[No public or meaningful name is available]

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:

2019-12-20 - 2020-02-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Also according to GLP.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

July 17 1992

Deviations:

no

GLP compliance:

yes

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): sludge sampling was carried out at 10 locations (surface water and surface soil of rivers, lake, and inland sea, and return sludge from sewage plants). Sampled Nov 2019.
- Method of cultivation: Activated sludge was cultivated for 19.3h after feeding with the synthetic sewage.
- Storage length: 1 month
- Preparation of inoculum for exposure: amount of activate sludge was added to culture medium
- Concentration of sludge: 30 mg/L (as concentration of suspended solid)

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:

TEST CONDITIONS
- Composition of medium: Based on the guideline
- Solubilising agent (type and concentration if used): not applicable
- Test temperature: 25 °C
- pH: 7.1-7.2
- pH adjusted: yes
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Glass vessel
- Number of culture flasks/concentration: 3 for the test item with sludge, 1 for the test item and water, 1 control
- Measuring equipment: closed system oxygen consumption measuring apparatus/GC
- Test performed in closed vessels due to significant volatility of test substance: no

SAMPLING
- Sampling frequency: Weekly
- Sampling method: Closed measurement analysis

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

Reference substance:

aniline

Test performance:

No adverse effects on the reliability of this test were noted.

Parameter:

% degradation (O2 consumption)

Value:

-3

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

28 d

Details on results:

Undissolved material observed in the test item vessels.

Results with reference substance:

70% at Day 7
90% at Day 14

Validity criteria:

- Difference between extremes of replicates of the test solutions: 1%

- Percentage degradation with the reference substance: 70% at day 7 and 90% at day 14

- BOD in control: 25 mg/L

 

Table. Percentage biodegradation by BOD

		Day 7		Day 14		Day 21		Day 28		Average
		BOD	Deg (%)	BOD	Deg (%)	BOD	Deg (%)	BOD	Deg (%)	Deg (%)
Water + test item		0	-	0	-	0.3	-	0.5	-	-
Sludge + test item	1	1.9	0	3.5	-2	4.5	-2	5.1	-3	-3
	2	2.1	0	3.8	-2	4.8	-2	5.5	-2
	3	2.1	0	3.7	-2	4.6	-2	5	-3
Control		1.8	-	5.4	-	6.7	-	7.6	-	-
Reference substance		52.6	70	70.8	90	75.1	95	77.1	96	-

Table. Percentage degradation by test item analysis at Day 28.

		Amount test item (mg)	Percentage residual	Percentage degradation
Water + test item		29.1	97
Sludge + test item	1	28.9	96	1
	2	28.7	96	2
	3	28.6	95	2

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item did not undergo biodegradation under the test conditions of this study.

Executive summary:

The biodegradability of the test item was investigated in an OECD TG 301C test which complied with GLP. A concentration of 100 mg/L of test item was used and incubated with 30 mg/L of activated sludge for 28 days at ca. 25 °C. The biodegradation of the test item was followed through measurement of the biochemical oxygen demand in order to determine oxygen consumption and through direct analysis of the test item by gas chromatography.

The average biodegradation of the test item measured through oxygen consumption was -3%.

The average biodegradation of the test item measured through GC analysis was 1%.

Therefore, it is concluded that the test item did not undergo biodegradation under the test conditions of this study.

Description of key information

The test item did not undergo biodegradation in an OECD 301C test.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The biodegradability of the test item was investigated in an OECD TG 301C test which complied with GLP. A concentration of 100 mg/L of test item was used and incubated with 30 mg/L of activated sludge for 28 days at ca. 25 °C. The biodegradation of the test item was followed through measurement of the biochemical oxygen demand in order to determine oxygen consumption and through direct analysis of the test item by gas chromatography.

The average biodegradation of the test item measured through oxygen consumption was -3%.

The average biodegradation of the test item measured through GC analysis was 1%.

Therefore, it is concluded that the test item did not undergo biodegradation under the test conditions of this study.