Trisodium bis[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonato(3-)]chromate(3-)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

November 14, 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The test was conducted by means of Read Across approach. The reliability of the source study report is 1. Further information was attached at section 13

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Principles of method if other than guideline:

Guidelines followed

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

No data

Vehicle:

not specified

Details on test solutions:

M4 medium

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: RCC Ltd.
- Age at study initiation (mean and range, SD): Young Daphnids, aged less than ‘24’ hours old

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

Not available

Hardness:

220 mg/L

Test temperature:

20.4 °C

pH:

7.59 - 7.70

Dissolved oxygen:

7.43 – 7.66 mg/L

Salinity:

Not available

Nominal and measured concentrations:

Range finding experiment
0.001, 0.01, 0.1, 1, 10, 50 and 100 mg/l.

Main experiment
1, 1.5, 2.3, 3.4, 5.1, 7.6 and 11.4 mg/l, fixed in a geometric series with a separation factor of 1.5.

Details on test conditions:

TEST SYSTEM
- No. of organisms per vessel: 10 daphnids

Reference substance (positive control):

yes

Remarks:

Potassium Dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

3.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.11 mg/L

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

5.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Upper confidence limits of 6.63 mg/L and lower confidence limits of 5.64 mg/L and regression equation Y = -1.3294 + 8.0509 log (x).

Results with reference substance (positive control):

EC50 of Potassium Dichromate Pure was calculated as 1.72 mg/L with upper confidence limits of 2.12 mg/L and lower confident limits of 1.40 mg/L and regression equation Y = 4.0957 + 3.8604 log (x). At ‘48’ hour, the EC50 was calculated as 1.33 mg/L with upper confidence limits of 1.63 mg/L and lower confidence limits of 1.08 mg/L and regression equation Y = 4.5239 + 3.8769 log (x).

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48h) = 6.11 mg/l
NOEC = 3.4 mg/l
LOEC = 5.1 mg/l

Executive summary:

Method

Acute Immobilization Toxicity Study in Daphnia magna was conducted in accordance with OECD guideline 202. Test item was soluble and hence formulated in M4 medium. Based on the results of the range finding experiment, main experiment was conducted with a range of concentrations viz., 1, 1.5, 2.3, 3.4, 5.1, 7.6 and 11.4 mg/l.

Observations

No immobilization was observed in control and daphnids exposed to 1, 1.5 and 2.3 mg/l test concentrations throughout the experimental period. At the end of 24 hour, no immobility was observed in daphnids exposed to any of the test concentrations. Thus, the percent immobilisation at the end of 24 hour was recorded to be 0 % in control and daphnids exposed to all the test concentrations. At the end of 48 hour, 2/40, 8/40, 31/40 and 40/40 immobility was recorded in the daphnids exposed to 3.4, 5.1, 7.6 and 11.4 mg/l concentration respectively. Thus the percent cumulative immobilisation at the end of 48 hour was recorded to be 0 % in control and daphnids exposed to 1, 1.5 and 2.3 mg/L test concentration whereas, 5 %, 20 %, 77.5 % and 100 % was observed in daphnids exposed to 3.4, 5.1, 7.6 and 11.4 mg/l concentrations respectively.

Conclusion

Based on the test results, the EC50 of the test substance in Daphnia magna observed for a period of 48 hour was calculated as 6.11 mg/l. The no observed effect concentration (NOEC) was calculated as 3.4 mg/L and the low observed effect concentration (LOEC) was calculated as 5.1 mg/l.

Description of key information

EC50 (48 h) = 6.11 mg/l

NOEC = 3.4 mg/l

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

6.11 mg/L

Additional information

No studies on the "short term toxicity to aquatic invertebrates" are available for the substance in itself nevertheless, a study was conducted with an analogue molecule (Similar Substance 01). Further information are reported in the Read Across justification attached to section 13.

The test was conducted in accordance with OECD Guidelines 202, to assess the effect of the test substance. Based on the results of a range finding experiment the test concentrations were set as follows: 1, 1.5, 2.3, 3.4, 5.1, 7.6 and 11.4 mg/l. Four replicates each, containing 10 daphnids were held for each test concentration and a control group. Analysis of the test preparations at 0 and 48 hours showed measured concentrations to be near nominal and so the results are based on nominal concentrations only.   Based on the test results, the EC50 of the test substance in Daphnia magna observed for a period of 48 hour was calculated as 6.11 mg/l. The no observed effect concentration (NOEC) was calculated as 3.4 mg/l and the low observed effect concentration (LOEC) was calculated as 5.1 mg/l.