Oxirane, 2,2'-[methylenebis[(2,6-dimethyl-4,1-phenylene)oxymethylene]]bis-

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:

29 July 1994 to 27 September 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

other: Method for Testing the Biodegradability of Chemical Substances by microorganisms stipulated in the "Testing Methods for New Chemical Substances"

Version / remarks:

July 13, 1974, Kanpogyo No.5, Planning and Coordination Bureau, Environment Agency, Yakuhatu No.615, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, and 49 Kikyoku No.392, Basic Industries Bureau, Ministry of International Trade and Industry, Japan.

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

anaerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge:
On site sludge sampling was carried out at the following 10 locations in Japan:
Fukogawa city sewage plant (Sapporo-shi Hokkaido)
Fukashiba industry sewage plant (Kashima-gun lbaragi)
Nakahama city sewage plant (Osaka-shi Osaka)
Ochiai city sewage plant (Shinjuku-ku Tokyo)
Kitakami river (Ishinomaki-shi Miyagi)
Shinano river (Nishikanbara-gun Niigata)
Yoshino river (Tokushirna-shi Tokushirna)
Lake Biwa (OISu-shi Shiga)
Hiroshima bay (Hiroshima-shi Hiroshima)
Dookai bay (Kitakyushu-shi Fukuoka)

- Sludge sampling method:
City sewage:Return sludges from sewage plants were collected.
Rivers, lakes and sea: Surface water and surface soil which are in contact with the atmosphere were collected.

- Mixing of fresh and old activated sludge: 5 L of the filtrate of the supernatant of activated sludge in use at present was mixed with each 500 mL of the filtrate of the supernatant of newly collected sludges and the mixture was cultured at pH 7.0 ± 1.0 under sufficient aeration using pre-filtered open air.

- Concentration of suspended solid in the activated sludge was 4900 mg/L.

- Laboratory culture: About 30 minutes after ceasing the aeration of the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then an equal volume of dechlorinated water was added to the remaining portion. This mixture was aerated, and then synthetic sewage was added to a concentration of 0.1(w/v) %. This procedure was repeated once every day. The culturing was carried out at 25 ± 2 °C.
- Synthetic sewage: Glucose, peplone and potassium dihydrogenphosphate respectively were dissolved in dechlorinated water. Each concentration was 5 (w/v) % and the solution was adjusted to pH 7.0 ± 1.0 with sodium hydroxide.

- Control: During the culturing, the appearance of the supernatant, setting of the sludge, formation of flock, pH, dissolved oxygen concentration in the solution and temperature were checked and necessary adjustments were made. Microflora in the activated sludge was microscopically observed and sludge with no abnormal symptoms was used for the test.

- Inspection of activity and date of initiation of use of the activated sludge: Activity of the sludge was assessed by use of a reference substance and the relation between new and old activated sludge was taken account.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Preparation of basal culture medium: Each 3 mL of solution (from the Japanese Industrial Standards) A, B, C and D, were made up to 1000 mL with purified water, and then the pH of this solution was adjusted to 7.0.
- Test temperature: 25 ± 1°C
- Suspended solids concentration: The activated sludge was added to each test vessel (b), (c) and (d), so that the concentration of suspended solid reached 30 mg/L.

TEST SYSTEM
- Culturing apparatus: 300 mL volume (improved type)
- Preparation of test solutions:
(a) Water + test material (n=1): A test vessel containing 300 mL of purified water into which 30 mg of test material was added.
(b) Sludge + test material (n=3): Each test vessel containing 300 mL of basal culture medium into which 30 mg of test material was added.
(c) Sludge + aniline (n=1): A test vessel containing 300 mL of basal culture medium into which 29.5 μL (30.0 mg) of aniline was added.
(d) Control blank (n=1): A test vessel containing 300 mL of basal culture medium into which neither the test material nor aniline was added.
- Measuring equipment: Closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co., Ltd.)
- Absorbent for carbon dioxide: Soda lime No.1
- Each test solution was stirred by a magnetic stirrer.
- After the termination of the cultivation, the test material in the test solutions were determined.

Reference substance:

aniline

Test performance:

It was concluded that the test conditions were valid.

Key result

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

28 d

Details on results:

Appearances of test solutions
- At the initiation of cultivation: Water + test material: The test material was not dissolved.
- At the initiation of cultivation: Sludge + test material: The test material was not dissolved.
- At the completion of cultivation: Water + test material: The test material had not been dissolved.
- At the completion of cultivation: Sludge + test material: The test material had not been dissolved. Changes were not observed.

Percentage biodegradation
BOD: 2% after 28 days
HPLC (Main product, peak 2): 2%
- The peaks of by-product 2 and by-product 1 were detected before and after the peak of the main product (peak 2):
HPLC (By-product 2, peak 1): 15%
HPLC (By-product 1, peak 3): 3%

Results with reference substance:

Percentage biodegradations of aniline calculated by the BOD values were 58% and 79% at the 7th and 14th day, respectively. It was concluded that the test conditions were valid.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the conditions of this study, the test material was not readily biodegradable.

Executive summary:

The ready biodegradability of the test material was investigated in a study similar to OECD 301 C, under GLP conditions.

Measurement of biochemical oxygen demand (BOD) of the test material was performed by means of a closed system with oxygen consumption measuring apparatus. Determination of the test material was performed by means of a high performance liquid chromatography (HPLC).

The average percentage biodegradation by BOD was 2%.

Under the conditions of this study, the test material was not readily biodegradable.

Description of key information

Under the conditions of the study, the test material was not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of the test material was investigated in a study similar to OECD 301 C, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Measurement of biochemical oxygen demand (BOD) of the test material was performed by means of a closed system with oxygen consumption measuring apparatus. Determination of the test material was performed by means of a high performance liquid chromatography (HPLC).

The average percentage biodegradation by BOD was 2%.

Under the conditions of this study, the test material was not readily biodegradable.