tetrasodium 2-(4-fluoro-6-(methyl-(2-(sulfatoethylsulfonyl)ethyl)amino)-1,3,5-triazin-2-ylamino)-5-hydroxy-6-(4-methyl-2-sulfonatophenylazo)naphthalene-1,7-disulfonate

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:

From October 26, 1999 to October 29, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analysis of the only test concentration (with and without algal inoculum) plus a control at 0 and after 72 h of exposure.

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: CHODAT
- Source (laboratory, culture collection): Institute of Plant Physiology at the University of Gottingen (Germany)
- Method of cultivation: The algal cultures were taken from an exponentially-growing pre-culture and were mixed with the nutrient medium to make up to a final cell density of about 10E4 cells/mL in the test medium.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

pH:

Control:
0 h = 7.8; 72 h = 10.4

Test:
0 h = 7.8; 72 h = 10.4

Nominal and measured concentrations:

- Method of administration: direct weighing
- Test concentration: 100 mg/L (nominal) with algae
- Measured concentration: 106 mg/L (including organic + inorganic components of the test substance)

Details on test conditions:

- Test vessel: Erlenmeyer flasks (300 mL) with stoppers containing 100 mL of test medium
- Cultivation (stock cultures, precultures, test cultures): In a light chamber at 23±2°C and with a quantum flux of 120 µE/m2.s
- Cell counting: Microcellcounter Sysmex F-300 Digitana (SOP 2030-0001903-98 D)

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

other: EbC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Table 1:

Treatment group	Nominal concentration of test substance (mg/L)	Measured concentration of test substance including organic and inorganic components (mg/L)	Percentage inhibition of cell growth [b]	Percentage inhibition of mean growth rate [r]
Control	0	0	-	-
Test substance	100	106	10.6	0.0

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study, the 72 h EbC50 (biomass) and ErC50 (growth rate) for Scenedesmus subspicatus were found to be >100 mg/L test substance (nominal concentration). Further, the NOEC for growth rate was found to be 100 mg/L (nominal) test substance.

Executive summary:

A study was conducted to determine the acute toxicity of the test substance to the algae Scenedesmus subspicatus (new name: Desmodesmus subspicatus) according to EU Method C.3, in compliance with GLP.

Innocula of the algae were exposed to a nominal concentration of 100 mg/L test substance for 72 h under static conditions. Quantification of the applied concentration was carried out using TOC determination at 0 and 72 h. The cell densities were measured at 24 h intervals. Inhibition of the algal population was measured as reduction in growth and growth rate, relative to control cultures grown under identical conditions.

 

The measured concentration of the test substance was 106% of nominal values at 72 h. Under the conditions of the study, the 72 h EbC50 (biomass) and ErC50 (growth rate) for Scenedesmus subspicatus were >100 mg/L (nominal). The NOEC for growth rate was 100 mg/L (nominal).

Description of key information

Under the conditions of the study, the 72 h EbC50 (biomass) and ErC50 (growth rate) for Scenedesmus subspicatus were found to be >100 mg/L test substance (nominal concentration). Further, the NOEC for growth rate was found to be 100 mg/L (nominal) test substance.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

A study was conducted to determine the acute toxicity of the test substance to the algae Scenedesmus subspicatus (new name: Desmodesmus subspicatus) according to EU Method C.3, in compliance with GLP. Innocula of the algae were exposed to a nominal concentration of 100 mg/L test substance for 72 h under static conditions. Quantification of the applied concentration was carried out using TOC determination at 0 and 72 h. The cell densities were measured at 24 h intervals. Inhibition of the algal population was measured as reduction in growth and growth rate, relative to control cultures grown under identical conditions.The measured concentration of the test substance was 106% of nominal values at 72 h. Under the conditions of the study, the 72 h EbC50 (biomass) and ErC50 (growth rate) for Scenedesmus subspicatus were >100 mg/L (nominal). The NOEC for growth rate was 100 mg/L (nominal) (Caspers, 1999b).