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Ecotoxicological information

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:
2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study performed according to OECD guideline
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Alkyl (C12-C14) glycidyl ether
Label: Epoxide 8
51% C12 Glycidyl ether
21% C14 Glycidyl ether
5% C16 Glycidyl ether
13% N +1's
4% alpha addition Products
94% total active (Label claim)

- Physical state: Clear colorless
- Storage condition of test material: ambient

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples of each test group were saved for dose verification analysis. HPLC was used to analyze these
samples. Results from these analyses indicated that very little detectable material dissolved into the
solution, likely due to the test material’s low solubility. The method indicated little difference in actual
concentration among all of the test groups. Overall, the test demonstrated a good dose-response;
therefore, the nominal test concentrations were used in data analysis.

Test solutions

Vehicle:
no
Details on test solutions:
Algal stock culture medium (Woods Hole) with EDTA up to 0.300 mg/L

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM

- Source (laboratory, culture collection): Stillmeadow, Inc. cultures
- Age of inoculum (at test initiation): Mass culture initiated 3 - 7 +/- 1 days prior to dosing
- Density: initial cell density was 10000 cells/mL
- Method of cultivation: six days prior to testing, 900 mL of autoclaved algal stock culture medium was inoculated. This mass culture was placed in a 21 - 25 +/- 2°C environemental chamber and maintained on continuous aeration.


Study design

Test type:
other: constant agitation (shaker table 100 cycles/minute)
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
none

Test conditions

Test temperature:
21 - 25 +/- 2°C
pH:
7.0 to 9.6 at termination
Dissolved oxygen:
Test containers received conctant aeration
Nominal and measured concentrations:
nominal concentrations: 500 mg/L, 1000 mg/L, 2000 mg/L, 4000 mg/L and 8000 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 250-mL sterile Erlenmeyer flasks with stoppers and aeration tubing
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 250 mL sterile Erlenmeyer flasks
- Aeration: constant
- Initial cells density: 10000 cells/mL
- Control end cells density: increased by a factor greather than 16 for the vehicle control
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 6


GROWTH MEDIUM
- Standard medium used: yes, Algal stock culture medium (Woods hole) with EDTA up to 0.300 mg/L



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Freshwater



OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: No
- Photoperiod: Continuous lighting



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: daily using a hemacytometer
- Chlorophyll measurement: No



TEST CONCENTRATIONS
- Spacing factor for test concentrations: factor 2

- Range finding study
- Test concentrations: 0.1 mg/L, 1.0 mg/L, 10 mg/L, 100 mg/L, 500 mg/L and 1000 mg/L
- Results used to determine the conditions for the definitive study: No detailed results given for the dose range findings but 500 mg/L was selected as the lowest dose level to be used in the main study.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
IC50
Effect conc.:
843.75 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks on result:
other: 95% CL of 582.44 - 1097.71 mg/L
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Details on results:
The mean cells counts of the test concentration containers were compared to the control counts. The test concentration that resulted in 50% inhibition (IC50) was determined to be 843.75 mg/L with 95% CL of 582.44 - 1097.71 mg/L. The NOEC was determined to be 500 mg/L.
HPLC was used to analyse the dose levels. Results indicated that very little detectable material dissolved into the solution, likely due to the test material's low solubility. The method indicated little difference in actual concentration among all test group. The nominal test concentrations were used in data analysis. Since the control density increased by a factor greater than 16 and the coefficient of correlation was < 20%, the test is considered to be valid.
Results with reference substance (positive control):
All three replicates showed 0 cells/ml at 24, 48, and 72 hours

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
IC50 = 843.75 mg/L
NOEC = 500 mg/L
Since the water solubility of the substance was determined to be 0.483 mg/L, the IC50 is > solubility concentration.
Executive summary:

This study was conducted to determine the toxic effects of Alkyl (C12-C14) glycidyl ether; CAS RN

68609-97-2 (hereafter referred to as Alkyl glycidyl ether) on the growth of the freshwater algae

Selenastrum capricornutum in a 72-hour test.

The test substance concentrations of 500, 1000, 2000, 4000, and 8000 mg/L (based on a preliminary

range-finding test) were administered to the test system, Selenastrum capricornutum, in sterile medium.

For each test concentration, three test containers containing the freshwater algae (initial cell density of

10,000 cells/mL) were treated with the appropriate concentration of the test substance. A control group

consisted of six test containers containing sterile medium and the test culture only. A positive control

group consisted of three replicates treated with 10 mg/L potassium dichromate. The cell density in each

test and control container was measured daily using a hemacytometer. The pH of each test and control

container was determined at test termination. The test was terminated after 72 ± 2 hours of exposure.

The mean cell counts of the test concentration containers were compared to the control counts. The test

concentration that resulted in 50% inhibition (IC50) was determined to be 843.75 mg/L with 95%

confidence limits of 582.44-1097.71 mg/L. The NOEC (No Observed Effect Concentration) was

determined to be 500 mg/L.

HPLC was used to analyse the dose levels. Results indicated that very little detectable material dissolved into the solution, likely due to the test material's low solubility. The method indicated little difference in actual concentration among all test group. The nominal test concentrations were used in data analysis. Since the control density increased by a factor greater than 16 and the coefficient of correlation was < 20%, the test is considered to be valid.