Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From March 20, 1991 to September 26, 1991
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
KL2 due to RA
Justification for type of information:
Refer to the section 13 for details on the category justification.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: CHODAT (86.81 SAG)
- Source (laboratory, culture collection): Own culture started from a smaple obtained from the 'Institut für Wassr-, Boden- und Lufthygiene, Berlin, Germany'
- Age of inoculum (at test initiation): 3 d
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
22°C
pH:
8.2 - 8.6 at test start; 8.4 - 9.1 at test end
Nominal and measured concentrations:
- Nominal: 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 mg/L
Details on test conditions:
TEST SYSTEM
- Initial cells density: 20,000 cells/ml
- Control end cells density: 560,000 cells/ml
- No. of vessels per concentration (replicates): 5 - 8

GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Sterile conditions: yes
- Adjustment of pH: no
- Light intensity and quality: 8000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: photometric determination at 685 nm using a reference calibration curve.
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 18.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
ca. 1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 23.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
ca. 4.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Details on results:
- Exponential growth in the control (for algal test): yes

Table 1: Scenedesmus subspicatus cell density (10E+4 cell/ml) after exposure to the test substance

Concentration (mg/L)  0 h  24 h 48 h   72 h
 0  2  13  56
 0.5  2  4  15  60
 1.0  2  5  18  64
 2.0  4  16  61
 4.0  2  3  14  43
 8.0  2  3  21  21
 16.0  2  3  27  10
 32.0  2  4  7  13
Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, the nominal 24-72 h ErC50 was 18.6 mg/L. The nominal 72 h EbC50 was 23.4 mg/L and the NOEC was 2.0 mg/L.
Executive summary:

A study was conducted to determine the toxicity of the read across substance, C16-18 and C18-unsatd. DEA, to the green algae Scenedesmus subspicatus according to EU Method C.3, in compliance with GLP. Algae were exposed to the read across substance (directly dissolved in test medium) for 72 h at 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 mg/L under static conditions. Biomass and growth rate were determined. No analytical dose verification was conducted. During the incubation period, increased turbidity was noted at 8 mg/L and above. This was taken into account when calculating the toxicity data by subtracting the values for the parallel samples (same conditions, no algae) from the test sample (with algae). Under the study conditions, the nominal 24-72 h ErC50 was 18.6 mg/L. The nominal 72 h EbC50 was 23.4 mg/L and the NOEC was 2.0 mg/L (Scholz, 1991).

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
18.6 mg/L
EC10 or NOEC for freshwater algae:
2 mg/L

Additional information

A study was conducted to determine the toxicity of the read across substance, C16-18 and C18-unsatd. DEA, to the green algae Scenedesmus subspicatus according to EU Method C.3, in compliance with GLP. Algae were exposed to the read across substance (directly dissolved in test medium) for 72 h at 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 mg/L under static conditions. Biomass and growth rate were determined. No analytical dose verification was conducted. During the incubation period, increased turbidity was noted at 8 mg/L and above. This was taken into account when calculating the toxicity data by subtracting the values for the parallel samples (same conditions, no algae) from the test sample (with algae).Under the study conditions, the nominal 24 -72 h ErC50 was 18.6 mg/L. The nominal 72 h EbC50 was 23.4 mg/L and the NOEC was 2.0 mg/L (Scholz, 1991). 

Categories Display