Guanidinium thiocyanate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

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

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