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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981-10-05 till 1982-01-23
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restictions.
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
GLP compliance:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: Sludge samplings were made at 10 places in Japan. They included three city sewage plants, one industry sewage plant, three riverine areas, one lake area and two bay areas.
- Laboratory culture: About 30 minutes after ceasing the aeration to the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then the equal volume of dechlorination water was added to the remaining portion and aerated again, followed by addition of synthetic sewage, concentration of that portion was to be 0.1 (W/V) %. This procedure was repeated once every day. The incubation temperature was 25 °C ± 2 °C
- Synthetic sewage: 1 g each of glucose, peptone, and potassium dihydrogenphosphate disolved in 1 L of water and pH adjusted to 7.0 ± 1.0 with NaOH
- Method of cultivation: 5 liters of the filtrate of the supernatant of the currently-tested sample was mixed and incubated with an equal amount of a filtrate of the supernatant of a new sample
- Storage conditions: Prefiltered open air was used for aeration; the mixture was cultured at pH 7.0 ± 1.0 and 25 °C ± 2 °C.
- Concentration of sludge: 30 mg/L
- Water: purified water was used
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: 3 mL each of liquids A, B, C and D having compositions prescribed in JIS K0102-1998-21 were mixed and purified water was added up to 1 L
- Test temperature: 25 °C ± 1 °C
- pH: 7.0 ± 1.0
- pH adjusted: yes
- Aeration of dilution water: yes

TEST SYSTEM
- Measuring equipment: closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co., Ltd.)
Reference substance:
aniline
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Results with reference substance:
The biodegradation of aniline was 73 % after 28 days.
Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Activate sludge (adaptation not specified) was used as inoculum at a concentration of 30 mg/L; the concentration of 1,3-dichlorobenzene was of 100 mg/L. Ready biodegradability was measured in terms of BOD; no biodegradation was observed after four weeks (28 days) of incubation.
Executive summary:

The test was conducted according to the OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)); no deviations from the guideline were observed. Activate sludge (adaptation not specified) was used as inoculum at a concentration of 30 mg/L; the concentration of 1,3-dichlorobenzene was of 100 mg/L. Ready biodegradability was measured in terms of BOD; no biodegradation was observed after four weeks (28 days) of incubation.

Description of key information

Activate sludge (adaptation not specified) was used as inoculum at a

concentration of 30 mg/L; the concentration of 1,3-dichlorobenzene was of 100 mg/L. Ready biodegradability was measured in terms of BOD; no biodegradation was observed after four weeks (28 days) of incubation. Under anaerobic conditions, 77% primary degradation (loss of chlorine) was observed within 32 days.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information