Isobutyric acid, monoester with 2,2,4-trimethylpentane-1,3-diol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

Microorganisms were obtained from secondary effluent (Van Lare Wastetreatment Plant, Rochester, New York). The sludge was washed with laboratory dilution water. After centrifuging at approximately 7000 rpm for 15 minutes, the supernatant was decanted. This procedure was repeated two times. A small amount ofthe washed sludge was weighed, oven-dried (200°F, 4 min.), and reweighed. A calculation was made from these results to determine the amount of wet sludge to be suspended in water in order to obtain a mixed liquor suspended solids (MLSS) level of 2.0 g/L (± 10 percent). This level gives a concentration of 0.2 - 1.0 g/L of suspended solids in the test medium. The sludge was homogenized for 2 minutes in a blender and aerated until used. The inoculum was used on the day of collection.

Duration of test (contact time):

15 d

Initial conc.:

50 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard Basal Salts Medium
- Test temperature: 20-25C
- pH: 7.2 + or - 0.1
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 2 L Erlenmeyer flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration and stirring

SAMPLING
- Sampling frequency: Days 1,4,6,8, 11, and 15

CONTROL AND BLANK SYSTEM
- Inoculum blank: MNS + inoculum

Parameter:

% degradation (DOC removal)

Value:

99.5

Sampling time:

15 d

Details on results:

Starting DOC levels of the positive control solution and test article solutions A and B were 41.2 ppm, 38.0 ppm, and 38.1 ppm, respectively. On day 15, DOC levels for the positive control solution and test article solutions A and B were 0.4 ppm, -0.1 ppm, and 0.6 ppm, respectively. These values represent a loss of 99% DOC for the positive control and a loss of 99.5% DOC for the test article. Results from the two test flasks (A & B) were averaged.

Results with reference substance:

During the test the Positive Control Solution yielded DOC removals of 99% within 15 days.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Executive summary:

A 15-day biodegradation test was performed to determine the inherent biodegradability of the test article using the Zahn-Wellens/EMPA Test. The test inoculum was a sample of microorganisms in mixed liquor suspended solids from a municipal waste water treatment plant. Biodegradability was determined by measuring the loss of dissolved organic carbon (DOC) from the test chemical solution which contained 50 mg/L theoretical DOC at test start. There was an average 99.5% degradation of the test article measured by day 15. Because biodegradation was complete, the test was ended at that point. This extensive degradation shows that the test article is not persistent in the environment and that it can be considered inherently biodegradable according to the definitions of this test.

Reference 2

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:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

-Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Rochester, New York Van Lare Wastewater
Treatment Plant activated sludge
- Preparation of inoculum for exposure: On arrival the activated sludge was aerated for about 4 hours. Then, aproximately 1000 mL of the mixed liquor was collected and homoginized for two minutes with a mechanical blender. It was then settled for ~ 1 hour.
- Initial cell/biomass concentration: 10e6 organisms/mL

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard Basal Salts Medium (BSM)
- Additional substrate:
- Solubilising agent (type and concentration if used): None
- Test temperature: 22 + or - 2 degrees C
- pH: pH of BSM and positive control stock solution measured at test intiation and in all carboys on day 27.
- pH adjusted: prior to test only
- Aeration of dilution water: CO2 free air at a rate of 50-100 mL/minute (one to two bubbles per second) at a temperature of 22 + or - 2 degrees C
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: carboys
- Number of culture flasks/concentration: 2 for the inoculum blank, 1 for the positive control, and 2 for the test article
- Method used to create aerobic conditions: aeration with CO2 free air
- Measuring equipment: 3 CO2 absorber bottles connected in series to the exit airline of each carboy. Titration with HCl to measure barium hydroxide formed and calculate CO2 evolved
- Details of trap for CO2 and volatile organics if used: 100 mL of 0.0125M Barium hydroxide per trap



SAMPLING
- Sampling frequency: Days 0,1,3,6,8,10,13,16,20,23,27,28
- Sampling method: CO2 absorber bottle nearest carboy removed at each sampling interval, two remaining absorbers moved one place closer to carboy and fresh absorber bottle placed at far end of the series. Titration with 0.05N HCl.


CONTROL AND BLANK SYSTEM
- Inoculum blank: BSM
- Air line Control: Additional set of 3 CO2 absorbers connected directly to scrubbed air line and titrated in same manner as test.


