ethyl 2-{[(2,6-difluorophenyl)methyl](ethoxycarbonyl)amino}-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

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:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 2-[[(2,6-difluorophenyl)methyl](ethoxycarbonyl)amino]-4-methyl-5-(4-nitrophenyl)-3-thiophenecarboxylate

EC Number:

840-148-0

Cas Number:

308831-94-9

Molecular formula:

C24H22F2N2O6S

IUPAC Name:

Ethyl 2-[[(2,6-difluorophenyl)methyl](ethoxycarbonyl)amino]-4-methyl-5-(4-nitrophenyl)-3-thiophenecarboxylate

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Type of inoculum: aerobic mixed bacterial culture
Source: Municipal wastewater treatment plant, Esztergom-Kertváros

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Preparation of inoculum test culture:
Before the test 300 ml stock culture was filtered through a filter with 0.2 mm pore size to remove the bigger insoluble particles and then the dry substance content of the filtrate was determined. The measured value was 3.94 g/L. For preparing the inoculum culture 149 ml mineral medium was added to 51 ml filtered stock culture. The calculated dry mass of inoculum culture was 1 g/L.

Preparation of test vessels:
Following test vessels were prepared and analysed for the study:
- Test item (in two replicates)
- Blank control (in two replicates)
- Reference solution (positive control)
- Reference and test item solution (toxicity control)
- Sterilized solution of test item (abiotic control)

Test item:
The test item was measured directly into the test vessels.

Blank Control:
The endogenous activity of the inoculum was determined by blanks with inoculum but without test and reference items.

Positive Control:
The positive control was used for proving the suitability of inoculum culture. For the reference solution 320.32 mg sodium acetate was diluted in 100 ml mineral medium.

Toxicity control:
The possible toxic effect of the test item was determined by preparing a test vessel containing both test and reference item at the same concentrations as in the individual vessels for test item and reference solution.

Abiotic control:
15.01 mg sterilising agent (Mercury(II) sulphate) was added into the test vessel for check of the possible abiotic degradation of the test item. Abiotic control did not contain any inoculum.

Reference substance

Reference substance:

other: sodium acetate

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

28 d

Remarks on result:

other: mean of two replicates

BOD5 / COD results

Results with reference substance:

Reference substance (positive control): 80 %/28 days.
The results indicate that the used inoculum was in good condition as the biodegradability of the reference item reached 65% at the 14th day.
The percentage of degradation of the reference item has reached the pass level by day 14 (≥ 60%).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Based on ready biodegradability testing results the ethyl 2-[[(2,6-difluorophenyl)methyl](ethoxycarbonyl)amino]-4-methyl-5-(4-nitrophenyl)-3-thiophenecarboxylate is not readily biodegradable.