Number:
- 692-762-1
- Cas Number:
- 166524-65-8
- Molecular formula:
- C6H6F2N2O
- IUPAC Name:
- 2-ethoxy-4,6-difluoropyrimidine
- Test material form:
- other: liquid (unspecified)
- Details on test material:
- - Name of test material (as cited in study report): 2-ethoxy-4,6-difluoropyrimidine
- Appearance: clear liquid
Constituent 1
Sampling and analysis
- Analytical monitoring:
- no
Test solutions
- Vehicle:
- no
- Details on test solutions:
- The test material was used as received; it was added directly to the test medium.
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:
- 24.2 - 24.6 °C
- pH:
- 7.3 - 7.6 (without algae); 7.2 - 8.9 (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. the medium was stored in the dark at approximately 4 °C.
- 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 cell 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.:
- 18 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Remarks on result:
- other: 4.3 - 71.5 mg/L (95 % CL)
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 15 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 120 h
- Dose descriptor:
- EC50
- Effect conc.:
- 32 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Remarks on result:
- other: 13.9 - 50.9 mg/L (95 % CL)
- 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 Conc. (mg/L) |
Day 1 |
Day 2 |
Day 3 |
Day 4 |
Day 5 |
60 |
8800 |
12720 |
15333 |
43853 |
109600 |
9140 |
9827 |
9893 |
32440 |
88907 |
|
16147 |
11147 |
7933 |
42493 |
125773 |
|
30 |
8953 |
23000 |
83707 |
178733 |
690000 |
9773 |
13280 |
32493 |
107200 |
425333 |
|
20993 |
17107 |
33867 |
133200 |
487933 |
|
15 |
14860 |
32813 |
66600 |
234933 |
940933 |
10440 |
47667 |
98533 |
299600 |
1175600 |
|
9960 |
35600 |
113267 |
336667 |
1100800 |
|
7.5 |
10107 |
44760 |
101733 |
418800 |
1267200 |
10053 |
34453 |
86600 |
352667 |
1221733 |
|
11447 |
33347 |
125933 |
461200 |
1331733 |
|
3.75 |
32480 |
31227 |
143067 |
518800 |
1545867 |
11787 |
23067 |
118467 |
452267 |
1369733 |
|
11793 |
44840 |
126267 |
420933 |
1249867 |
|
1.8 |
12500 |
43053 |
176200 |
533467 |
1625200 |
11453 |
40640 |
94400 |
370533 |
1036933 |
|
11633 |
38013 |
157533 |
456667 |
1376533 |
|
0 (control) |
12600 |
43240 |
164067 |
606800 |
1608933 |
11513 |
32107 |
140533 |
487200 |
1265467 |
|
11973 |
29933 |
127200 |
432200 |
1190933 |
|
13547 |
40013 |
141800 |
492133 |
1449867 |
|
12907 |
32693 |
87667 |
264000 |
878267 |
|
20433 |
39107 |
173533 |
541733 |
1457867 |
Table 2: Mean Five Day Test Results Showing the NOECs Using the One-tailed Dunnett’s Test
Nominal Concentration (mg/L) |
Statistics |
Day 1 |
Day 2 |
Day 3 |
Day 4 |
Day 5 |
60 |
Mean SD CV |
11362 4146.9 36.5 |
11231* 1448.5 12.9 |
11053* 3834.0 34.7 |
39596* 6234.1 15.7 |
108093* 18479.5 17.1 |
30 |
Mean SD CV |
13240 6727.1 50.8 |
17796* 4896.5 27.5 |
50022* 29179.7 58.3 |
139711* 36208.4 25.9 |
534422* 138322.2 25.9 |
15 |
Mean SD CV |
11753 2701.1 23.0 |
38693 7895.1 20.4 |
92800 23855.8 25.7 |
290400* 51486.9 17.7 |
1072444 119875.5 11.2 |
7.5 |
Mean SD CV |
10536 789.5 7.5 |
37520 6294.4 16.8 |
104756 19840.1 18.9 |
410889 54697.4 13.3 |
1273556 55274.7 4.3 |
3.75 |
Mean SD CV |
18687 11945.4 63.9 |
33044 10999.9 33.3 |
129267 12571.4 9.7 |
464000 49977.2 10.8 |
1388489 148888.6 10.7 |
1.88 |
Mean SD CV |
11862 559.6 4.7 |
40569 2520.8 6.2 |
142711 42867.0 30.0 |
453556 81511.2 18.0 |
1346222 295302.4 21.9 |
Control |
Mean SD CV |
13829 3312.5 24.0 |
36182 5308.0 14.7 |
139133 30349.1 21.8 |
470678 117053.6 24.9 |
1308556 258197.4 19.7 |
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: Percentage Inhibition of Growth in Comparison to the Control at Each 24 Hour Interval
Nominal Conc. (mg/L) |
Day 1 |
Day 2 |
Day 3 |
Day 4 |
Day 5 |
60 |
64.4 |
88.3 |
96.7 |
95.3 |
93.5 |
30 |
15.4 |
57.8 |
67.2 |
70.2 |
65.1 |
15 |
54.2 |
4.8 |
24.0 |
34.9 |
27.1 |
7.5 |
86.0 |
15.5 |
20.2 |
17.0 |
9.0 |
3.75 |
-126.9 |
-19.4 |
3.4 |
2.9 |
-2.0 |
1.88 |
51.4 |
-1.3 |
-4.5 |
0.7 |
-0.6 |
0 (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 and 120 hour EC50 values (and their 95 % confidence intervals) for algal growth were 18 (4.3 - 71.5) and 32 (13.9 - 50.9) mg/L, respectively, and for percent inhibition were 18 (5.3 - 62.6) and 20 (5.0 - 79.3) mg/L, respectively. The 72 and 120 hour NOECs for algal growth were both 15 mg/L.
- 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 and 120 hour EC50 values (and their 95 % confidence intervals) for algal growth were 18 (4.3 - 71.5) and 32 (13.9 - 50.9) mg/L, respectively, and for percent inhibition were 18 (5.3 - 62.6) and 20 (5.0 - 79.3) mg/L, respectively. The 72 and 120 hour NOECs for algal growth were both 15 mg/L.
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