Reaction mass of methyl acetate and methanol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: Standard Methods for the Examination of Water and Wastewater. 1971. 13th Ed. American Public Health Association, New York, NY

Principles of method if other than guideline:

closed bottle test (BOD of THOD)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): domestic wastewater
- Preparation of inoculum for exposure: Settled domestic wastewater was filtered through glass wool and then added (3 mL/bottle) as seed material to clean 300 mL BOD bottles. The bottles were half filled with aerated dilution water containing specified minerals along with buffer.

Duration of test (contact time):

20 d

Initial conc.:

3 mg/L

Based on:

test mat.

Initial conc.:

7 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Aeration of dilution water: aerated dilution water used at beginning of test; reaeration when DO of test flasks dropped below 4.0 mg/L

TEST SYSTEM
- Method used to create aerobic conditions: A clean, empty BOD bottle and the test bottle were connected with an adapter; by allowing half of the liquid to pass into the new bottle, followed by moderate shaking, the DO level could be returned to about 7 mg/L. Once this reaeration was accomplished, all of the liquid was returned to the original bottle, and a new DO value was determined.
- Measuring equipment: commercial DO meter
- Test performed in closed vessels due to significant volatility of test substance: yes; flask were only opened in order to reaerate samples

SAMPLING
- Sampling frequency: five times during the 20 day test period

Reference substance:

not specified

Parameter:

% degradation (O2 consumption)

Value:

76

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

88

Sampling time:

10 d

Parameter:

% degradation (O2 consumption)

Value:

91

Sampling time:

15 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

95

Sampling time:

20 d

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: Standard Methods for the Examination of Water and Wastewater. 1971. 13th Ed. American Public Health Association, New York, NY

Principles of method if other than guideline:

closed bottle test (BOD of THOD)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: marine water, raw wastewater, bacteria, growth factors

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):seawater taken from Lavaca Bay, Texas, USA
- Preparation of inoculum for exposure: Seawater seed source was maintained by adding small amounts of settled raw wastewater about every 3 to 4 days as a source of substrate, seed bacteria, and growth factors.

Duration of test (contact time):

20 d

Initial conc.:

3 mg/L

Based on:

test mat.

Initial conc.:

7 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Aeration of dilution water: aerated dilution water used at beginning of test; reaeration when DO of test flasks dropped below 4.0 mg/L

TEST SYSTEM
- Method used to create aerobic conditions: A clean, empty BOD bottle and the test bottle were connected with an adapter; by allowing half of the liquid to pass into the new bottle, followed by moderate shaking, the DO level could be returned to about 7 mg/L. Once this reaeration was accomplished, all of the liquid was returned to the original bottle, and a new DO value was determined.
- Measuring equipment: commercial DO meter
- Test performed in closed vessels due to significant volatility of test substance: yes; flask were only opened in order to reaerate samples

SAMPLING
- Sampling frequency: five times during the 20 day test period

Reference substance:

not specified

Parameter:

% degradation (O2 consumption)

Value:

69

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

84

Sampling time:

10 d

Parameter:

% degradation (O2 consumption)

Value:

85

Sampling time:

15 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

97

Sampling time:

20 d

Interpretation of results:

readily biodegradable

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Respirometric test (BOD of THOD). Determination of the reaction kinetic by means of the respirometric dilution method. This method involves the use of a nutritious matrix, usually but not necessarily domestic sewage, which contains a lot of organic substances competing as nutrient with the substrate under test.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

Sewage water from a domestic sewage treatment plant in Stuttgart, Germany was sieved and if necessary diluted with tap water to reach a consumption of potassium permanganate of 250 - 300 mg/L

Duration of test (contact time):

8 - 10 d

Initial conc.:

4 - 200 g/L

Based on:

other: test material along with Urea and Di-sodiumhydrogenphosphat-12-hydrate

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

not specified

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

BOD/ThOD

Value:

82.7

Sampling time:

5 d

Details on results:

ThOD: 1498 mg/g
rate constant K: 1.882 1/d
L/ThOD at day 5: 82.5%

Key result

Parameter:

BOD5

Value:

1 236 mg O2/g test mat.

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

The test item was found to be readily biodgradabale after (82.7% after 5 days based on BOD/ThOD).

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Respirometric test (BOD of THOD). Determination of the reaction kinetic by means of the respirometric dilution method. This method involves the use of a nutritious matrix, usually but not necessarily domestic sewage, which contains a lot of organic substances competing as nutrient with the substrate under test.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: other bacteria: synthetic sewage

Details on inoculum:

- Preparation of inoculum for exposure:
synthetic waste water: the following components were diluted in 1L tap water: 156.3 mg Peptone from Casein, 104.2 meat extract, 27.1 mg Urea, 7.8 mg Penta-sodiumtriphosphate, 4.2 mg Calciumchloride, 2.1 mg Magnesium sulphate, 6.2 mg Sodiumchloride.
1L of sieved and adapted water from a domestic sewage treatment plant in Stuttgart, Germany was centrifuged for 30 min. After decantation the residuum was diluted again in 100 mL tap water, shaken and centrifuged. The resulting sediment was then diluted in 1L of the synthetic wastewater. After stirring for 3 - 4 hours the mixture was used for the preparation of the dilution series.

