Equimolecular mixture of - Disodium 2-Hexadecylsulfanyl-1-(4-sulfo-butyl)-1H- benzoimidazole-5-sulfonate - Disodium 2-Hexadecylsulfanyl-3-(4-sulfo-butyl)-1H- benzoimidazole-5-sulfonate

Short-term toxicity to aquatic invertebrates

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

452-830-1

EC Name:

-

Molecular formula:

C27 H44 N2 Na2 O6 S3

IUPAC Name:

Equimolecular mixture of - Disodium 2-Hexadecylsulfanyl-1-(4-sulfo-butyl)-1H- benzoimidazole-5-sulfonate - Disodium 2-Hexadecylsulfanyl-3-(4-sulfo-butyl)-1H- benzoimidazole-5-sulfonate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Analysis was performed on samples at the start and after 48h of exposure.

Test solutions

Vehicle:

no

Details on test solutions:

The test substance is completely soluble in the test medium at the concentrations tested.
Concentrations tested: 2.2, 4.6, 10, 22 and 46mg/l.

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

180mg/l (expressed as CaCO3)

Test temperature:

between 20.5 and 21.1 °C

pH:

8.0

Dissolved oxygen:

8.6 - 9.0mg/l

Salinity:

Several macro salts are dissolved in tap water purified by reverse osmosis.

Nominal and measured concentrations:

Analysis of the samples taken at the start of the final test showed that the measured concentratinos were in agreement with nominal (80-93% of nominal) and remained stable during the entire test period (91-98% of initial). Based on these results the effect concentrations were expressed in terms of the analytically confirmed nominal concentrations.
Final nominal concentrations: 2.2, 4.6, 10, 22 and 46 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: measured in agreement with nominal and stable during entire test period

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

19 mg/L

Nominal / measured:

nominal

Conc. based on:

other: measured in agreement with nominal and stable during entire test period

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval: 13 - 29 mg/l

Details on results:

No daphnids were immobilized in the control treatment. The percentage of immobilized daphnids increased with the concentrations tested (from 2.2 to 46mg/l).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study the substance induced acute immobilisation of Daphnia magna. The 48-h EC50 was 19 mg/L (95% CI: 13-29 mg/L).