Ethanone, 1-(1-chlorocyclopropyl)-

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:

13 Jul - 10 Aug 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: secondary effluent of a domestic sewage treatment plant (Klaranlage Odenthal)
- Preparation of inoculum for exposure: seperation of coarse particles by filtration and aeration of mineral medium plus inoculum (filtrate) for 7 days
- Concentration of effluent: 5 ml/L
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

4.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral medium
- Test temperature: 20±1°C
- pH adjusted: no
- Aeration of dilution water: mineral medium plus inoculum were aerated for 7 days
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: closed bottles
- Number of culture flasks/concentration: 10
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: day 0, 7, 14, 21 and 28
- Sampling method: not specified

CONTROL AND BLANK SYSTEM
- Inoculum blank: A measured volume of mineral medium containing only inoculum.
- Abiotic sterile control: not used
- Toxicity control: Toxic effects of the test substance was determined in a toxicity control flask containing test substance, reference substance and inoculum.
- Reference control: in order to check the procedure, the reference chemical sodium benzoate is tested by setting up 2 flasks in parallel to the normal test runs.

Reference substance:

benzoic acid, sodium salt

Test performance:

All validity criteria of the test method were met

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Results with reference substance:

The reference compound showed 100 % degradation after 14 days.

Validity criteria for the measurement of the biodegradation:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
Normally, the test lasts for 28 days. Tests however may be ended before 28 days, i.e. as soon as the biodegradation curve has reached a plateau for at least three determinations.	The test was conducted for 28 days	Yes
In order to check the procedure, reference compounds which meet the criteria for ready biodegradability are tested by setting up an appropriate vessel in parallel as part of normal test runs. Suitable compounds are aniline (freshly distilled), sodium acetate and sodium benzoate.	Sodium benzoate was tested as reference substance	Yes
A test is considered valid if the difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20% and if the percentage degradation of the reference compound has reached the pass levels by day 14.	The difference between the two measured values of the test substance are within 20% variation. The percentage degradation of the reference substance reached 100% degradation by day 14.	Yes
If in a toxicity test, containing both the test substance and a reference compound, less than 35% degradation (based on total DOC) or less than 25% (based on total ThOD or ThCO2) occurred within 14 days, the test substance can be assumed to be inhibitory. The test series should be repeated, using a lower concentration of test substance (if this can be done without seriously impairing the accuracy of the DOC determination) and/or a higher concentration of inoculum, but not greater than 30 mg solids/l.	Percentage degradation in the toxicity control was 40% at day 14	Yes
Oxygen depletion in the inoculum blank should not exceed 1.5 mg/L after 28 days. Values higher than this require investigation of the experimental techniques. The residual concentration of oxygen in the test bottles should not fall below 0.5 mg/L at any time. Such low oxygen levels are valid only if the method of determining dissolved oxygen used is capable of measuring such levels accurately.	Oxygen depletion in the inoculum blank did not exceed 1.5 mg/L dissolved oxygen after 28 days.	Yes

Validity criteria fulfilled:

yes

Remarks:

See more details in the table in the section "Any other information on results incl. tables"

Interpretation of results:

not readily biodegradable

Conclusions:

Within 28 days, a degradation of 1 % was determined for the test substance.

Executive summary:

The ready biodegradability of the test substance was assessed in accordance with with the Council Directive 92/69/EEC Method C.4-E "Closed Bottle Test". The test substance in a mineral medium was inoculated with secondary sewage effluent and incubated for 28 d under aerobic conditions in closed bottles.The consumption of oxygen was determined by measuring the quantity of oxygen expressed as a percentage of theoretical oxygen demand (ThOD). The oxygen demand values of the test item after 28 days were corrected for uptake by the blank inoculum run in parallel. Percentage biodegradation of the test substance was 1 % after 28 days and the reference compound showed 100 % degradation after 14 days. Therefore, the test substance is considered to be "Not Readily Biodegradable". 

Description of key information

The ready biodegradability of the test substance was assessed in accordance with with the Council Directive 92/69/EEC Method C.4-E "Closed Bottle Test". The test substance in a mineral medium was inoculated with secondary sewage effluent and incubated for 28 d under aerobic conditions in closed bottles.The consumption of oxygen was determined by measuring the quantity of oxygen expressed as a percentage of theoretical oxygen demand (ThOD). The oxygen demand values of the test item after 28 days were corrected for uptake by the blank inoculum run in parallel. Percentage biodegradation of the test substance was 1 % after 28 days and the reference compound showed 100 % degradation after 14 days. Therefore, the test substance is considered to be "Not Readily Biodegradable". 

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater