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:
22 January 1996- 25 March 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GPL guideline study.
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes
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): City of Geneva, Aïre
- Storage conditions: aerobic
- Storage length: used on the same day as collected
- Preparation of inoculum for exposure: the sludge is collected in the morning and washed 3 times in the mineral medium by centrifuging at 1000 g for 10 min, discarding the supernatant and resuspending in mineral medium
- Concentration of sludge: 1.88 mL of sludge is needed to obtain a concentration of 30 mg/L (dry weight) in a 250 mL flask
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: Prepared by mixing 50 mL of stock solution A and 2000 mL deionised water, adding 5 mL of each of the stock solutions B, C and D and making up to 5 L with ionised water.
- Test temperature: 22 °C
- pH: 7.4 ± 0.2
- pH adjusted: Yes, with phosphoric acid or potassium hydroxide
- Suspended solids concentration: 3.985 g/L

TEST SYSTEM
- Number of culture flasks/concentration: duplicate flask per concentration
- Measuring equipment: The respirometer used during this study is a SAPROMAT D 12, made by J.M. VOITH GmbH, D-7920 Heidenheim.
- Test performed in closed vessels: yes
- Details of trap for CO2 and volatile organics if used: soda lime

SAMPLING
Everyday the oxygen consumption of each flask is recorded and correct temperature and stirring are checked. At the end of the test period, the pH of each flask is measured again.

CONTROL AND BLANK SYSTEM
A pair of flasks of the volumetric respirometer (SAPROMAT) are filled with mineral medium + test chemical (100 mg/L) + aniline (100 mg/L) + inoculums and their respirations are recorded for the other flasks. If they are lower than those of the flasks containing mineral medium + aniline (100 mg/L) + inoculums the test chemical can be assumed to be inhibitory to the inoculums used.
Reference substance:
aniline
Remarks:
minimum purity 99.5 %
Test performance:
Degradation of the reference substance exceeded 40 % over 7 days and 65 % after 14 days: the activity of the inoculums was this verified and the test was considered valid.
Parameter:
% degradation (O2 consumption)
Value:
77
Sampling time:
28 d
Details on results:
The test substance underwent 77 % biodegradability after 28 days in the test conditions. Biodegradation started on day 1 and reached 72 % at the end of the 10 day window (days 1 to 11).
Results with reference substance:
Degradation of the reference substance exceeded 40 % over 7 days and 65 % after 14 days.

Oxygen uptakes, as read on the SAPROMAT meters, were corrected by deducting the basic oxygen uptake of sludge and proportionally to account for the differences between actual and nominal concentrations of test and reference substances.

Averages of identical flasks were used to obtain the graph of BOD versus time (attachment 1), percentage of biodegradation versus time (attachment 2) and biodegradation rates.

Biodegradability of the test substance- Respirometric Method

Theoretical oxygen demand:

Formula: C6H12N0O1

Molecular weight: 100.16 g/mol

Theoretical Oxygen Demand (ThOD): 2.72 mg O2/mg

Biodegradability:

Biological Oxygen Demand (BOD, mg O2/L, adjusted to nominal concentrations):

 

 

Days:

1

7

11

14

21

28

BOD Sludge

1rst flask

B1

4.0

18.0

22.0

24.0

27.0

33.0

2ndflask

B2

1.0

17.0

20.0

22.0

25.0

31.0

mean

B

2.5

17.5

21.0

23.0

26.0

32.0

BOD Sludge Test Subst.

1rst flask

C1

41.4

181.6

223.0

238.2

247.2

247.2

2ndflask

C2

38.6

177.5

209.9

228.2

238.3

238.2

1rst fl. corr.

C1- B

38.9

164.1

202.0

215.2

221.2

215.2

2nd fl. corr.

C2- B

36.1

160.0

188.9

205.2

212.3

206.2

% degr.

1rst flask

D1

14

60

74

79

81

79

2ndflask

D2

13

59

69

75

78

79

mean

D

14

60

72

77

80

77

B= (B1 + B2)/ 2

D1= 100 * (C1 – B)/ ThOD * [S] where [S] is the initial test substance concentration (mg/L)

D2= 100 * (C2 – B)/ ThOD * [S]

D= (D1 + D2)/ 2

 

Biodegradability of the reference substance- Respirometric Method

Theoretical oxygen demand:

Formula: C6H7N1O0

Molecular weight: 93.13 g/mol

Theoretical Oxygen Demand (ThOD): 2.41 mg O2/mg

Biodegradability:

Biological Oxygen Demand (BOD, mg O2/L, adjusted to nominal concentrations):

 

 

Days:

5

7

10

14

21

28

BOD Sludge

1rst flask

B1

16.0

18.0

21.0

24.0

27.0

33.0

2ndflask

B2

14.0

17.0

19.0

22.0

25.0

31.0

mean

B

15.0

17.5

20.0

23.0

26.0

32.0

BOD Sludge Test Subst.

1rst flask

C1

184.0

199.0

209.0

215.0

220.0

229.0

2ndflask

C2

181.0

198.0

210.0

217.0

224.0

236.0

1rst fl. corr.

C1- B

169.0

181.5

189.0

192.0

194.0

197.0

2nd fl. corr.

C2- B

166.0

180.5

190.0

194.0

198.0

204.0

% degr.

1rst flask

D1

70

75

78

80

80

82

2ndflask

D2

69

75

79

80

82

85

mean

D

70

75

79

80

81

83

B= (B1 + B2)/ 2

D1= 100 * (C1 – B)/ ThOD * [S] where [S] is the initial test substance concentration (mg/L)

D2= 100 * (C2 – B)/ ThOD * [S]

D= (D1 + D2)/ 2

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The ready biodegradability of the test substance was assessed according to OECD guideline 301 F. The test substance underwent 77 % biodegradation after 28 days in the test conditions. Biodegradation started on day 1 and reached 72 % at the end of the 10-day window (days 1 to 11). Therefore, the test substance can be regarded as readily biodegradable according to this test.
Executive summary:

The ready biodegradability of the test item was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F.

The test item underwent 77 % biodegradation after 28 days in the test conditions. Biodegradation started on day 1 and reached 72 % at the end of the 10-day window (days 1 to 11).

Thus, the test item should be regarded as readily biodegradable.

At the concentration used in the test (100 mg/L), it is not inhibitory to the micro-organisms.

Description of key information

The ready biodegradability of the test substance was assessed according to OECD guideline 301 F. The test substance underwent 77 % biodegradation after 28 days in the test conditions. Biodegradation started on day 1 and reached 72 % at the end of the 10-day window (days 1 to 11). Therefore, the test substance can be regarded as readily biodegradable according to this test.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The ready biodegradability of the test item was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F. The test item underwent 77 % biodegradation after 28 days in the test conditions. Biodegradation started on day 1 and reached 72 % at the end of the 10-day window (days 1 to 11). Thus, the test item should be regarded as readily biodegradable. At the concentration used in the test (100 mg/L), it is not inhibitory to the micro-organisms.