N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-oxobutyramide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-12-18 to 2009-07-17 (experimental: 2009-02-10 to 2009-02-13)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to current OECD-Guidelines and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-oxobutyramide

EC Number:

247-820-7

EC Name:

N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-oxobutyramide

Cas Number:

26576-46-5

Molecular formula:

C11H11N3O3

IUPAC Name:

3-oxo-N-(2-oxo-2,3-dihydro-1H-benzimidazol-5-yl)butanamide

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

Stock solution: 200 mg/L, freshly prepared with dilution water
Dispersion treatment: Ultrasound, 30 min at 40°C
Test concentration: A limit concentration of 100 mg/L was tested.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Origin: Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Nikolausberger Weg 18, D-37073 Göttingen

Cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted 35-70 µE m^(-2) s^(-1) for 24 hrs per day.

Culture medium: Nutrient medium Z according to Lüttge et al.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Hardness:

0.24 mmol Ca+Mg / L

Test temperature:

Nominal range: 21 - 24 °C, controlled at +/- 2 °C

pH:

8.1 +/- 0.2

Nominal and measured concentrations:

Nominal concentration Measured concentration
Test start Test End
Test item (mg/L) Main comp. (mg/L) Conc. (mg/L) RR (%) Conc. (mg/L) RR (%)
100 99.5 99.5 100 80.8 81
RR = Recovery rate related to the concentration of the main component

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterile Erlenmeyer flasks, volume 250 ml sealed with cotton wool plugs
- Six replicates per limit concentration and control
- Test volume: 100 ml
- Agitation: Test containers were placed on a rotary shaker and oscillated at approximately 70 rpm.
- Light intensity: 60-120 µE m^(-2) s^(-1)
- Light regime: 24 h/d light

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (Sigma), CAS 7778-50-9, Purity: 99.5%

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Yield inhibition

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Rate-related inhibition

Results with reference substance (positive control):

EC50: 0.69 mg/L (Rate-related inhibition)
EC50: 0.31 mg/L (Yield inhibition)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No inhibiting effects on specific growth rate and yield were found in the limit concentration of 100 mg/l. The EC50-values for specific growth rate inhibition and inhibition of yield after 72 h were > 100 mg/L.

Executive summary:

Due to the result of this study the test item is not subject for classification concerning the Algae toxicity