Registration Dossier

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study conducted under GLP

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): PM 1265 (internal product designation) and Cyclobutanediol, 2,2,4,4-Tetramethyl
- Substance type: production sample
- Physical state: solid
- Lot/batch No.:TS060505
- Storage condition of test material: Ambient conditions

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples of the test solutions were collected at approximately 0 and 96 hours to measure concentrations of the test substance. Samples at test initiation were collected from the individual batches of test solution prepared for each treatment and control group prior to distribution into the test chambers. At exposure termination, samples were collected from the pooled replicates from each treatment and control group. All samples were collect in glass vials and processed immediately for analysis.

Test solutions

Vehicle:
no
Details on test solutions:
A primary stock solution was prepared by dissolving PM-1265 in freshwater algal medium at a nominal concentration of 120 mg/L. The stock was inverted at least 20 times to mix and appeared clear and colorless. The primary stock was proportionally diluted with freshwater algal medium to prepare the four additional test solutions at nominal concentrations of 7.5, 15, 30 and 60 mg/L. All test solutions appeared clear and colorless.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Original algal cultures of Pseudokirchneriella subcapitata (UTCC 37) were obtained from the University of Toronto, and had been maintained in culture medium at Wildlife International, Ltd., Easton, Maryland. Algal cells used in this test were obtained from Wildlife International, Ltd. cultures that had been actively growing in culture medium for at least two weeks prior to test initiation. The culture was last transferred to fresh medium four days prior to test initiation.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h

Test conditions

Test temperature:
24 ± 2°C
pH:
The pH of the test solutions at test initiation was 7.8 and at exposure termination ranged from 9.2 to 9.4. The pH tended to increase relative to increases in algal densities, which is typical for tests conducted with Pseudokirchneriella subcapitata.
Nominal and measured concentrations:
Nominal concentrations selected for use in this study were 7.5, 15, 30, 60 and 120 mg/L.
The mean measured test concentrations were 7.3, 13, 25, 51 and 108 mg/L
Details on test conditions:
Prior to test initiation, an inoculum of the algal cells was prepared in freshwater algal medium at a concentration of approximately 1.0 X 10e6 cells/mL. The concentration of algal cells was verified using a hemacytometer and microscope, and 1.0 mL of the inoculum was added to each test chamber to achieve a nominal concentration of approximately 10,000 cells/mL at test initiation. Test chambers were sterile, 250-mL Erlenmeyer flasks plugged with foam stoppers, and contained 100 mL of test or control medium. The algae were held under 24 hours per day of cool-white fluorescent lighting at an intensity of 4300± 10 % lux. Test medium samples were collected from each replicate of the treatment and control group for the determination of algal cell densities. Samples were collected at approximately 24-hour intervals during the 96-hour exposure. Cell counts were performed using an electronic particle counter.

Results and discussion

Effect concentrationsopen allclose all
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 108 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 108 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 108 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 108 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

A 96-Hour Toxicity Test with the Freshwater Alga (Pseudokirchneriella subcapitata) was conducted on PM 1265. The 72 and 96-hour EC50, EbC50 and ErC50 values, based on cell density, area under the growth curve and growth rate, respectively, for Pseudokirchneriella subcapitata exposed to PM-1265 were >108 mg/L, the highest measured concentration tested. The 72 and 96-hour NOAEC for each growth parameter was 108 mg/L.