(RS)-3-Allyl-2-methyl-4-oxocyclopent-2- enyl (1R,3R)-2,2-dimethyl-3-(2-methyl prop-1-enyl)-cyclopropanecarboxylate (mixture of 2 isomers 1R trans: 1R/S only 1:3) (Esbiothrin)

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:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

liquid: viscous

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Purity : 96.8%

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Aerobic activated sludge from a wastewater treatment plant 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, therafter dried and the ration of wet to dry weight was calculated.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Details on study design:

Temperature: 22°C
Light regimen: darkness
pH at the start of the test: 7.2-7.4
pH at the end of the test: 7.1-7.8

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

< 60

Sampling time:

28 d

Details on results:

The biodegradation of the test item was calculated based on the theoretical oxygen demand (ThOD) of 2.54 mg O2/mg test item.
In one of the two flask of each test with the test item the biochemical oxygen demand (BOD) in the test media increased significantly after 11-13 days until test termination after 28 days. At the end of the 28-day exposure period, the biodegradation rate of allethrin was 37 (test I) and 61% (test II), respectively.
In the second flask from test II the BOD in the test medium increased starting on Day 26, reaching a biodegradation rate of 14% at Day 28. Only in one flask, no increase of the BOD was observed.
In no case, the pass level for ready biodegradability, i.e. a biodegradation rate of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was reached.

BOD5 / COD results

Results with reference substance:

The reference item was degraded by an average of 86-89% by exposure Day 14. At day 28, the reference item was degraded by an average of 92%.

Any other information on results incl. tables

The test item had no inhibitory effect on activated sludge microorganisms (biodegradation rate in both toxicity controls was >25% within 14 days) .

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The mean degradation rate (calculated as average over the degradation rates in all test vessels) was 28%. Allethrin was found to be not ready biodegradable under the test conditions within 28 days.