[No public or meaningful name is available]

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:

Experiment start date - 21 March 2005; Experiment completion date - 20 April 2005; Study completion date - 31 May 2005.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: FAT 40819/A
Description: Red brown powder
Batch number: Red ROE 420 BOP 01/04
Purity: approx. 77 %
Stability of test item: Stable under storage condition
Expiry date: 02 November 2009
Storage conditions: At room temperature.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

The study was performed with aerobic activated sludge from a wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) treating predominantly domestic wastewater. The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated. Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (±10 %) dry material per liter. During holding, the sludge was aerated at room temperature until use. Prior to use, the sludge was diluted with test water to a concentration of 1 g per liter (dry weight basis). This diluted activated sludge was used as inoculum to give a final concentration of 30 mg dry material per liter.

Duration of test (contact time):

28 d

Initial conc.:

98.5 mg/L

Based on:

test mat.

Initial conc.:

66 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

- Apparatus: The test flasks (500 mL Erlenmeyer flasks, labeled with all necessary information to ensure unmistakable identification) were incubated under continuous stirring in a SAPROMAT D12 (Voith GmbH, Heidenheim, Germany)). Oxygen consumption was recorded manually by taking a daily reading at least each working day.
- Principle: Electro-chemical analysis process: The biodegradation process consumes the dissolved oxygen in the liquid and generates CO2. The CO2 is adsorbed by soda lime and the total pressure decreases in the airtight test flasks. The pressure drop is detected and converted into an electrical signal by means of an electrode type manometer. The consumed oxygen is replaced by electrolytically generated oxygen from a copper sulfate solution.
- Light conditions: Darkness
- Test temperature: 22 °C, maintained with a built-in thermostat and checked once per week.
- pH: Prior to test start, the pH was measured in each test flask before the addition of the activated sludge inoculum. At the end of incubation the pH was measured again in each test flask.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

- The percent biodegradation of the test item was calculated based on the chemical oxygen demand (COD) of 0.67 mg O2/mg test item. The biochemical oxygen demand (BOD) of the test item FAT 40819/A in the test media was in the range of the inoculum controls throughout the study period of 28 days.
- Consequently, FAT 40819/A was found not to be biodegradable under the conditions of the test within 28 days.
- No degradation of the test item occurred in the abiotic control under the conditions of the test.

Parameter:

COD

Value:

670 mg O2/g test mat.

Parameter:

BOD5

Value:

0 mg O2/g test mat.

Results with reference substance:

- The percent biodegradation of the reference substance was calculated based on the ThOD of 1.67 O2/mg. The reference substance was degraded by an average of 87 % by exposure day 14, thus confirming suitability of the activated sludge. At the end of the test (day 28), the reference substance degraded by an average of 91 %.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test substance is not readily biodegradable under the conditions of the test within 28 days.

Executive summary:

In a GLP-compliant biodegradation study, the test substance was investigated for its ready biodegradability in a manometric respirometry test over 28 days according to OECD Guideline 301 F. No degradation occurred in the abiotic control. In the toxicity control, containing both the test substance and the reference item sodium benzoate, no inhibitory effect on the biodegradation of the reference item was determined. Thus, the test substance had no inhibitory effect on the activity of activated sludge microorganisms. The reference item sodium benzoate was degraded by 91 % on exposure day 28, thus confirming suitability of the activated sludge. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of the test substance were 670 mg and 0 O2/mg test item, respectively. Consequently, the test substance was found not to be biodegradable under the conditions of the test within 28 days.

Reference 2

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Experiment start date - 07 March 2005; Experiment end date - 05 April 2005; Study completion date - 31 May 2005.

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.9 (Biodegradation: Zahn-Wellens Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: FAT 40819/A
Description: Red brown powder
Batch number: Red ROE 420 BOP 01/04
Purity: approx. 77 %
Stability of test item: Stable under storage condition
Expiry date: 02 November 2009
Storage conditions: At room temperature.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

The study was performed with aerobic activated sludge from a wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) treating predominantly domestic wastewater. The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated. Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (±10 %) dry material per liter. During holding, the sludge was aerated at room temperature until use. Defined volumes of this diluted activated sludge were added to test water to obtain a final concentration of 300 mg dry material per liter. The ratio between inoculum and test item (based on the mean DOC measured) was 3:1.

Duration of test (contact time):

28 d

Initial conc.:

361.6 mg/L

Based on:

test mat.

