Disodium [3-[4,5-dihydro-4-[(2-hydroxy-5-nitrophenyl)azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonato(3-)][1-[[2-hydroxy-5-(phenylazo)phenyl]azo]-2-naphtholato(2-)]chromate(2-)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Composite samples of each test concentration were drawn by mixing identical volumes of the test solutions taken from the approximate centre of the test vessels. They were taken immediately before exposure and after 48 hours exposure and kept at - 18 °C to - 22 °C until analysis.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Stain: Stauss 1820
- Source: CIBA-GEYGY Ltd., testing facility
- Feeding: none during the test
- Breeding: Cultures of daphnia are maintained in glass vessels containing approx. 2.5 L of reconstituted water at 20 ± 1 °C (water is renewed partially thrice weekly). At each renewal the daphnia are fed with a suspension of green algae (Scenedesmus subspicatus) supplemented by a suspension of TETRAMIN-extract in such quantities that the food is consumed after 24h.
- Pretratment: 24 hours before the begin of the exposure reproductive daphnia are separated from the young by sieving all individuals through a 800 µm sieve. This operation is repeated immediately before the exposure and the young (0-24h of age) are retained for the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

240 mg CaCO3/l

Test temperature:

20 ± 1 °C

pH:

7.9 - 8.1

Dissolved oxygen:

102 - 97 %

Nominal and measured concentrations:

Nominal concentrations: 4.4, 9.6, 21, 46, and 100 mg test substance/l

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers covered with watch glasses; 100 ml solution per beaker
- Aeration: none
- Lighting: fluorescent light, 16 hours daily approx. 1500 lux
- Number of daphnia: 20 per concentration and control
- Replicates: 4 replicates of 5 daphnia each
- blank: water

TEST MEDIUM / WATER PARAMETERS
Reconstituted water containing:
- 65 mg NaHCO3
- 294 mg CaCl2 dihydrate
- 123 mg MgSO4 eptahydrate
- 6 mg KCl
in 1000 ml bidistilled water

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

ca. 75 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL

Details on results:

other values:
EC0 (48h) = NOEC= 4,4 mg/L
EC100 (48h) = 46 mg/L

The measured test substance concentrations were within the range 100 ± 20 % of the nominal concentrations, therefore the results were calculated based on nominal concentrations.

Results with reference substance (positive control):

Immobilization in blank: 5 %

Conc. Nominal mg/l	Number of daphnia immobilized after 24h exposure				Number of daphnia immobilized after 48h exposure
	vessel 1	vessel 2	vessel 3	vessel 4	vessel 1	vessel 2	vessel 3	vessel 4
Blank	0	0	0	0	0	0	0	1
4,4	0	0	0	0	0	0	0	0
9,6	0	0	1	0	1	1	1	0
21	1	2	0	0	3	2	2	3
46	2	0	1	2	5	5	5	5
100	4	2	3	4	5	5	5	5

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48h) = 18 mg/l (nominal)

Executive summary:

The determination on ecotoxicity of the substance was determined in an Acute toxicity for Daphnia, test according to the guideline 92/69/EEC C.2. The test has been performed in compliance with the Procedures and Principles of Good Laboratory Practice. The test substance was tested on Daphnia magna Strauss 1820 for 48 hours.

20 daphnids (0-24 hours old) were exposed to nominal concentrations of 4.4, 9.6, 21, 46 and 100 mg test substance.

Results are:

EC50 (48 h) = 18 mg/l (nominal)

EC50 (24 h) calculated = 75 mg/l (nominal)

EC0 (48h) = NOEC = 4,4 mg/l (nominal)

EC100 (48h) = 46 mg/l (nominal)

Description of key information

EC50 (48 h) = 18 mg/l (nominal)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18 mg/L

Additional information

The short-term toxicity to invertebrates of the substance was determined in a short-term toxicity for Daphnia test, according to the guideline 92/69/EEC C.2. The test has been performed in compliance with the Procedures and Principles of Good Laboratory Practice. The test substance was tested on Daphnia Magna Strauss 1820 for 48 hours. 20 daphnids (0-24 hours old) were exposed to nominal concentrations of 4.4, 9.6, 21, 46 and 100 mg test substance. After 48b hours, no deaths occurred at the concentration of 4.4 mg/l. The EC50 at 48 hours has been staed to be 18 mg/l. The measured test substance concentrations were within the range 100 ± 20 % of the nominal concentrations, therefore the results were indicated based on nominal concentrations.