Duration of test (contact time):

8 - 10 d

Initial conc.:

4 - 200 g/L

Based on:

other: test material along with Urea and Di-sodiumhydrogenphosphat-12-hydrate

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

not specified

Preliminary study:

no data

Key result

Parameter:

other: BOD/ThOD

Value:

71.5

Sampling time:

5 d

Details on results:

ThOD: 1498 mg/g
rate constant K: 1.397 1/d
L/ThOD at day 5: 71.2%

Key result

Parameter:

BOD5

Value:

1 067 mg O2/g test mat.

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Reference 5

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

97

Sampling time:

20 d

Interpretation of results:

readily biodegradable

Reference 6

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (DOC removal)

Value:

30

Sampling time:

3 h

Conclusions:

In a Zahln-Wellens test the test item was degradated ca. 30 % after 3 h (36 % or 44 %, resp.) refered to DOC and >95 % after 6 d.

Reference 7

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

BOD

Value:

92

Sampling time:

14 d

Interpretation of results:

readily biodegradable

Reference 8

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Interpretation of results:

readily biodegradable

Reference 9

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

95

Sampling time:

20 d

Interpretation of results:

readily biodegradable

Reference 10

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

BOD/ThOD

Value:

82.7

Sampling time:

5 d

Interpretation of results:

readily biodegradable

Reference 11

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

BOD/DOC

Value:

71.5

Sampling time:

5 d

Interpretation of results:

readily biodegradable

Reference 12

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

study by reputated testing insitute according to common laboratory guidelines

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Principles of method if other than guideline:

not specified

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Key result

Parameter:

% degradation (DOC removal)

Value:

30

Sampling time:

3 h

Conclusions:

In a Zahln-Wellens test the test item was degradated ca. 30 % after 3 h (36 % or 44 %, resp.) refered to DOC and >95 % after 6 d.

Executive summary:

To assess the biodegradability of the test item a Zahn-Wellens test was performed without controls. The elimination was presumably by stripping to some extent. As a result, the test item was eliminated 30 % after 3 h (36 % or 44 %, resp.) based on DOC. An eliminiation of >95 % was detected after after 6 d. The quota of abiotic elimination is not quantifiable.

Reference 13

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

study published by a recognized Japanese authority

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:

other: see "Details on inoculum"

Details on inoculum:

- Source of inoculum/activated sludge: Ten sampling sites for domestic and industrial sludge as well as rivers are stated in the report, because the document deal with more then one test on biodegradability. It is assumed that non-adapted domestic sludge was used, because test on ready (and not inherent) biodegradability was conducted.
- Laboratory culture: The filtrate of the supernatant of an activated sludge in present use was mixed with the filtrate of the supernatant of a newly collected sludge. The mixture was cultured at pH 7.0 +/- 1.0 under sufficient aeration. About 30 minutes after stopping the aeration, about 1/3 of the volume of the supenatant was removed. An equal volume of dechlorinated water was added and aerated again and synthetic sewage was added at an amount of 0.1 % (w/v). This procedure was repeated every day. The culturing was out at 25° +/- 2°C.

Duration of test (contact time):

14 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 medium according to JIS 102-1986-14.1
- Test temperature: 25 +/- 1°C
- pH: pH of the basal culture medium was adjusted to 7.0. During the test, pH of each test solution was measured, but detailes are not specified.
- pH adjusted: yes (basal culture medium)
- Suspended solids concentration: 30 mg/L


TEST SYSTEM
- Culturing apparatus: 300 ml test vessels
- Measuring equipment: Closed system oxygen consumption measuring apparatus (Ohkura Electric Co., Ltd)
- Test performed in closed vessels due to significant volatility of test substance: Yes. It is stated in the report that an "improved type for a volatile substance" was used
- Details of trap for CO2 and volatile organics if used: Soda lime was used for the absorption of carbon dioxide
- Other: Test solution was stirred by a magnetic stirrer.


CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (basal culture medium only)
- Abiotic sterile control: Yes (purified water and test substance)
- Toxicity control: No

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

BOD

Value:

92

Sampling time:

14 d

Remarks on result:

other: Indirect analysis

Parameter:

% degradation (TOC removal)

Value:

96

Sampling time:

14 d

Remarks on result:

other: Direct analysis

Parameter:

% degradation (test mat. analysis)

Value:

100

Sampling time:

14 d

Remarks on result:

other: Direct analysis (GC determination)

Results with reference substance:

not stated

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Executive summary:

The ready biodegradability of methyl acetate was evaluated in a modified MITI test according to OECD 301 C over a period of 14 days. A solution of 100 ppm test substance was inoculated with activated sludge. Aniline was used as the reference substance. BOD, TOC as well as a gaschromatographical determination of the test substance at the end of the test period served as parameters for degradation. At the end of the test period, all endpoint were beyond at least 92%, indicating a ready biodegradability of the test substance.

