Anisole

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Although GLP were not mentioned, validity criteria and details on result were not available, the study was performed according the OECD test guideline and was generated by the Japanese Competent Authorities.

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

Preparation of activated sludge: A mix of old and fresh activated sludge is performed every three months. Fresh activated sludge is a mixture of ten samples from different cities and industrial sewage plants, soils and rivers in Japan. This mixture was then cultured at pH=7+/-1 under aeration
Concentration: 30 mg/L
No other information on the inoculum available.

Duration of test (contact time):

2 wk

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: BOD

Details on study design:

TEST CONDITIONS: no data
TEST SYSTEM
- Volume of test solution: 300 mL
- Number of culture flasks/concentration: 3
- magnetic stirrer
- Test temperature: 25°C +/- 1°C
- Culture medium: according to Japanese Industrial Standards JIS K 0102-1986-21 adjusted to pH = 7
No other data

SAMPLING: No data

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1 test vessel with 300mL of basal culture medium (sludge)
- water + test substance at 100 mg/L
- reference substance: sludge + aniline at 100 mg/L

STATISTICAL METHODS: no data

Reference substance:

aniline

Parameter:

other: BOD

Value:

56

Sampling time:

2 wk

Results with reference substance:

With aniline, percentages of biodegradation calculated by BOD value were beyond 40% and 60% after 7 and 14 days respectively.

In a 2-week biodegradation screening test (MITI test) of Anisole (100 mg/L) using an activated sludge inoculum, 56% of BOD was removed. At the end of the 2-week period there was an upward trend in BOD consumption.

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Although the biodegradation observed does not strictly enable to conclude on the ready biodegradability profile of the substance, because the biodegradation is below the pass level of 60% and no measurements are available between 14 and 28 days, it is however possible to conclude that the substance is readily biodegradable base on the following two aspects:
- the biodegradation observed at 14d is very closed to the pass level for ready biodegradability at 28d. Therefore, it is anticipated that this pass level would have been fulfilled
- the 10 -d window does not apply to the MITI method.

Description of key information

Anisole has been demonstrated to be readily biodegradable in screening test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A reliable key study is available for ready biodegradability. During 14 days, the biodegradation of anisole at an initial concentration of 100 mg/L was studied according to OECD guideline 301C.

Inoculum used in the test was an activated sludge at a concentration of 30 mg/L obtained by mixing 10 different samples from different city and industrial sewage plants, soils and rivers in Japan.

The percentage of biodegradation was estimated by the Biological Oxygen Demand (BOD).

The corresponding percentage of biodegradation obtained after 14 days was 56%.

Although this value does not strictly enable to conclude on the ready biodegradability profile of the substance, because the biodegradation is below the pass level of 60% and no measurements are available between 14 and 28 days, it is however possible to conclude that the substance is readily biodegradable base on the following two aspects:

- the biodegradation observed at 14d is very closed to the pass level for ready biodegradability at 28d. Therefore, it is anticipated that this pass level would have been fulfilled

- the 10 -d window does not apply to the MITI method.

In conclusion, under the test conditions anisole is readily biodegradable.

Although GLP were not mentioned, validity criteria and details on results were not available, this study was performed according to OECD test guideline and was generated by the Japanese Competent Authorities. This study is therefore considered as reliable with acceptable restriction.

Three additionnal data of unknown validity support this conclusion.