1-butoxy-2,3-difluorobenzene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 FEB 2003 - 12 MAY 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted July 17, 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Commission Directive 92/69/EEC, Method C.4-D of July 31, 1992: Manometric Respirometry Test (EEC Publication No. L 383 A, December 1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, Landwirtschaft und Forsten, Mainzer Strafle 80, 65189 Wiesbaden, Germany, 10. Juni 2002

Test material

Test material information

Constituent 1

Reference substance name:

1-butoxy-2,3-difluorobenzene

EC Number:

446-810-1

EC Name:

1-butoxy-2,3-difluorobenzene

Cas Number:

136239-66-2

Molecular formula:

Hill formula: C10H12F2O CAS formula: C10H12F2O

IUPAC Name:

1-butoxy-2,3-difluorobenzene

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge, micro organisms from a domestic waste water treatment plant, supplied by the sewage plant Groß-Zimmern, Germany.
- Preparation of inoculum for exposure: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.
- Concentration of sludge: 1.5 g dry material per litre
- Water filtered: no

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

OECD TG 301 F

TEST CONDITIONS
- Test temperature: 21 °C
- pH: 7.7 - 7.9
- pH adjusted: no
- Aeration of dilution water: continous stirring
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Manometric Test System with test flasks containing a volume of 500mL
- Number of culture flasks/concentration: 2 (Test item), 2 (Inoculum control), 1 (Procedure control, Abiotic control, Toxicity control)
- Method used to create aerobic conditions: continous stirring
- Measuring equipment: The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System, Aqualytic, 63231 Neu Isenburg, Germany) each day.
- CO2 trap: Evolved carbon dioxide was absorbed in an aqueous solution (45 %) of potassium hydroxide
- Test performed in open system: no

CONTROL AND BLANK SYSTEM
- Inoculum blank: Activated sludge at a concentration of 30 mg suspended solids per litre was filled up with test water to a volume of 244 mL.The oxygen demand of the inoculum control (medium and inoculum) was 30 mg O2/L and thus not greater than 60 mg O2/L within 28 days.
- Abiotic sterile control: 25.4 mg of test item filled up with test water (sterile filtered, 0.2 - 0.45 µm filter) to a volume of 244 mL.
- Toxicity control: 25.7 mg of the test item), 25.4 mg Aniline and activated sludge at a concentration of 30 mg suspended solids per litre were filled up with test water to a volume of 244 mL.
- Other: Procedure Control: 25.7 mg Aniline and activated sludge at a concentration of 30 mg suspended solids per litre were filled up with test water to a volume of 244 mL. The procedure control was also used for other projects which ran in parallel.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

7

Sampling time:

28 d

Details on results:

Points of degradation plot (test substance):
7 % degradation after 28 d

BOD5 / COD results

Results with reference substance:

Points of degradation plot (reference substance):
91 % degradation after 14 d
101 % degradation after 28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test material did not reach 60 % within the 10-day window and after 28 days of incubation. Thus the test item is not readily biodegradable.

Executive summary:

Purpose

The test item was investigated for its ready biodegradability in a Manometric Respirometry Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. As a reference item Aniline was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.The GLP study was perfomred according to OECD TG 301F.

Result

Biodegradation of test item

After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28 -day exposure period the degradation of 7 % was found.

Biodegradation of Aniline

The reference item Aniline was sufficiently degraded to 91 % after 14 days, and to 101 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

Biodegradation in the Toxicity Control

In the toxicity control containing both, the test item and the reference item aniline, 44 % biodegradation was noted within 14 days and 52 % biodegradation was determined after 28 days of incubation. Thus, the test item can be assumed to be not inhibitory on the activated sludge micro organisms.

Conclusion

The degradation rate of the test material did not reach 60 % within the 10-day window and after 28 days of incubation. Thus the test item is not readily biodegradable.