2-(2-oxopyrrolidin-1-yl)butyramide

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Batch: C02421 -1620
Purity: 98.6%

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test conditions

Details on test conditions:

The study was performed with aerobic activated sludge from a wastewater treatment plant (AW Ergolz 11,Fullinsdorf, Switzerland) treating predominantly domestic wastewater. The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.

Based on this ratio, an aliquot of washed sludge was suspended in tap water to obtain a concentration equivalent to 3 g dry material per liter. During the holding of three days prior to use, the sludge was fed daily with 50 mL synthetic wastewater* per liter and was kept at room temperature under continuous aeration until use. Immediately before use, the dry weight of the activated sludge was measured again in the inoculum used in the test. The pH of the activated sludge inoculum was adjusted from 8.3 to 7.6 with a diluted sulfuric acid solution.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Results with reference substance (positive control):

The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 20 mg/L (the 95% confidence limits were not calculable). The 3-hour EC50 is within the guideline-recommended range of 5-30 mg/L, confirming suitability of the activated sludge used.

Any other information on results incl. tables

Up to and including the highest concentration of 1000 mg/L, the test item ucb 6474 had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of 3 hours (Table 1 and Figure 1). The saturation concentration (water

solubility limit of ucb 6474 under the present test conditions) was reached and resulted in less than 15% inhibition after three hours contact time. Thus, the 3-hour NOEC of ucb 6474 was at the water solubility limit of ucb 6474 under the present test conditions, or 1000 mg/L.

This value might even be higher, but concentrations exceeding 1000 mg/L were not tested. The 3-hour EC20, EC50 and EC80 could not be calculated but were clearly higher than the water solubility limit of ucb 6474 under the present test conditions, or higher than 1000 mg/L.

The oxygen consumption rates of the two controls (run at the start and at the end of the test) differed by 8% (guideline-recommended maximum variation: 15%).

Applicant's summary and conclusion

Conclusions:

The test item ucb 6474 has no significant inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours up to and including the highest test item concentration of 1000 mg/L.