6-(cyclohexylamino)-3-methyl-3H-dibenz[f,ij]isoquinoline-2,7-dione

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

Study period:

2020-06 till 2020-11-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Sampling schedule:

Control : at 72 hours

Test concentration/s : 100 mg/L at 0, 24, 48 and 72 hours

Vehicle:

yes

Details on test solutions:

To bring the test item into solution Acetone was used as solvent carrier. 0.51 mg of the test item was weighed and was dissolved in 5 mL Acetone. The stock solution was prepared to produce the only test item concentration. 0.200 mL of the test item was taken and were filled with dilution water to a volume of 2000 mL This solution was treated for 1 h in an ultrasonic bath and stirred for 24 h on a magnetic stirrer. The pH was measured to be 8.3.
100 mL of the solution were taken and 0.575 mL of the algal inoculum was added to each replicate resulting in a final cell density of 5000 cells/mL
For each test item concentration and the control 6 replicates were prepared. All flasks were sealed with cotton stoppers.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

Water hardness of the final nutrient medium was 1.3 °dH, corresponding to 22.5 mg/L CaCO3.

Test temperature:

21 - 24 °C

pH:

8.3.

Nominal and measured concentrations:

0.010 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.003 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Results [mg/L]:

Nominal concentration Analytical values
(geometric mean)
[mg/L] [mg/L]

ErC 50* (0-72 h): > 0.010 > 0.0032

ErC 10* (0-72 h): > 0.010 > 0.0032

NOEC [r]* (tα 0.05): ≥ 0.010 ≥ 0.0032

LOEC [r]* (tα 0.05): > 0.010 > 0.0032

Validity criteria fulfilled:

yes

Conclusions:

No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.

Executive summary:

No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.

 

Description of key information

No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.

 

Key value for chemical safety assessment

EC50 for freshwater algae:

0.003 mg/L

EC10 or NOEC for freshwater algae:

0.003 mg/L