4-Ethoxy-4'-(trans-4-ethylcyclohexyl)-2,3-difluor-1,1'-biphenyl

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:

Jun 01, 2005 - Jul 07, 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

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 (e.g. location, sampling depth, contamination history, procedure): activated sludge, micro organisms from a domestic waste water treatment plant
- Origin: Municipal sewage treatment plant
- Conditioning: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in tap water and centrifuged again. This procedure was repeated twice.
- Concentration of suspended solids per litre: 30 mg

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

According to guideline

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

28 d

Results with reference substance:

The reference item (Aniline) was sufficiently degraded to 75 % after 14 days and to 87 % after 28 days of incubation. The validity criterion that the degradation should be > 60 % after 14 d was fulfilled.

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 study according to OECD 301C over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The substance concentration during the course of this study was monitored by LC with UV detection (255 nm). As a reference item aniline was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

 

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 a degradation of 0 % as found. LC analysis confirmed that no degradation occurs.

 

Biodegradation of aniline

The reference item was sufficiently degraded to 75 % after 14 days and to 87 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

 

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.

Description of key information

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.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Purpose

The test item was investigated for its ready biodegradability in a study according to OECD 301C over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The substance concentration during the course of this study was monitored by LC with UV detection (255 nm). As a reference item aniline was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

 

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 a degradation of 0 % as found. LC analysis confirmed that no degradation occurs.

 

Biodegradation of aniline

The reference item was sufficiently degraded to 75 % after 14 days and to 87 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

 

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.