Disodium 2,5-dichloro-4-[4-[[5-[[(dodecyloxy)carbonyl]amino]-2-sulphonatophenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September from 01st to 05th, and from 20th to 26th, 1997 (range finding and main test, respectively).

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

adopted 17 July, 1992

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Poecilia reticulata

Details on test organisms:

TEST ORGANISM
- Common name: guppy
- Length at study initiation: 1-3 cm

BREEDING
- Vessels: parental and young fish population was held in two 250 l glass aquaria.
- Illumination: 14 hours light.
- Temperature: 23 ± 2 °C
- Medium: continuously aerated and filtered tap water from Schlieren. The bottom of the aquaria was covered with gravel (<1.5 cm). Every month, one third of the total volume of the aquaria was replaced by fresh tap water.
- Feed: sera micropan, Sera vipan (Sera apanristic GmbH, D-52525 Heinsberg, Germany) daily. The fish were last fed 24 h before the start of the definitive test.
- Health check: during 7 days before the definitive test, mortality in the batch of which fish were used for the test was less than 5 %.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21 ± 1 °C

pH:

Vessels: 7.7 - 8.5
Control: 7.7 - 8.4

Dissolved oxygen:

Vessels: 6.8 - 8.3 mg/l
Control: 7.7 - 8.0 mg/l

Nominal and measured concentrations:

0.125, 0.250, 0.500, 1.00 and 2.00 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 1 l aquaria, all-glass.
- No. of organisms per vessel: 7 fish per test concentration.
- No. of vessels per concentration: 1 replicate.
- No. of vessels per control: 1 replicate.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water f rom Zürich-Schlieren, aerated.

OTHER TEST CONDITIONS
- Photoperiod: 14 h photoperiod a day, supplied by overhead white fluorescent tubes.

MEASUREMENTS
- Oxygen, pH, temperature: prior to the addition of fish to the test medium and after 2, 24, 48, 72 and 96 h of exposure
- Observations of the fish: made after 2, 24, 48, 72 and 96 h of exposure.
- Mortality: mortality of the fish was recorded at the same time intervals. Dead fish were removed immediately from the test medium and weight and length recorded.

RANGE FINDING TEST
- Concentration: 1, 10 and 100 mg/l
- No. of organisms per vessel: 3 fish per concentration.
- Results: 100 % mortality was observed at 100 and 10 mg/l after 2 h and at 1 mg/l after 24 h of exposure, respectively. No mortality was observed in the control after 96 h of exposure.

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.707 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

ln the definitive test all fish died at the nominal concentrations 2.00 and 1.00 mg/l after 24 hours of exposure.
No mortality was observed at 0.500, 0.250 and 0.125 mg/l, respectively and in the control after 96 hours of exposure.
Other toxic effects than mortality, e.g. loss of coordination, hypoactivity and swimming on the back, were not observed.
The no-observed-effect concentration (NOEC) was 0.500 mg/l.
100 % mortality was seen at the nominal concentration of 1.00 mg/l.

According to the physical data of the test substance provided by the supplier (negligible vapour pressure, sufficient stability and solubility in water) it was assumed that the nominal concentration has been satisfactorily maintained during the whole test procedure. Therefore, no analytical determination was conducted.

Sublethal observations / clinical signs:

Incidence of mortality observed.

Concentration	Number of dead fish observed at different points in time after start of exposure
	2 h	24 h	48 h	72 h	96 h
Control	0	0	0	0	0
0.125	0	0	0	0	0
0.250	0	0	0	0	0
0.500	0	0	0	0	0
1.00	1	6	-	-	-
2.00	6	1	-	-	-

Conclusions:

LC50 (96h): 0.707 mg/l (estimated on the basis of nominal conc.)

Executive summary:

The acute lethal toxicity of test item to Poecilia reticulata (Guppy) was investigated under static exposure conditions over a period of 96 h. 7 fish per concentration were exposed to the test substance.

The nominal concentrations as selected by a range finding test were 0.125, 0.250, 0.500, 1.00 and 2.00 mg/l, respectively. The individual test concentrations were prepared by dilution of a stock solution. No chemical analyses of the test concentrations were conducted.

In the definitive test all fish died at the nominal concentrations 2.00 and 1.00 mg/l after 24 h of exposure. No mortality was observed at 0.500, 0.250 and 0.125 mg/l, respectively, and in the control after 96 h of exposure. Other toxic effects than mortality, e.g. loss of coordination, hypoactivity and swimming on the back, were not observed.

Based on the data, the nominal lethal concentration of test item to Poecilia reticulata was calculated to be 0.707 mg/l. The no-observed-effect concentration (NOEC) was 0.500 mg/l. 100 % mortality was seen at the nominal concentration of 1.00 mg/l.

Conclusion

LC50 (96h): 0.707 mg/l (estimated on the basis of nominal conc.)

Description of key information

LC50 (96h): 0.707 mg/l (estimated on the basis of nominal conc.)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.707 mg/L

Additional information

The acute lethal toxicity of test item was investigated under static exposure conditions over a period of 96 h, using Poecilia reticulata.

The nominal concentrations were selected by a range finding test and were 0.125, 0.250, 0.500, 1.00 and 2.00 mg/l. The individual test concentrations were prepared by dilution of a stock solution. No chemical analyses of the test concentrations were conducted. In the definitive test, all fish died at the nominal concentrations 2.00 and 1.00 mg/l after 24 h of exposure. No mortality was observed at 0.500, 0.250 and 0.125 mg/l, respectively, and in the control after 96 h of exposure. Other toxic effects than mortality, e.g. loss of coordination, hypoactivity and swimming on the back, were not observed. Therefore, the LC50 (96h) resulted to be between 0.50 and 1.0 mg/l; the value was estimated to be 0.707 mg/l.

A second experiment conducted on Oncorhynchus mykjss, is available. A range-finding experiment was conducted at the nominal concentrations of 0.01, 0.10, 1.0, 10 and 100 mg/l; for the main test, 0.10 mg/l was selected as limit nominal concentration. 1 deaths was recorded in both the main experiment replicates, therefore the LC50 (96h) was indicated to be higher than 0.10 mg/l (nominal).

The outcomes for the two experiments are consistent: the LC50 (96h) value resulted to be between 1.0 and 0.5 mg/l.