STATISTICAL METHODS:
Spreadsheet (Lotus 123) used for data calculations and to generate graph illustrating percent degradation over time.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

65

Sampling time:

15 d

Remarks on result:

other: at end of 10 day window

Parameter:

% degradation (CO2 evolution)

Value:

> 77

Sampling time:

28 d

Parameter:

% degradation (DOC removal)

Value:

> 98

Sampling time:

28 d

Details on results:

10% degradation occured on approximately day 5. Replicate 1 achieved ~66% degradation in the 10-day window after 10% degradation had occurred.
Replicate 2 achieved ~64% degradation in the 10-day window after 10% degradation had occurred. At test termination on day 28 Replicates 1 and 2 had achieved 79% and 76% degradation respectively.

Results with reference substance:

Sodium benzoate positve control degraded 77% over the course of the test.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

A 28-day biodegradation test was performed to determine the ready biodegradability of the test substance. These results indicate that the test article was readily biodegradable under the test conditions.

Executive summary:

A 28-day biodegradation test was performed to determine the ready biodegradability of the test substance. A sample of activated sludge (mixed liquor suspended solids) from a domestic waste water treatment plant was used as the source of unacclimated microorganisms for the test. Biodegradability was determined by measuring the amount of carbon dioxide evolved from the test substance. The soluble test article was added as a stock solution to the test vessels. The test article at a theoretical concentration of 20 mg DOC/L showed 79% degradation (Test 1), and 76% degradation (Test 2). In order for the test substance to be classified as readily biodegradable, it must first reach 10%. Then it has a 10-day time window in which 60% degradation must occur. A lag phase of 4 days occurred before biodegradation reached 10%. The test substance reached 66% and 64% degradation within the 10-day time window. These results indicate that the test article was readily biodegradable under the test conditions.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

Microorganisms were obtained from secondary effluent (Van Lare Wastetreatment Plant, Rochester, New York). Viability of the microorganisms was confirmed after inoculation of the test solutions and activity was checked by means of a control substance. The sample was filtered through a coarse filter, and the first 200 mL were discarded. The filtrate was aerated until used (on the day of collection).

Duration of test (contact time):

42 d

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard Basal Salts Medium
- Test temperature: 20-25C
- pH: 7.2 + or - 0.1
- Aeration of dilution water: 30 minutes with CO2 free air
- Continuous darkness: yes



TEST SYSTEM
- Culturing apparatus: 2 L Erlenmeyer flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: pre-aeration and oscillation @ 100 rpm

SAMPLING
- Sampling frequency: Days 0, 7, 14, 21, 27, 34, 41, and 42.

CONTROL AND BLANK SYSTEM
- Inoculum blank: BSM + inoculum

Parameter:

% degradation (DOC removal)

Value:

ca. 33

Sampling time:

19 d

Remarks on result:

other: end of 10 day window

Parameter:

% degradation (DOC removal)

Value:

70

Sampling time:

34 d

Parameter:

% degradation (DOC removal)

Value:

90

Sampling time:

42 d

Details on results:

An approximate 8-day lag period was observed before any appreciable biodegradation took place. One day later, day 9, biodegradation had reached
the 10% level and by day 19, 33% degradation had occurred. The test substance did not reach the 70% level until day 34. It finished the test on day 42 with 90% biodegraded.

Results with reference substance:

During the test the Positive Control Solution yielded DOC removals of > 70% within 7 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Executive summary:

A 42-day biodegradation test was performed to determine the ready biodegradability of Texano Ester Alcohol using the Modified OECD Test (OECD Guideline 30lE, EEC/Annex V Guideline C.3). The test inoculum was a sample of microorganisms from the secondary effluent of a domestic wastewater treatment plant. Biodegradability was determined by measuring the loss of dissolved organic carbon (DOC) from the test chemical solution. The test chemical was not readily biodegradable according to the definitions of this test which requires 70% degradation within the time window of 10 days, counting from the day that the observed level of biodegradation first exceeds 10%. Considerable biodegradation of the test chemical did occur, however, based on the loss of 70% DOC by day 34 and 90% DOC by the end of the test on day 42. An approximate 8-day lag period was observed before any appreciable biodegradation took place. These data indicate that Texanol Ester Alcohol is unlikely to persist in the environment.

Description of key information

OECD 301B, 301E and 302B studies.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

This substance was tested for ready biodegradation by both OECD 301B and 301E guidelines. In the 301E study based upon DOC removal the substance only achieved 33% degradation within the 10 day window, but achieved 70% and 90% degradation at days 34 and 42 respectively. A subsequent test using method 301B based upon CO2 evolution exhibited 65% degradation in the 10-day window and >76% degradation at day 28. Based upon the 301B study this substance meets the criteria for readily biodegradable. An additional inherent biodegradation study showed >99.5% degradation at day 15 at which time the test was terminated.