Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 Feb - 19 Mar 2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
1992
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
Version / remarks:
Paragraph (q)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of the United Kingdom

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum: A mixed population of sewage treatmentmicro-organisms was obtained on 18 February 2019 from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, UK, which treats predominantly domestic sewage.
- Preparation of inoculum for exposure: The sample of effluent was filtered through coarse filter paper (first approximate 200 mL discarded) and maintained on aeration in a temperature controlled room at approximately 20 °C prior to use. The deionized reverse osmosis water used for the preparation of the mineral medium and the mineral medium used for the test contained less than 1 mg/L Total Organic Carbon.
- Initial inoculum rate in vessel: Inoculum rate of 1% v/v
- Water filtered: yes
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium (composition recommended by OECD guideline 301)
- Test item preparation: Due to the volatile nature of the test item, the test item was added directly to the test vessels. An aliquot of mineral medium (495 mL) was dispensed into each test vessel. An aliquot of inoculum (5 mL) was added prior to an amount of test item (70 µL, equivalent to 50 mg of test item determined by preliminary weighings) being dispensed into the inoculated mineral medium to give the test concentration of 100 mg/L.
- Test temperature: 19 - 21°C
- pH: 6.0 - 8.5
- pH adjusted: no
- Aeration of dilution water: yes
- Continuous darkness: no, diffuse light

TEST SYSTEM
- Culturing apparatus: 500 mL bottles
- Number of culture flasks: 3 replicates (mineral medium and the test item at a concentration of 100 mg/L)
- Method used to create aerobic conditions: Prior to the start of the test, the purified water was aerated for approximately 20 hours at the test temperature to give a dissolved oxygen concentration of approximately 9 mg O2/L.
- Measuring equipment: Hach HQ40d Flexi handheld meter (pH measurement), CES Multi-Channel Aerobic Respirometer
- Test performed in closed vessels due to significant volatility of test substance: yes
- Test performed in open system: no
- Details of trap for CO2: flask were sealed by a sensor head/CO2 trap.
- Conditions: The samples were stirred for the duration of the test with a magnetically coupled stirrer. Flaks were immersed in a temperature controlled water bath.

SAMPLING
- Sampling frequency: Biological Oxygen Demand: daily (inoculum control, test item, procedure control and the toxicity control), temperature: daily (water bath), pH: day 0 (in all test vessels before addition of the inoculum and then if applicable the test item), day 28 (two inoculum controls, one procedure control, two test item and one toxicity control vessel)

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 replicates (inoculated mineral medium to act as the inoculum control)
- Procedure control: 2 replicates (inoculated mineral medium and the reference item, aniline, at a concentration of 100 mg/L)
- Toxicity control: 2 replicates (the test item at a concentration of 100 mg/L in inoculated mineral medium plus reference item, aniline, at a concentration of 100 mg/L
Reference substance
Reference substance:
aniline
Remarks:
100 m/L

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
10
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
Aniline (procedure control) attained 69% biodegradation after 14 days in a 10-Day Window and 73% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Any other information on results incl. tables

Table 1: Biological Oxygen Demand (BOD) Values.

 

 

Day

BOD (mg O2/L)

Inoculum Control

Procedure Control

Test Item

Toxicity Control

R1

R2

R1

R2

0

0.00

0.00

0.00

0.00

0.00

0.00

1

0.24

0.16

0.24

6.12

6.24

6.16

2

0.66

0.50

0.92

11.00

10.66

10.46

3

0.66

0.96

2.74

15.08

13.86

14.42

4

1.00

1.80

12.38

18.08

16.42

22.44

5

1.24

2.58

67.44

20.20

18.32

80.00

6

2.16

3.70

138.24

22.50

20.46

150.48

7

2.88

4.54

176.30

24.16

22.00

182.56

8

3.38

5.28

187.84

25.62

23.36

188.68

9

3.84

5.96

196.54

26.78

24.54

192.22

10

4.24

6.16

204.96

27.40

25.08

195.22

11

4.70

7.08

210.46

28.70

26.36

199.42

12

5.42

7.96

213.92

29.86

27.70

203.92

13

6.46

9.08

217.42

31.32

29.20

208.08

14

7.28

10.00

220.66

32.44

30.36

211.08

15

8.08

10.66

223.86

33.16

31.12

213.16

16

8.46

11.32

227.82

34.36

32.32

215.92

17

9.08

12.04

230.40

35.40

33.40

218.00

18

9.74

12.70

232.20

36.28

34.28

219.92

19

10.16

13.46

234.04

37.52

35.48

222.20

20

10.78

14.16

235.40

38.56

36.44

224.66

21

11.38

14.66

236.16

39.06

36.98

228.32

22

11.92

15.28

237.12

39.82

37.70

234.12

23

11.92

15.28

237.86

40.16

38.02

240.28

24

11.92

15.78

238.98

41.10

39.02

244.70

25

12.90

16.32

239.94

41.94

39.86

248.48

26

14.20

16.82

240.82

42.74

40.60

252.20

27

15.20

17.46

241.82

43.60

41.52

255.86

28

15.94

17.96

242.40

44.20

42.10

258.24

R = replicate

Table 2: Percentage biodegradation values.

 

 

 

Day

Biodegradation (%)

Procedure Control

Test Item

ToxicityControl

R1

R2

Mean

0

0

0

0

0

0

1

0

2

2

2

1

2

0

4

4

4

2

3

1

5

5

5

2

4

4

6

6

6

4

5

21

7

6

7

14

6

44

7

7

7

26

7

56

8

7

8

31

8

59

8

7

8

32

9

62

8

7

8

33

10

65

8

7

8

33

11

66

9

8

9

34

12

67

9

8

9

34

13

68

9

8

9

35

14

69

9

8

9

35

15

69

9

8

9

35

16

71

9

8

9

36

17

71

9

9

9

36

18

72

9

9

9

36

19

72

10

9

10

37

20

72

10

9

10

37

21

72

10

9

10

37

22

72

10

9

10

38

23

73

10

9

10

39

24

73

10

9

10

40

25

73

10

9

10

41

26

73

10

9

10

41

27

73

10

9

10

42

28

73

10

9

10

42

R = replicate

Table 3: Validity criteria for OECD 301.

Criterion from the guideline

Outcome

Validity criterion fulfilled

Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.

 Difference between extremes of replicate BOD values at the end of the test: < 20%

 yes

Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).

 69% by day 14

 yes

The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.

5% biodegradation after 14 days and 42% biodegradation biodegradation after
28 days

 yes

The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.

 16.95 mg O2/L

yes 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
For further details please refer to “Any other information on results incl. tables”.
Interpretation of results:
not readily biodegradable