Octanoic acid, mixed tetraesters with 2-ethylhexanoic acid, heptanoic acid and pentaerythritol

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:

key study

Study period:

The study was conducted between 27 August 2004 and 24 September 2004.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

Standard activated sludge (sludge No. 160827), which was obtained from Chemical Biotesting Center of Chemicals Evaluation and Research Institute, Japan, on August 27th, 2004, and had been cultured and maintained in the laboratory.

Duration of test (contact time):

28 d

Initial conc.:

101.1 mg/L

Based on:

act. ingr.

Details on study design:

TEST CONDITIONS
- Test temperature: 25 degree celsius
- pH: 7.25

TEST SYSTEM
- Culturing apparatus: Coulometer, Ohkura Electric Co., Ltd. OM-2001A type
- Number of culture flasks: 3
- Measuring equipment: Data sampler, Asahi TechneionCo.,Ltd. DS-3SAMPLING
- Sampling frequency: 7, 14, 21, 28 d

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: Yes

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

60

Sampling time:

28 d

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the test conditions, the test substance was considered to be readily biodegradable.

Executive summary:

A study was conducted to determine the ready biodegradability of the substance according to OECD Guideline 301C (modified MITI test). Standard activated sludge was exposed to 101.1 mg/L of the test substance under aerobic conditions for 28 d in culture flasks. A reference substance (aniline), an abiotic control and inoculum blanks were maintained simultaneously. Sampling was performed on Day 7, 14, 21 and 28 and the % biodegradation was calculated based on oxygen consumption. The results showed that the biodegradation of the test substance was an average of 60% after 28 d. The degree of biodegradation of aniline was 67% in 7 d and 75% after 14 d, hence the study was considered to be valid. Under the study conditions, the substance was considered to be readily biodegradable (Koei, 2004).

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

The study was conducted between 6 June 2006 and 4 July 2006.

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

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: From the aeration tank of a municipal sewage treatment plant, ARA Werdhölzli, 8048 Zürich, Switzerland
- Pretreatment: No

Duration of test (contact time):

28 d

Initial conc.:

22.1 mg/L

Based on:

TOC

Initial conc.:

21.8 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium, prepared with deionised water
- Test temperature: 22.0 ± 0.5°C
- pH: 7.4 ± 0.2
- pH adjusted: yes with NaOH or H2SO4
- Aeration of dilution water: with CO2-free air
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: 2500 mL glass bottles containing 2000 mL test solution;
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aerated with CO2-free air and fitted to gas-absorbtion bottles containing 125 mL of 0.15 M NaOH
- Measuring equipment: Shimadzu 5050 TOC-Analyzer using the NPOC-mode

SAMPLING
- Sampling frequency: Days 0, 1, 3, 7, 10, 14, 17, 21, 24 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg/L (TOC)

Key result

Parameter:

% degradation (CO2 evolution)

Value:

96

Sampling time:

28 d

Results with reference substance:

The reference substance was degraded to 96.9% by Day 14.

The test substance is readily biodegradable under conditions tested. The biodegradation was > 60% within 28 d and reached 84% at the end of the 10-day-window.

Table 1: Percentage biodegradation of test and reference substance.

Day	Test substance (% degradation)	Reference susbtance (% degradation)
0	0.0	0.0
1	0.6	4.6
3	5.3	45.2
7	52.1	81.2
10	71.5	92.8
14	86.6	96.7
17	91.7	97.6
21	93.1	98.0
24	96.3	97.8
28	96.0	96.9

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the study conditions, the substance was considered to be readily biodegradable.

Executive summary:

A study was conducted to determine the ready biodegradability of the substance according to OECD Guideline 301B and EU Method C.4 -C, in a non-GLP set-up. Activated sludge from a municipal sewage treatment plant was exposed to the test substance at 22.1 mg/L (based on TOC level) under aerobic exposure conditions. An inoculum blank and a reference substance (sodium benzoate) were also maintained in this study. The biodegradability based on CO2 evolution of the test substance was calculated to be 96% of the theoretical value (ThCO2) after an incubation time of 28 days. The biodegradation of the test substance reached 84% at the end of the 10-d window. The positive control, sodium benzoate, reached 97% biodegradation after 14 d, thus confirming suitability of inoculum and test conditions. The calculated biodegradation based on DOC measurement reached 96% for the test substance and 99% for sodium benzoate. Under the study conditions, the substance was considered to be readily biodegradable (BASF, 2004).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A study was conducted to determine the ready biodegradability of the substance according to OECD Guideline 301C (modified MITI test). Standard activated sludge was exposed to 101.1 mg/L of the test substance under aerobic conditions for 28 d in culture flasks. A reference substance (aniline), an abiotic control and inoculum blanks were maintained simultaneously. Sampling was performed on Day 7, 14, 21 and 28 and the % biodegradation was calculated based on oxygen consumption. The results showed that the biodegradation of the test substance was an average of 60% after 28 d. The degree of biodegradation of aniline was 67% in 7 d and 75% after 14 d, hence the study was considered to be valid. Under the study conditions, the substance was considered to be readily biodegradable (Koei, 2004).

A study was conducted to determine the ready biodegradability of the read-across substance CAS 68424 -31 -7 according to OECD Guideline 301B and EU Method C.4 -C. Activated sludge from a municipal sewage treatment plant was exposed to the test substance at 22.1 mg/L (based on TOC level) under aerobic exposure conditions. An inoculum blank and a reference substance (sodium benzoate) were also maintained in this study. The biodegradability based on CO2 evolution of the test substance was calculated to be 96% of the theoretical value (ThCO2) after an incubation time of 28 days. The biodegradation of the test substance reached 84% at the end of the 10-d window. The positive control, sodium benzoate, reached 97% biodegradation after 14 d, thus confirming suitability of inoculum and test conditions. The calculated biodegradation based on DOC measurement reached 96% for the test substance and 99% for sodium benzoate. Under the study conditions, the substance was considered to be readily biodegradable (BASF, 2006).