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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 October 1992 to 16 November 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
1984
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Composite samples (about 150 mL per test concentration and control) were drawn by mixing identical volumes of the test solutions taken from the approximate centre of the test vessels.
- They were taken immediately before exposure and after 48 hours exposure and kept at -18 to -22 °C until analysis.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- 100.3 mg test material was mixed and made up to 1000 mL with water.
- Calculated amounts of the stock solution to produce the desired test concentrations were given into the water and were homogeneously distributed. The algae were then transferredTEST SYSTEM
- Test vessel: 100 mL Erlenmeyer flasks, stoppered with aluminium caps, on Lab-shaker
- Material, size, headspace, fill volume: 50 mL
- Initial cells density: 9400 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Composition according to the guideline
- Intervals of water quality measurement: Temperature was continuously measured and maintained at 23 ± 1°C. pH was measured at 0 and 72 h exposure.


OTHER TEST CONDITIONS
- Photoperiod: Continuous illumination
- Light intensity and quality: cold white fluorescent light, 109 µE/m^2 sec (approx. 8000 lux)


EFFECT PARAMETERS MEASURED:
- Cell densities were measured at 24, 48 and 72 hours exposure on a “TOA” cell counter.
into the flasks. The test material was homogeneously distributed in the test vessels at all test times and test concentrations.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Green algae
- Source (laboratory, culture collection): Collection of algae cultures, Pflanzenphysiologisches Institut, University, Nikolausberger Weg 18, 0-3400 Göttingen, Germany
- Method of cultivation: cultured according to OECD 201

ACCLIMATION
- Acclimation period: 3 days under test conditions
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
23 ± 1 °C
pH:
6.6 - 8.4
Nominal and measured concentrations:
Nominal: 1.23, 3.7, 11, 33 and 100 mg/L
Measured (0 hours): 1.2, 3.6, 10.4, 31.5 and 96.5 mg/L
Measured (72 hours): 1.3, 3.3, 10.1, 30.9 and 94.2 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL Erlenmeyer flasks, stoppered with aluminium caps, on Lab-shaker
- Material, size, headspace, fill volume: 50 mL
- Initial cells density: 9400 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Composition according to the guideline
- Intervals of water quality measurement: Temperature was continuously measured and maintained at 23 ± 1°C. pH was measured at 0 and 72 h exposure.


OTHER TEST CONDITIONS
- Photoperiod: Continuous illumination
- Light intensity and quality: cold white fluorescent light, 109 µE/m^2 sec (approx. 8000 lux)


EFFECT PARAMETERS MEASURED:
- Cell densities were measured at 24, 48 and 72 hours exposure on a “TOA” cell counter.
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Reported statistics and error estimates:
The EbC-50 values were calculated according to the maximum likelihood method, probit model (Mc Cullagh, P., Nelder, J.A., 1983: Generalised linear models, Chapman & Hall, London)

Table 1: Summary of Results

Nominal Concentration (mg/L)

Mean Cell Density (cells/mL*10000)

Inhibition of growth(%)

24 hours

48 hours

72 hours

0-72 h

Blank

3.3

17.3

85.7

0.0

1.23

3.3

16.9

123.0

0.0

3.7

3.3

17.6

129.0

0.0

11

3.0

16.9

112.2

0.0

33

3.7

17.8

114.8

0.0

100

3.8

12.0

74.2

17.3

 

Validity criteria fulfilled:
not specified
Conclusions:
Under the conditions of this study the EbC50 (0-72 h) was >100 mg/L and the NOEbC was 100 mg/L.
Executive summary:

The short-term toxicity of the test material to aquatic algae was investigated in accordance with the standardised guideline OECD 201, under GLP conditions.

Green algae (Scenedesmus subspicatus) was exposed to the test material at nominal concentrations of 1.23, 3.7, 11, 33 and 100 mg/L for 72 hours. Each test concentration was tested in triplicate and 6 control flasks were also used. Cell densities were measured at 24, 48 and 72 hours using a cell counter.

The test material concentrations were analytically determined using UV-Vis and were shown to be between 89 - 106 % of the nominal values.

Under the conditions of this study the EbC50 (0-72 h) was >100 mg/L and the NOEbC was 100 mg/L.

Description of key information

Under the conditions of this study the EbC50 (0-72 h) was >100 mg/L and the NOEbC was 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The short-term toxicity of the test material to aquatic algae was investigated in accordance with the standardised guideline OECD 201, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Green algae (Scenedesmus subspicatus) was exposed to the test material at nominal concentrations of 1.23, 3.7, 11, 33 and 100 mg/L for 72 hours. Each test concentration was tested in triplicate and 6 control flasks were also used. Cell densities were measured at 24, 48 and 72 hours using a cell counter.

The test material concentrations were analytically determined using UV-Vis and were shown to be between 89 - 106 % of the nominal values.

Under the conditions of this study the EbC50 (0-72 h) was >100 mg/L and the NOEbC was 100 mg/L.