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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report date:
1995

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
sec. Alkane sulfonate
IUPAC Name:
sec. Alkane sulfonate
Constituent 2
Chemical structure
Reference substance name:
Sulfonic acids, C14-17-sec-alkane, sodium salts
EC Number:
307-055-2
EC Name:
Sulfonic acids, C14-17-sec-alkane, sodium salts
Cas Number:
97489-15-1
Molecular formula:
H3C-(CH2)m-CH-(SO3Na)-(CH2)n-CH3
IUPAC Name:
Sulfonic acids, C14-17-sec-alkane, sodium salts
Details on test material:
- Name of test material (as cited in study report): Alkansulfonate-Na
- Analytical purity: 61 % related on total sulfonate (56 % related to monosulfonate)
- Lot/batch No.: E 11 A 03673

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION:
- Method: The test substance was homogenized by intensive stirring. Then an adequate amount of the test substance was weighted into the test water for the preparation of the highest test concentration of nominal 100 mg/L. A delution series with the following nominal concentrations were tested: 1.0, 3.2, 10.0, 32.0 and 100 mg/L.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Green algae
- Strain: Scenedesmus subspicatus CHODAT, Strain No. 86.81 SAG
- Source: Sammlung von Algenkulturen, Pflanzenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen, D-37073 Göttingen. The algae were grown in the laboratories of RCC under standardized conditions according to the test guideline No. 201.
- Method of cultivation: The algae were cultivated and tested in synthetic test water, prepared according to the mentioned test guideline.

ACCLIMATION
- Culturing media and conditions: the same

Study design

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

Test conditions

Hardness:
0.24 mmol/L as CaCO3
Test temperature:
24.0-24.1 °C
pH:
7.9 (start of test) to 10.3 (end of test)
Nominal and measured concentrations:
nominal concentrations: 1.0, 3.2, 10.0, 32.0 and 100 mg/L.
measured concentrations: 0.9, 2.8, 8.7, 28.5, 90.0 mg/L (mean test substance concentration)
Details on test conditions:
TEST SYSTEM
- Test vessel: 50-mL Erlenmeyer flasks, covered with glass dishes
- Initial cell density: 10000
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6


GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to test guideline
Stock solution : macro nutrients
NH4Cl = 15 mg/L
MgCl2 × 6H2O = 12 mg/L
CaCl2 × 2H2O = 18 mg/L
MgSO4 × 7H2O = 15 mg/L
KH2PO4 = 1.6 mg/L
Trace elements:
H3BO3 = 185 µg/L
MnCl2 × 4H2O = 415 µg/L
ZnCl2 = 3 µg/L
CoCl2 × 6H2O = 1.5 µg/L
CuCl2 × 2H2O = 0.01 µg/L
Na2MoO4 × 2H2O = 7 µg/L

- Culture medium different from test medium: no
- Intervals of water quality measurement: pH at test start and test end.

OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Photoperiod: Continuously illuminated
- Light intensity and quality: 8258 Lux (7800-8550 Lux) with fluorescent tubes (universal white L 25, 36 W)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: with a electronic particle counter (AL CELLCOUNTER, Model 871)
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 61 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Remarks on result:
other: 61% a.i. in test mat.
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
58.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Remarks on result:
other: 61% a.i. in test mat.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
96.4 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
14.2 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Unusual cell shape: no
- Colour differences: no

Applicant's summary and conclusion

Executive summary:

The influence of the test substance on growth of the green algal species Scenedesmus subspicatus Chodat was investigated in a 72-hour static test according to the OECD guideline no. 201, adopted June 7, 1984. The test was performed in compliance with GLP.

The nominal test concentrations were 1.0, 3.2, 10.0, 32.0 and 100 mg/L and a control. Concentrations exceeding 100 mg/L (nominal) were not tested.

The analytically determined concentration of the test substance in the freshly prepared test media varied in the range from 96 to 99 of nominal in the test media. At the end of the test, the test substance concentrations had slightly decreased to 78–85 % of nominal. The reported biological results are related to the mean test substance concentrations.

The 72-hour LOEC (lowest concentration tested with toxic effects after the test period of 72 hours) was determined to be 28.5 mg/L. The 72-hour NOEC (highest concentration tested without toxic effects after the test period of 72 hours) was determined at the concentration of 8.7 mg/L.

The inhibition rates were calculated for both parameters the algal biomass b and the growth rate µ after 72 hours test duration. The test concentration corresponding to 90 % inhibition of the algal biomass b (EbC 90), respectively of the growth rate µ (EµC 90) could not be determined due to the low toxicity of the test substance.

Biomass b (determined as the area under the growth curves):

- EbC 10 = 14.2 mg/L

- EbC 50 > 100 mg/L

Growth rate µ:

- EµC 10 = 96.4 mg/L

- EµC 50 > 100 mg/L