Chromate(5-), bis[4-(hydroxy-κO)-7-[2-(2-hydroxy-1-naphthalenyl)diazenyl]-3-[2-[2-(hydroxy-κO)- 3-nitro-5-sulfophenyl]diazenyl]-2-naphthalenesulfonato(4-)]-, sodium (1:5)

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:

During the final test duplicate samples were taken from 0 and 100 mg/l for analysis.
Sampling:
-Frequency: at t=0 h and t=48 h.
-Volume: 10 ml from the approximate centre of the test vessel.
-Storage: the samples were transferred to Analytical chemistry directly after sampllng.
Additionally, reserve samples of 25 ml were taken from all concentrations. These samples were stored in a deep freezer for possible analysis until delivery of the final report.

SAMPLE PRETREATMENT
-Storage: All samples not analysed on the same day of sampling were frozen until analysis.
-Sample pretreatment: the frozen samples were defrosted at room temperature. The samples of 0 mg/l were not pretreated. The entire volume of each sample of 100 mg/l was transferred quantitatively into a suitable volumetric flask. The flask was filled up to the mark with Mllli-Q water. If necessary, the solutions were further diluted using Milli-Q water to obtain concentrations in the calibration range.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
-Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
-Age of parental stock: < 24 hours
-Feeding during test: No feeding

ACCLIMATION
-Start of each batch: with newborn animals, i.e. less than 3 days old, by placing about 250 of them into 10 litres of medium in an all-glass culture vessel.
-Maximum age of the cultures: 4 weeks.
-Renewal of the cultures: after 7 days of cultivation half of the volume medium twice a week.
-Temperature: 18-22 °C
-Feeding : a suspension of fresh water algae.
-Frequency: once a day.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

250 mg/l expressed as CaCO3

Test temperature:

19 - 20.5 °C

pH:

8.0 ± 0.2

Dissolved oxygen:

8.7 - 9.4 mg O2/l

Nominal and measured concentrations:

0 and 100 mg/l

Details on test conditions:

TEST SYSTEM
-Test vessel: 100 ml, all-glass
-Type (delete if not applicable): closed
-Aeration: no aeration of the test solution, except when the presence of test substance induces oxygen depletion.
-No. of organisms per concentration: 20
- Loading: 10 per vessel containing 100 ml medium
-No. of vessels per concentration (replicates): 2
-No. of vessels per control: 1

TEST MEDIUM
-Source/preparation of dilution water: ISO M4, prepared in milli-RO water
The test media were prepared using a stock solution of 100 mg/l by adding quantltatlvely 25.2 mg of test substance to 250 ml ISO-medlum.
The final test solution was black (bluish according to observatlons 1n the range-flnding test) and opaque.

OTHER TEST CONDITIONS
-Photoperiod: 16 hours photoperiod daily

RANGE-FINDING STUDY: yes
-Test concentrations: 0.1 and 100 mg/l (forming a geometric progression with a factor of 10)
-Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

-Range-flnding test: no significant (> 10 %) immobility of daphnia was seen at any of the concentrations tested
-Final study: due to the opacity of the test solution at 24 h, it was not possible to observe the Daphnia. Therefore, the EC50 (24 h) could not be determined. It was assumed that the value measured at 24 h was the same as determined at 48 h.
-Acceptability of the test: in the control, no daphnia became immobilized or trapped at the surface of the water. Further, all test conditions remained within the ranges prescribed by the protocol.
-The actual test concentrations were > 89 % of nominal throughout the 48-hour exposure period.

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48 h) > 100 mg/l

Executive summary:

The acute toxicity of the test item to aquatic invertebrates was assessed in Daphnia magna according to the method C.2 of EEC-Directive 92/69 EEC. Based on the results of a range-finding test, twenty young daphnis were exposed to a nominal test substance concentration 100 mg/l for a period of 48 hours.

Due to the opacity of the test solution at 24 h, it was not possible to observe the Daphnia. It was assumed that the value measured at 24 h was the same as determined at 48 h.

The EC50 (48 h) was found to be greater than 100 mg/l.

 

Description of key information

EC50 (48 h) > 100 mg/l

Additional information

The acute toxicity of the test item to aquatic invertebrates was assessed in Daphnia magna according to the method C.2 of EEC-Directive 92/69 EEC. Based on results of a range-finding test, twenty young daphnis were exposed to a nominal test substance concentration 100 mg/l for a period of 48 hours.

The EC50 (48 h) was found to be greater than 100 mg/l.