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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:
31 December 1991 and 3 January 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to GLP and internationally accepted guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth 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): Dipentaerythritol

- Substance type: white powder
- Physical state: solid
- Analytical purity: 96.2%
- Impurities (identity and concentrations): mono-pentaerythritol (2.8%), tri-pentaerythritol (0.51%)

- Purity test date: Received 2 September 1991
- Lot/batch No.: 9404
- Expiration date of the lot/batch: 2 September 1993

- Stability under test conditions: Verified by chemical analysis.
- Storage condition of test material: in original container at room temperature in darkness
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 100 mg/L
- Sampling method: duplicate water samples were taken
- Sample storage conditions before analysis: samples stored at -20°C until analysis by Sponsor.

Test solutions

Vehicle:
no
Details on test solutions:
Direct dispersion in algal media with the aid of ultrasonic disruption

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Scenedesmus subspicatus
- Strain: CCAP 276/20
- Source (laboratory, culture collection): Culture Centre of Algae & Protozoa c/o Freshwater Biological Association, Cumbria, U.K.
- Age of inoculum (at test initiation):
- Method of cultivation:Sterile nutrient medium was inoculated from a master culture and incubated under continuous illumination (approx. 7000 lux) and stirring (orbital shaker) at 24 degree C to give an algal suspension in log phase growth characterised by an absorbance of 0.210 (at 665 nm).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
Not applicable

Test conditions

Hardness:
Not applicable
Test temperature:
24 ± 1 °C
pH:
7.2 - 8.4
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal: 100 mg/L; Mean measured 114 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type : 250 ml conical flask
- Material, size, headspace, fill volume: glass vessels containing 100 ml test solution
- Aeration: none. gaseous exchange and suspension of algal cells maintained by orbital shaker.
- Initial cells density: 0.85 x 10^4 cells/ml
- Control cells density after 72 hours exposure: 1.5 x 10^6 cells/ml

- No. of vessels per concentration (replicates): six
- No. of vessels per control (replicates):three


GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: not specified
- Photoperiod:continuous
- Light intensity and quality:7000 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : 0, 24, 48 and 72 hours
- Determination of cell concentrations: absorbance measured at 665 nm. Cell densities of the control cultures at initiation and at termination were determined by direct counting with the aid of a haemacytomter.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 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): no abnormalities detected
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
Statistics used were detailed in the guudeline.

Any other information on results incl. tables

The area under the growth curve after 72 hours was as follows:

Control - 7.116

100 mg/L - 7.448

The growth rate, 48 - 72 hours was as follows:

Control - 0.043

100 mg/L - 0.042

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The freshwater algae Scenedesmus subspicatus was exposed to a nominal exposure concentration of 100 mg/L dipentaerythritol for 72 hours under static conditions. The mean measured concentration of the 100 mg/L test treatment was 114 mg/L which indicated that the test medium had been adequately prepared. As the measured concentration was within +/- 20% of the nominal concentration the results of the study are based on the nominal exposure concentration. No effects were seen on either growth rate or biomass, therefore the 72 hour EbC50 and 72 hour ErC50 were both >100 mg/L, the corresponding no-observed effect concentrations (NOEC) were both observed to be 100 mg/L.
Executive summary:

The freshwater algae Scenedesmus subspicatus was exposed to a nominal exposure concentration of 100 mg/L dipentaerythritol for 72 hours under static conditions. The mean measured concentration of the 100 mg/L test treatment was 114 mg/L which indicated that the test medium had been adequately prepared. As the measured concentration was within +/- 20% of the nominal concentration the results of the study are based on the nominal exposure concentration. No effects were seen on either growth rate or biomass, therefore the 72 hour EbC50 and 72 hour ErC50 were both >100 mg/L, the corresponding no-observed effect concentrations (NOEC) were both observed to be 100 mg/L.