N-{[Benzyl(ethyl)amino]-[(chloro-cyano-nitrophenyl)substituted]phenyl}acetamide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

The inoculum was secondary effluent, collected from a treatment plant receiving predominantly domestic sewage. This effluent was used as test system as it is recommended in the guideline. A fresh sample of secondary effluent was collected from the treatment plant and was kept aerobic during transport.
This effluent was allowed to settle for one hour, decanted and the decanted effluent was used in the test.

Source of the Inoculum: Sewage Treatment Plant, Eurofins Advinus Limited, Bengaluru- 560058, India.

Determination of Bacterial Population in the Inoculum: The bacterial population in the inoculum was determined as colony forming units (CFU/mL) by diluting the inoculum to an appropriate dilution and then plating on nutrient agar plates.

Preconditioning of the Inoculum: The decanted effluent was preconditioned by aerating for 6 days at 22 to 24 °C.

Duration of test (contact time):

28 d

Initial conc.:

25 mg/L

Based on:

ThCO2

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

benzoic acid, sodium salt

Preliminary study:

Test Item Solubility: The test item formed a suspension in mineral medium at 250 mg/L.
Bacterial Population in the Inoculum: The bacterial population in the inoculum was 5.0 x 10^7 CFU/L.

Parameter:

% degradation (CO2 evolution)

Value:

8.3

Sampling time:

28 d

Details on results:

The percent degradation of test item was 8.00% and 8.59% in the Flask No. 1 and 2, respectively at the end of the test. The mean percent degradation of test item was 8.30% at the end of test.

Results with reference substance:

The percent degradation of reference item was 100.29% and the toxicity control was 54.71% at the end of the test.

VALIDITY OF THE TEST

For the test to be valid, the following performance criteria were applied:

 

At the end of the test, the degradation of the test item at the plateau was 8.00% in Flask 1 and 8.59% in Flask 2, respectively. The per cent difference in test item flask replicates was 7.11% as against the guideline requirement of less than 20% difference.

 

The degradation of reference item was 70.62% on Day 13 as against the guideline requirement of at least 70% degradation of reference item by Day 14 of treatment.

 

The inorganic carbon (IC) content of the mineral medium at the beginning of the test was zero. The total CO2 evolution in the inoculum blank throughout the test was 37.52 mg/L, as against the guideline requirement that the total CO2 evolution should not normally exceed 40 mg/Lmedium.

 

There was 42.61% degradation [based on ThCO2] in the toxicity control flask on Day 13 as against the guideline requirement that, in a toxicity test, containing both the test item and a reference item, if less than 25% ThCO2 occurs within 14 days, the test substance can be assumed to be inhibitory. This shows the test item is not inhibitory to the test system.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

FAT 41047/A TE was found to be not readily biodegradable as 8.30% mean degradation was achieved at the end of test which is less than 60% pass level in 10-day window period within the 28-d period of the test.

Executive summary:

The ready biodegradability of FAT 41047/A TE was tested using the CO2 Evolution Test (OECD Test guideline 301B).

The test item was added to two test vessels at the concentration of 25 mg/L (equivalent to 15.1 mg of Total Organic Carbon/L). Two control treatments containing only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each test vessel. The residual barium hydroxide was measured on Days 3, 6, 8, 10, 13, 16, 20, 24, 27 and 29 after the initiation of the test.

 

The mean percent degradation of test item was 8.30% at the end of test while, the percent degradation of reference item was 100.29% and the toxicity control was 54.71% at the end of the test. It was observed that the mean degradation of test item, FAT 41047/A TE was 8.30% which is less than 60% pass level in 10-day window period within the 28-d period of the test.

The test fulfilled all the validity criteria.

Based on the results, it was concluded that the test item, FAT 41047/A TE is not readily biodegradable as 8.30% mean degradation was achieved at the end of test which is less than 60% pass level in 10-day window period within the 28-d period of the test.

Description of key information

FAT 41047/A TE is not readily biodegradable as 8.30% mean degradation was achieved at the end of test which is less than 60% pass level in 10-day window period within the 28-d period of the test.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of FAT 41047/A TE was tested using the CO2 Evolution Test (OECD Test guideline 301B).

The test item was added to two test vessels at the concentration of 25 mg/L (equivalent to 15.1 mg of Total Organic Carbon/L). Two control treatments containing only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each test vessel. The residual barium hydroxide was measured on Days 3, 6, 8, 10, 13, 16, 20, 24, 27 and 29 after the initiation of the test.

 

The mean percent degradation of test item was 8.30% at the end of test while, the percent degradation of reference item was 100.29% and the toxicity control was 54.71% at the end of the test. It was observed that the mean degradation of test item, FAT 41047/A TE was 8.30% which is less than 60% pass level in 10-day window period within the 28-d period of the test.

Based on the results, it was concluded that the test item, FAT 41047/A TE is not readily biodegradable as 8.30% mean degradation was achieved at the end of test which is less than 60% pass level in 10-day window period within the 28-d period of the test.