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
Study period:
November - December 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.4-F (Determination of the "Ready" Biodegradability - MITI Test)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
TEST MATERIAL
- Substance identification/name in the report: LZ 596
- Molecular formula: C21H30N2
- Batch no.: 1229
- Analysis date: August 12, 2014
- Date of production: August 11, 2014

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage conditions: Controlled room temperature (15-25ºC, <70 RH%), protected from light and humidity.
- Stability under test conditions: stable for min. 3 years from manufacturing date
- Expiry date: August 10, 2017
- Safety precautions: Routine safety precautions (lab coat, gloves, safety glasses, face mask) for unknown materials were applied to assure personnel health and safety.
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
ORIGIN:
For this type of the test the sludge sampling was made in principle, at not less than 10 places throughout the country (e.g.: from municipal sewage plants, industry sewage plant, rivers, lakes of Hungary), from areas where a variety of chemicals are used and discarded.
At the present study the sludge sampling (1.5-2 litre) was made at 10 places throughout the country (the origin, sampling conditions are documented and collected in the raw data).
About 1-1 litre samples of sludge, surface soil, water etc. from different places were mixed thoroughly together (see below).
The sampling was performed in September 2014. The different sludge samples were mixed on September 24, 2014.
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
other: BOD (Biological Oxygen Demand)
Details on study design:
PREPARATION OF SLUDGE:
The sludge samples collected from the sampling sites were mixed by stirring in a single container, and the mixture was allowed to stand. Floating foreign matter was removed and the supernatant is filtered. The prepared mixture was transferred into a culture tank and aerated.
The pH of the mixture was checked and found 6.51; therefore pH adjustment was considered as not necessary.

CULTURING:
The sludge sample was aerated for about 23.5 h. 30 minutes after the stopping of aeration one third of the whole volume of the filtered supernatant was discarded and an equal volume of the synthetic sewage, containing 0.1 % glucose, peptone and potassium orthophosphate (pH=7.0) was added to remaining portion of supernatant, and re-commence aeration. This procedure was performed once per weekday.

PREPARATION OF ACTIVATED SLUDGE INOCULUM:
On the day of the test (~24 h after the culturing unit has been fed) a representative volume of the activated sludge was decanted, and the dry weight content determined using an appropriate moisture content analyzer. The final concentration of the activated sludge inoculum in the test containers was 30 mg suspended solids.
Reference substance:
aniline
Preliminary study:
The possible toxic effect of the test item was investigated in a non GLP 14-day preliminary experiment. The test item was found to be non-toxic to the inoculum.
Key result
Parameter:
other: calculation based on BOD
Value:
0.96
Sampling time:
5 d
Key result
Parameter:
other: calculation based on BOD
Value:
3.35
Sampling time:
10 d
Key result
Parameter:
other: calculation based on BOD
Value:
3.58
Sampling time:
15 d
Key result
Parameter:
other: calculation based on BOD
Value:
4.3
Sampling time:
20 d
Key result
Parameter:
other: calculation based on BOD
Value:
4.42
Sampling time:
25 d
Key result
Parameter:
other: calculation based on BOD
Value:
4.18
Sampling time:
28 d
Details on results:
In the present experiment the oxygen uptake of the inoculum control (bottle 12) was acceptable, 45 mg/L (maximum value, measured on the 28th day of the test).
In this test the test item was investigated in three parallels. The parallels were compared with each other and the highest difference from the 14th to 28th day was 18.18 % (observed on the 14th, 15th and 16th days of the test. The pH was measured at the start and at the end of the test. At the start of the test the noticed pH range was: 6.99-7.02; at the end of the test: 7.37-8.34. The oxygen consumption (measured as biochemical oxygen demand) of the test substance was greater than the corresponding oxygen consumption value of the inoculum control, consequently higher than 60 % throughout the test. The substance concentration choice 100 mg/L was correct. The percentage degradation of aniline calculated from the oxygen consumption was 74.69 % on the 7th day and 91.29 % on the 14th day.
Key result
Parameter:
BOD5
Value:
21.6 other: mg O2/L
Remarks on result:
other: mean of three measurements
Results with reference substance:
Degradation of reference item aniline after:
- 5 days: 59.75%
- 10 days: 84.23%
- 15 days: 92.95%
- 20 days: 97.51%
- 25 days: 100%
- 28 days: 100%

The test item is considered to be not ready biodegradable. According to the test guidelines the pass level for ready biodegradability is 60 % of ThODNH4. Due to the observed zero abiotic degradation, the BOD values obtained in the test item group were not corrected with abiotic degradation values. The test item had no inhibitory effect on the applied inoculum microflora. The measured pH values remained in the acceptable 6-8.5 range throughout the test. The percentage degradation results based on the measured biochemical oxygen demand and performed chemical analysis are comparable, the obtained differences are acceptable within the variability range of the applied system. The percentage biodegradation of the reference item confirmed the suitability of the used method, system and inoculum. Biochemical oxygen demand values were measured during the experiment in the abiotic control (bottle 7) as well. Under the test conditions no abiotic degradation of this test item was noticed.

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The percentage biodegradation of the test item reached 4.18% after 28 days. The test item is considered to be not ready biodegradable. According to the test guidelines the pass level for ready biodegradability is 60 % of ThODNH4. Due to the observed zero abiotic degradation, the BOD values obtained in the test item group were not corrected with abiotic degradation values. The test item had no inhibitory effect on the applied inoculum microflora.
Executive summary:

The test item was investigated for its ready biodegradability in a MITI(I)-Test over a period of 28 days, in accordance with EC-method C.4 -F. Inoculum was activated sludge from several domestic sewage treatment plants. Aniline was used as reference substance. The percentage biodegradation of the test item reached 4.18% after 28 days based on BOD. The reference substance reached a biodegradation rate of 100% at the end of the study. The test item was not considered having significant inhibitory effects on the secondary effluent microorganisms. Based on the results of this study, the test item is considered not readily biodegradable.

Description of key information

Ready biodegradability

The test item was investigated for its ready biodegradability in a MITI(I)-Test over a period of 28 days, in accordance with EC-method C.4 -F. Inoculum was activated sludge from several domestic sewage treatment plants. Aniline was used as reference substance. The percentage biodegradation of the test item reached 4.18% after 28 days based on BOD. The reference substance reached a biodegradation rate of 100% at the end of the study. The test item was not considered to be have significant inhibitory effects on the secondary effluent microorganisms. Based on the results of this study, the test item is considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Source: GLP-report