Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study, limited details on study description, statement that validity criteria are fulfilled.
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes
Remarks:
No certificate included.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No surrogate or analogue material was used.
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source: sewage treatment plant of laboratory (Wupperverband)
- Sample taking: 1992-11-11
- Pretreatment: none
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Initial conc.:
30 mg/L
Based on:
formulation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 20 +/- 1 °C
- Continuous darkness: yes
Reference substance:
aniline
Preliminary study:
No preliminary study reported.
Test performance:
Neither unusual observations during test nor any other information affecting results are reported.
Parameter:
% degradation (O2 consumption)
Value:
72
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
81
Sampling time:
28 d
Remarks on result:
other: The test substance is "readily biodegradable".
Details on results:
The Theoretical Oxygen Demand (ThOD) was determined as 2627 mgO2/g. The biodegradation of 81 % was attained already after 26 days incubation time.
Results with reference substance:
After 28 days, aniline attained 75 % degradation.

Table 1: Overview of experimental results

Day

Oxygen demand (mg/L)

Biodegradation in %

 

 

Test substance

Blind value

 

 

2

 

 

 

4

11

7

2

6

 

 

 

8

142

7

51

10

 

 

 

12

179

7

65

14

195

7

72

16

 

 

 

18

212

7

78

20

215

7

79

22

 

 

 

24

 

 

 

26

221

7

81

28

221

7

81

Figure 1: Overview of results

Please find attached.

Validity criteria fulfilled:
yes
Remarks:
Validity criteria were fulfilled.
Interpretation of results:
readily biodegradable
Conclusions:
The test material attained 81 % degradation after 28 days and is therefore considered to be "readily biodegradable". The study was conducted under GLP compliance and the study report describes all basic information.
Executive summary:

The biodegradability of the test substance was investigated in accordance to EU Method C.4-D, which corresponds in principle OECD Guideline 301 F (Kanne, 1993). The test substance (100 mg/L) was weighed into the prepared mineral medium and inoculated with activated sludge, resulting in an inoculum concentration of 30 mg TS/L. Incubation was done for 28 days at 20 +/- 1 °C under aerobic conditions. Biodegradation during this time was determined based on the measured oxygen demand, which was recorded with the help of a respirometer. The Theoretical Oxygen Demand (ThOD) is reported as 2627 mg O2/g. Neither unusual observations during test nor any other information affecting results are reported. After 28 days, the test substance attained 81 % degradation. In accordance to internationally accepted criteria of the OECD, the test substance is considered as "readily biodegradable". Aniline was used as reference substance, incubated under identical conditions and attained 75 % degradation at the end of the test.

Description of key information

Ready biodegradation experiment according to EU Method C.4-D / OECD 301F: 81 % degradation after 28 days - readily biodegradable.

Supporting information:
Calculation with BIOWIN v4.10 (EPIWIN software by US-EPA), Prediction results are not consistent. Predictions range from rapid degradation to slow degradation. Overall Ready Biodegradability Prediction: No.
"Ultimate" aerobic biodegradation test according to ISO 7827: 68 % degradation - not persistent.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

Screening data concerning biodegradation in water are available as experimental study results as well as QSAR predictions. The biodegradability of the test substance was investigated in accordance to EU Method C.4-D, which corresponds in principle OECD Guideline 301 F (Kanne, 1993). The test substance (100 mg/L) was weighed into the prepared mineral medium and inoculated with activated sludge, resulting in an inoculum concentration of 30 mg TS/L. Incubation was done for 28 days at 20 +/- 1 °C under aerobic conditions. Biodegradation during this time was determined based on the measured oxygen demand, which was recorded with the help of a respirometer. The Theoretical Oxygen Demand (ThOD) is reported as 2627 mgO2/g. After 28 days, the test substance attained 81 % degradation. In accordance to internationally accepted criteria of the OECD, the test substance is "readily biodegradable". Aniline was used as reference substance, incubated under identical conditions and attained 75 % degradation at the end of the test.

Furthermore, the potential for biodegradation in water of the test substance was predicted with the computer program BIOWIN v4.10 (EPIWIN v4.1) of US-EPA. The program calculates with seven different models: Linear Model (Biowin 1), Non-linear Model (Biowin 2), Ultimate Biodegradation Timeframe (Biowin 3), Primary Biodegradation Timeframe (Biowin 4), MITI Linear Model (Biowin 5), MITI Non-linear Model (Biowin 6) and Anaerobic Model (Biowin 7). The overall result describes the ready biodegradability prediction of the compound.

According to the Linear Model as well as the Non-Linear Model, the substance is biodegrading fast. The Ultimate Biodegradation Timeframe is "weeks", and the Primary Biodegradation Timeframe reveals "days-weeks" for 4-phenylbutenone. Both MITI Models predict that the substance is not readily biodegradable, which is also the prediction as overall result. Also under anaerobic conditions the substance is suspected to be not biodegraded fast.

The Ultimate and Primary Timeframe indicate that 4-phenylbutenone is not persistent in the environment. This is supported by an available publication which reports about the investigation of environmental impact of wastewater form a chemical-pharmaceutical plant (Brorson et al., 1994). In this context, the test substance was investigated according to the "ultimate" aerobic biodegradability test ISO 7827. After an exposure time of 28 days, 4-phenylputenone attained 68 % degradation, however, it is also reported that the study leaves some uncertainty about this result since a carrier of bentonite was applied.

As conclusion, 4-phenylbutenone is considered as "readily biodegradable" and therefore also as "not persistent" in the environment.