Tetrasodium {5-[(4-chloro-6-{[4-(alkenylsulfonyl)phenyl]amino}-heteromonocycl-2-yl)amino]-4-(hydroxy-κO)-3-{[2-(hydroxy-κO)phenyl]diazenyl-κN}naphthalene-disulfonato(4-)}[3-(hydroxy-κO)-4-{[2-(hydroxy-κO)naphthalen-1-yl]diazenyl-κN}naphthalene-sulfonato(3-)]chromate(4-)

Toxicity to aquatic algae and cyanobacteria

Description of key information

Determination of the acute toxicity of FAT 20341/A TE on algal growth inhibition.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

50 mg/L

Additional information

The study was performed to assess the effect of FAT 20341/A TE on the growth of the green alga Pseudokirchneriella subcapitata. 

Following preliminary range-finding tests,Pseudokirchneriella subcapitatawas exposed to an aqueous solution of FAT 20341/A TE at concentrations of 6.25, 12.5, 25, 50 and 100 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C.

 

Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter^®Multisizer Particle Counter.

 

Analysis of the test preparations at 0 and 72 hours showed measured test concentrations to range from 97% to 108% of nominal and so the results are based on nominal test concentrations only.

 

Exposure ofPseudokirchneriella subcapitatato the test item gave the following results:

 

Response Variable	EC50(mg/L)	No Observed Effect Concentration (NOEC) (mg/L)	Lowest Observed Effect Concentration (LOEC) (mg/L)
Growth Rate	>100*	50	100
Yield	71	50	100

* It was not possible to calculate an E_rC₅₀value as no concentration tested resulted in greater than 50% inhibition of growth rate.