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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Qualifier:
according to
Guideline:
other: DIN 38412-33
Version / remarks:
1991
GLP compliance:
not specified
Remarks:
Test before implementation of GLP
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
25 °C
pH:
8.2 ± 0.2
Nominal and measured concentrations:
5 concentrations nominal
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer flasks stoppered with cotton plugs
- Material, size, headspace, fill volume: 300 mL with 80 mL test solution and 10 mL algal grow medium
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- Initial cells density: 10E4
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
Composition of mineral medium per liter:
NH4Cl, 15 mg; MgC12 * 6H2O, 12 mg; CaC12 - 2H2O, 18 mg; MgSO4 - 7H2O, 15 mg; KH2PO4, 1.6 mg; NaHCO3, 150 mg;
FeCh . 6H2O, 80 pg; Na2EDTA - 2H2O, 100 pg; H3BO3, 185 pg; MnC12 * 4H2O, 415 pg; ZnC12, 3 pg; CoCI2 * 6H2O, 1.5 pg;
CuC12. 2H2O, 0.01 pg; Na2MoO4 . 2H2O, 7 pg.

OTHER TEST CONDITIONS
- Adjustment of pH: 8.2 ± 0.2
- Light intensity and quality: uniform illumination with a photon light intensity of about 0.72 E20 photons/m² * s (120 µE/m2 * s)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorimeter


Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
130 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
EC50 was calculated by probit analysis and line of the best fit.
Validity criteria fulfilled:
yes
Conclusions:
EC50 of Guanidine Thiocyanate was calculated to be 130 mg/l.
Executive summary:

In a 72 hour acute toxicity study, the cultures of Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) were exposed to Guanidine Thiocyanate under static conditions. 

EC50values based on measurement of in vivo chlorophyll fluorescence was 130 mg/l (nominal). 

Results Synopsis

Test Organism: Desmodesmus subspicatus (previous name: Scenedesmus subspicatus

Test Type: Static

72 h EC50: 130 mg/l (nominal)

Description of key information

In a 72 hour acute toxicity study, the cultures of Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) were exposed to Guanidine Thiocyanate under static conditions. 

EC50values based on measurement of in vivo chlorophyll fluorescence was 130 mg/l (nominal). 

Key value for chemical safety assessment

EC50 for freshwater algae:
130 mg/L

Additional information