Reference 14

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

24.11.1994 - 22.12.1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Qualifier:

according to guideline

Guideline:

other: ISO DIS 10707 (1994)

GLP compliance:

yes

Remarks:

Data owner has QAU statement

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Effluent of the STP of the city of Frankfurt/Main, Frankfurt-Sindlingen
- Preparation of inoculum for exposure: filtration
- Pretreatment: aeration for three days for the depletion of BOD
- Concentration of sludge: 0.5 ml/l
- Type and size of filter used, if any: folded filter. No more details given

Duration of test (contact time):

28 d

Initial conc.:

3.6 mg/L

Based on:

test mat.

Initial conc.:

5.44 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 20°C +/- 1°C
- pH: 7.37 (stock solution)
- pH adjusted: yes, the pH of the stock solution was adjusted with NaOH from 6.98 to 7.37
- Test performed in closed vessels due to significant volatility of test substance: yes (closed bottle test according to guideline)
- Test performed in open system: no

TEST SYSTEM
- Culturing apparatus: 250 ml BOD flasks
- Number of culture flasks/concentration: 3

SAMPLING
- Sampling frequency: on day 0, 7, 14, 19 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: no

Reference substance:

other: sodium benzoate

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

0 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

52

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

74

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

75

Sampling time:

19 d

Details on results:

After a lag phase of two days, the degradation of methyl acetate based on oxygen consumption reached > 68% within 10 days. Within the test period of 28 days, the degradation of methyl acetate reached 70%. The oxygen consuption based on endogenic respiration of the bacteria was determined in the inoculum blank and remained below 1 mg/L O2

Results with reference substance:

The degradation rate of the reference substance sodium benzoate was > 60% of its theoretical maximum within 14 days.

Table 1: Mean degradation rates of methyl acetate and the reference substance sodium benzoate based on oxygen consumption 

	Degradation rate [%]
Day	Methyl acetate	Sodium benzoate
0	1	0
7	52	66
14	74	88
19	75	94
28	70	71

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

After a lag-phase of two days, degradation of methyl acetate reached > 68 % within the ten-day window and 70 % within the complete test duration of 28 days. The reference substance sodium benzoate reached a degradation of 88 % within 14 days, indicating the suitability of the test system. Based on the results, mehtyl acetate can be classified as "ready biodegradabel, reaching the ten-day window".

Executive summary:

The ready biodegradability of methyl acetate was tested in a closed bottle test accoding to OECD 301 D over a period of 28 days. Sodium benzoate served as the reference substance. The mean degradation rate of methyl acetate based on oxygen was > 68% within the 10-day window and reached 70% at the end of the test period. Methyl acetate is therefore considered to be ready biodegradable reaching the 10-days window.

Description of key information

Based on a read across to the source substances Methanol and Methyl acetate the registration substance is considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

No data on the biodegradability of the target substance are available. Therefore, a read across with structural analogues Methanol and Methyl acetate was applied. The available information was assessed in a weight of evidence approach.

Methanol

Methanol is readily biodegradable in freshwater based on the results of standard ready biodegradability tests that show 71.5 – 95 percent removal after 5 and 20 days, respectively (Price et al. 1974; Wagner 1976). In marine water degradation rates were found between 69 - 97 % (Price et al. 1974).

Methyl acetate

The ready biodegradability of methyl acetate was tested in a closed bottle test according to OECD 301 D over a period of 28 days. Sodium benzoate served as the reference substance. The mean degradation rate of methyl acetate based on oxygen was > 68% within the 10-day window and reached 70% at the end of the test period. Methyl acetate is therefore considered to be ready biodegradable reaching the 10-days window.

The ready biodegradability of methyl acetate was evaluated in a modified MITI test according to OECD 301 C over a period of 14 days by the National Institute of Technology and Evaluation, Japan (1993). A solution of 100 ppm test substance was inoculated with activated sludge. Aniline was used as the reference substance. BOD, TOC as well as a gaschromatographical determination of the test substance at the end of the test period served as parameters for degradation. At the end of the test period, all endpoints were beyond at least 92%, indicating a ready biodegradability of the test substance.

In a Zahn-Wellens test methyl acetate was assessed for biodegradability without control system. The elimination was presumably by stripping to some extent. As a result, the test item was eliminated 30 % after 3 h (36 % or 44 %, resp.) based on DOC. An eliminiation of >95 % was detected after after 6 d. The quota of abiotic elimination is not quantifiable (Hoechst, 1985). The study is considered not assignable (Klimisch 4) because of insufficient documentation and is not further considered for assessment.

Conclusion

Methanol was found to be readily degradable under both aerobic and anaerobic conditions in a wide variety of environmental media including fresh and salt water, sediments and soils, ground water, aquifer material and industrial wastewater. These findings are in line with results on the degradability of Methyl acetate: the ready biodegradability of methyl acetate has been proven to be readily biodegradable in a closed bottle test according to OECD 301 D and a modified MITI test according to OECD 301 C. In conclusion, based on reliable experimental data for both source substances and by applying a read across approach in compliance with section 1 of REACH Annex XI the target substance is considered to be readily biodegradable.