3-Methoxy-3-methylbutyl acetate

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:

2005-02-03 to 2005-03-7

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

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” (November 21, 2003, Yakushokuhatsu No.1121002, November 13, 2003 Seikyoku No.2, Kanpokihatsu No.031121002)

Deviations:

no

GLP compliance:

yes

Remarks:

The test report cites Japanese and OECD GLP standards.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sludge was sampled from a total of ten Japanese sites; 4 sewage treatment plants, three river locations, and three lake / sea bay locations.
- Method of cultivation: Filtrate of the activated sludge was cultivated for c.a. 3 months was mixed with the filtrate of a mixture of the sludge collected from each of the 10 locations. The mixed filtrate was aerated and then the pH of the mixture was adjusted to pH 7.0 ± 1.0.
- Storage length: Sludge kept for 18 - 24 hours after the addition of synthetic water was used.
- Concentration of sludge: 3920 mg/L suspended solids.

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
- Test temperature: 25±1°C.
- pH: 7.0
- pH adjusted: pH adjustment was carried out on the inoculum, prior to addition of the test material.
- Suspended solids concentration: 30 mg/L suspended solids.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 300 mL vessels in a temperature controlled bath. Each test solution was stirred by a magnetic stirrer.
- Number of culture flasks/concentration: 3
- Measuring equipment: The change in Biochemical Oxygen Demand (BOD) of the test solution was measured and recorded using a data processing machine
- Details of trap for CO2 and volatile organics if used: Soda lime

SAMPLING
- Sampling frequency: Automatic measurement of BOD

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: No
- Toxicity control: Yes

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

(Biochemical Oxygen Demand, BOD)

Value:

90

Sampling time:

28 d

Key result

Parameter:

% degradation (DOC removal)

Value:

97

Sampling time:

28 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

100

Sampling time:

28 d

Remarks on result:

other: Determination of test substance in test solutions at the end of the biodegradation test by GC analysis.

Results with reference substance:

Aniline was found to be 67% degraded by day 7, and 71% degraded by day 14, meeting the acceptability criteria for both of these time points.

Table 1: Percentage biodegradation of the test substance

 

Vessel no.	Day 7 (%)	Day 14 (%)	Day 21 (%)	Day 28 (%)	Mean degradation (%)
1	-	-	-	-
2	20	77	87	91	90
3	21	81	88	91
4	20	29	67	88
5	-	-	-	-
6	67	71	76	79

 

Vessel no.:

(1)             Water + test substance

(2, 3, 4)    Sludge + test substance

(5)             Control blank

(6)             Sludge + aniline

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance was readily biodegraded by microorganisms under the present test conditions.

Executive summary:

A biodegradability study was conducted on the test material (3 -methoxy-3 -methybutyl acetate) to assess its degradability by sewage sludge. The study was conducted according to OECD 301C (Modified MITI Test) and in compliance with GLP. A solution of the test material was incubated over 28 days with an inoculum prepared with activated sludge derived from sewage treatment plants, rivers, lakes and marine sources. Degradation was monitored by analysis of Biochemical Oxygen Demand (BOD). The concentrations of the test material and two hydrolysis products were also determined at the end of the test by chromatographic techniques. The biodegradation of the test substance started before day 7 and on day 14 a mean biodegradation of 62% was reached. The test substance reached within 10 days a biodegradation of > 60% and was ultimately biodegraded with 90% at day 28.

Under the present test conditions the test substance is therefore considered readily biodegradable.

With this positive result the test substance can also be considered indicative of being rapidly and ultimately degraded in the environment which includes sewage treatment plants.

Description of key information

The test substance is considered readily biodegradable under the conditions of the test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

A biodegradability study was conducted on the test material (3 -methoxy-3 -methybutyl acetate) to assess its degradability by sewage sludge. The study was conducted according to OECD 301C (Modified MITI Test) and in compliance with GLP. A solution of the test material was incubated over 28 days with an inoculum prepared with activated sludge derived from sewage treatment plants, rivers, lakes and marine sources. Degradation was monitored by analysis of Biochemical Oxygen Demand (BOD). The concentrations of the test material and two hydrolysis products were also determined at the end of the test by chromatographic techniques. The biodegradation of the test substance started before day 7 and on day 14 a mean biodegradation of 62% was reached. The test substance reached within 10 days a biodegradation of > 60% and was ultimately biodegraded with 90% at day 28.

Under the present test conditions the test substance is therefore considered readily biodegradable.

With this positive result the test substance can also be considered indicative of being rapidly and ultimately degraded in the environment which includes sewage treatment plants.