4-Butyl-4''-ethyl-2',3'-difluor-1,1':4',1''-terphenyl

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Justification for type of information:

For this endpoint information from a structural similar compound is available. This study for this similar compound was performed according to GLP and the methods applied are fully compliant with OECD 301C. See chapter 13 report for a more detailed justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Nov 17, 2008 - Feb 04, 2009

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))

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 (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 resuspended in tap water and centrifuged again. 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.

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

Preliminary study:

The biodegradation in % was calculated based on the ThOD of the test item.

Test performance:

The reference item (Aniline) was sufficiently degraded to 60, 71.4, 73.2, and 73.5 % after an incubation for 7, 14, 21 and 28 days respectively.
The validity criterion that the degradation should be > 60 % after 14d was fulfilled.

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

0

Sampling time:

28 d

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. The test material concentration was monitored by HPLC. 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 performed according to OECD TG 301C.

 

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 % was found.

 

Biodegradation of aniline

The reference item was sufficiently degraded to 75 % after 14 days and to 77 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

 

Chemical analysis

The chemical analysis confirmed the presence of the test material at 99 % throughout the experimental phase of 28 days.

 

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 information for this endpoint study record was obtained from a structural analouge in an experimental study. The OECD GLP criteria were met and the methods applied are fully compliant with OECD TG 301C. The read-across source substance was determined to be not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

No study data with the test item is available for this endpoint. Therefore, a read-across to the read-across source substance with a very similar chemical structure and comparable physico-chemical parameters is used to evaluate the endpoint for the test item.

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days via HPLC. The study was conducted according to OECD TG 301C. The test item was tested at a concentration of 100 mg/L. To check the activity of the test system aniline was used as functional control. The percentage degradation of the functional control reached the pass level of 60 % within 7 days and came to a maximum of 73.5 % on day 28. The test item replicates did not reach the 10 % level (beginning of biodegradation) within 28 days. The test item is classified as not readily biodegradable within the 28-day period of the study.