1,7-Naphthalenedisulfonic acid, 2-[[4-chloro-6-(cyanoamino)-1,3,5-triazin-2-yl]amino]-5-hydroxy-6-[2-[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, lithium sodium salt (1:?:?)

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 Oct. 26, 1999 to Jan. 18, 2000

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 test concentrations 12.5, 25, 50, 100 mg/L plus a control; additional analysis of the highest (100 mg/L) and the lowest analytically detected test concentration (12.5 mg/L) without algal inoculum, at test start and after 72 h exposure.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: From stock solution (125 mg/mL)

-Control: Inoculum in nutrient medium and water for dilution

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, University of Gottingen (Germany)
- Method of cultivation: In a light chamber at 23 ± 2 °C and with a quantum flux Which equals 120 µE/m2.s.

ACCLIMATION
- Any deformed or abnormal cells observed: No

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

None

pH:

7.8-10.4

Nominal and measured concentrations:

Nominal: 1.6, 3.2, 6.3, 12.5, 25, 50 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: 300 mL Erlenmeyer flasks, 100 mL of test medium
- Aeration: Yes
- Algal suspension taken from an exponentially growing preculture which serves to adjust an initial cell density of 10 000 cells per mL.



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionized water



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber (Microcellcounter sysmex F-300 Digitana)


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

51 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 38-75

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: -

Duration:

72 h

Dose descriptor:

EC0

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: cell density

Remarks on result:

other: -

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

6.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: cell density

Remarks on result:

other: -

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No

Please refer to 'Attached background material' for the results on the analysis

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Dunnett test: NOEC, LOEC
Probit analysis

The test concentrations 1.6, 3.2 and 6.3 mg/L were below the detection limit of the TOC method (2 mg/L). Analytically determined values of the higher concentrations (25, 50 and 100 mg/L) exhibited close adherence to nominal values, recovery rates ranging from 99.08 to 129 %.

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, the 72 h EbC50 and ErC50 of the test substance were 51 and >100 mg/L respectively. The NOEC of the test substance was determined to be 3.2 mg/L.

Executive summary:

A study was performed to assess the adverse effects of test substance on the growth and growth rate of green algae species Scenedesmus subspicatus CHODAT over several generations. The study was conducted in accordance with EU Method C.3. in compliance with GLP.

 

Exponentially growing algal cells were exposed for a period of 72 h to the nominal test concentrations of 1.6, 3.2, 6.3, 12.5, 25, 50 and 100 mg/L of test substance dissolved in water.

Analysis of the test concentrations 12.5, 25, 50, 100 mg/L plus a control; additional analysis of the highest (100 mg/L) and the lowest analytically detected test concentration (12.5 mg/L) without algal inoculum, at the test start and after 72 h exposure.

 

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.

 

Under the test conditions, the 72 h EbC50 and ErC50 of the test substance were 51 and >100 mg/L respectively. The NOEC of the test substance was determined to be 3.2 mg/L.

 

Description of key information

The 72 h EbC50 and ErC50 of the test substance were 51 and >100 mg/L respectively. The NOEC of the test substance was determined to be 3.2 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

3.2 mg/L

Additional information

A study was performed to assess the adverse effects of test substance on the growth and growth rate of green algae species Scenedesmus subspicatus CHODAT over several generations. The study was conducted in accordance with EU Method C.3.

Exponentially growing algal cells were exposed for a period of 72 h to the nominal test concentrations of 1.6, 3.2, 6.3, 12.5, 25, 50 and 100 mg/L of test substance dissolved in water.

Analysis of the test concentrations 12.5, 25, 50, 100 mg/L plus a control; additional analysis of the highest (100 mg/L) and the lowest analytically detected test concentration (12.5 mg/L) without algal inoculum, at the test start and after 72 h exposure.

 

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.

 

The 72 h EbC50 and ErC50 of the test substance were 51 and >100 mg/L respectively. The NOEC of the test substance was determined to be 3.2 mg/L (Dr. Caspers, 2000).