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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
mixture of sewage, soil and natural water
Details on inoculum:
On-site sludge sampling was carried out at the following 10 locations in Japan:
Fushikogawa city sewage plant (Sapporo-shi, Hokkaido)
Fukashiba industrial sewage plant (Kamishu-shi, Ibaraki)
Nakahama sewage treatment plant (Osaka-shi, Osaka)
Ochiai city treatment plant (Shinjuku-ku, Tokyo)
Kitakami River (Ishinomaki-shi, Miyagi)
Shinano River (Niigata-shi, Niigata)
Yoshino River (Tokushima-shi, Tokushima)
Lake Biwa (Otsu-shi, Shiga)
Hiroshima Bay (Hiroshima-shi, Hiroshima)
Dokai Bay (Kitakyushu-shi, Fukuoka)

From the sewage plants, the return sludges were collected and from rivers, lake and marine sites surface water and surface soil was collected.

Activated sludge was prepared as follows:
The filtrate (5 L) of the supernatant of the activated sludge cultivated for about 3 months was mixed with the mixed filtrate (5 L) of the supernatant of a sludge collected newly at each location. The mixed filtrate (10 L) was aerated after the pH value of the mixture was adjusted to ca. 7.0.
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: basal culture medium
- Test temperature: 25 ± 1 ºC
- pH: 7.0
- pH adjusted: yes
- Aeration of dilution water: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 300 mL vessels
- Number of culture flasks/concentration: 3
- Measuring equipment: closed system oxygen consumption measuring apparatus (temperature controlled bath and measuring unit including data sampler)
- Details of trap for CO2 and volatile organics if used: soda lime

SAMPLING
- Sampling method: data sampler

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 replicates
- Abiotic sterile control: yes, 1 replicate
- Toxicity control: no
- Other: positive control (aniline), 3 replicates
Reference substance:
aniline
Key result
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Details on results:
After 28 days the BOD of AC-6000 ranged from 10.4 to 12.2 mg, the degradation ranged from -12 to -5%, the average degradation was -9% (measured as O2-consumption), therefore the degradation was assumed to be 0%.
Results with reference substance:
The BOD was 76.1 mg, after 28 days 69% of the aniline was degraded (measured as O2-consumption)
Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item was not biodegraded by microorganisms under the test conditions of this study.
Executive summary:

The biodegradation of AC-6000 by microorganisms was studied in accordance with OECD guideline 301C (Modified MITI test (I)). In this GLP-compliant study 30 mg/L activated sludge (prepared from samples taken from industrial and city sewage treatment plants, surface water and surface soil) was exposed to 100 mg/L AC-6000 for 28 days in triplicate. The controls included an inoculum blank (3 replicates), an abiotic sterile control (1 replicate) and a positive control (aniline, 3 replicates). After 7, 14, 21 and 28 days the removal of oxygen expressed as biochemical oxygen demand (BOD) were calculated. In addition, the concentrations of test substance were analysed with high performance liquid chromatography (HPLC). After 28 days the BOD of AC-6000 ranged from 10.4 to 12.2 mg, the degradation ranged from -12 to -5%, the average degradation was -9% (measured as O2-consumption), therefore the degradation was assumed to be 0%. The degradation of the reference substance was 69% (measured as O2-consumption) after 28 days. AC-6000 was not biodegraded by microorganisms under the test conditions of this study.

Description of key information

The biodegradation of AC-6000 by microorganisms was studied in accordance with OECD guideline 301C (Modified MITI test (I)). In this GLP-compliant study 30 mg/L activated sludge (prepared from samples taken from industrial and city sewage treatment plants, surface water and surface soil) was exposed to 100 mg/L AC-6000 for 28 days in triplicate. The controls included an inoculum blank (3 replicates), an abiotic sterile control (1 replicate) and a positive control (aniline, 3 replicates). After 7, 14, 21 and 28 days the removal of oxygen expressed as biochemical oxygen demand (BOD) were calculated. In addition, the concentrations of test substance were analysed with high performance liquid chromatography (HPLC). After 28 days the BOD of AC-6000 ranged from 10.4 to 12.2 mg, the degradation ranged from -12 to -5%, the average degradation was -9% (measured as O2-consumption), therefore the degradation was assumed to be 0%. The degradation of the reference substance was 69% (measured as O2-consumption) after 28 days. AC-6000 was not biodegraded by microorganisms under the test conditions of this study.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The biodegradation of AC-6000 by microorganisms was studied in accordance with OECD guideline 301C (Modified MITI test (I)) (Kurume Laboratory, 2006a).

In this GLP-compliant study 30 mg/L activated sludge (prepared from samples taken from industrial and city sewage treatment plants, surface water and surface soil) was exposed to 100 mg/L AC-6000 for 28 days in triplicate. The controls included an inoculum blank (3 replicates), an abiotic sterile control (1 replicate) and a positive control (aniline, 3 replicates). After 7, 14, 21 and 28 days the removal of oxygen expressed as biochemical oxygen demand (BOD) were calculated. In addition, the concentrations of test substance were analysed with high performance liquid chromatography (HPLC). After 28 days the BOD of AC-6000 ranged from 10.4 to 12.2 mg, the degradation ranged from -12 to -5%, the average degradation was -9% (measured as O2-consumption), therefore the degradation was assumed to be 0%. The degradation of the reference substance was 69% (measured as O2-consumption) after 28 days. AC-6000 was not biodegraded by microorganisms under the test conditions of this study.