Initial conc.:

96.9 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

- Test vessels: 2-Liter Erlenmeyer flasks, cleaned with alcoholic hydrochloric acid, rinsed with deionized water and dried. The final volume was 1000 mL per flask. Each flask was loosely covered with aluminum foil to allow the exchange of air between the flask and the surrounding atmosphere. The test media were continuously stirred by magnetic stirrers.
- Identification: The test vessels were labeled with all necessary information to ensure unmistakable identification.
- Test temperature: 22-25 °C. The inoculated flasks were incubated in a temperature controlled room. The temperature was checked on each sampling date in an inoculum control. Additionally, the room temperature was continuously recorded.
- pH: 6.8-7.5 (before adjustment). Prior to test start (after addition of the activated sludge inoculum) and before each sampling, the pH was measured in each test flask. If necessary, the pH was adjusted to 7.5 ± 0.5 with a diluted sodium hydroxide solution.
- Light conditions: The test flasks were incubated in the dark.
- Oxygen concentration: 5.4-8.6 mg O2/L. The oxygen concentration was measured at the start of the test and before each sampling.

Reference substance:

diethylene glycol

Parameter:

% degradation (DOC removal)

Value:

13

Sampling time:

28 d

Details on results:

- In the test flasks containing the test item and activated sludge (inoculum) the mean concentration of DOC (dissolved organic carbon) slightly decreased from initially 97 mg/L at Day 0 (starting value after 3 hours of exposure) to 84 mg/L at Day 28. The mean biodegradation of FAT 40819/A based on DOC decrease amounted to 13 %.
- No DOC-removal was observed during the first three hours of exposure indicating that the test item did not adsorb on activated sludge.
- In the abiotic control, containing the test item and poisoned mineral medium, no degradation was noted after 14 days of exposure. Further sampling was not possible, since the test flask broke after the 14-day sampling. However in the ready biodegradation study with FAT 40819/A (RCC Study No. 858115) it was shown that no abiotic degradation of the test item occurred during 28 days.
- In the toxicity control, containing the test item (corresponding to 49 % of total DOC), the reference item (corresponding to 51 % of total DOC) and activated sludge (inoculum), the initial DOC concentration of 193 mg/mL measured on Day 0 rapidly decreased by 52 % within the first 14 days of exposure. Thus, according to the test guidelines, the test item can be assumed not to be inhibitory to activated sludge at the tested concentration of 360 mg/L because degradation was clearly >35 % within 14 days of incubation.

Results with reference substance:

In the procedure control containing the reference item diethylene glycol and activated sludge (inoculum), the test item was completely (99 %) degraded within the first 10 days of exposure, thus confirming the suitability of the activated sludge.

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The test substance is not inherently biodegradable under the conditions of the test within 28 days.

Executive summary:

In a GLP-compliant study, performed according to OECD guideline 302B, the test substance was investigated for its potential inherent biodegradability in a Zahn-Wellens/EMPA test over 28 days. The reference item diethylene glycol was completely degraded within the first 10 days of exposure, thus confirming the suitability of the activated sludge. In the abiotic control no degradation was noted. In the toxicity control, biodegradation was observed, indicating that the test substance was not inhibitory to the activated sludge. In conclusion, the test substance was found to be not inherently biodegradable under the conditions of the test within 28 days. In the test flasks containing the test item and inoculum the mean concentration of DOC (dissolved organic carbon) decreased from 97 mg/L to 84 mg/L during the exposure period of 28 days. Expressed as percentage DOC removal, a mean biodegradation rate of 13 % was noted by the end of the test (day 28). No DOC-removal was observed during the first three hours of exposure indicating that the test item did not adsorb to activated sludge.

Description of key information

The test substance is neither readily nor inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

In a GLP-compliant biodegradation study, the test substance was investigated for its ready biodegradability in a manometric respirometry test over 28 days according to OECD Guideline 301 F. No degradation occurred in the abiotic control. In the toxicity control, containing both the test substance and the reference item sodium benzoate, no inhibitory effect on the biodegradation of the reference item was determined. Thus, the test substance had no inhibitory effect on the activity of activated sludge microorganisms. The reference item sodium benzoate was degraded by 91 % on exposure day 28, thus confirming suitability of the activated sludge. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of the test substance were 0.67 mg and 0 O2/mg test item, respectively. Consequently, the test substance was found not to be biodegradable under the conditions of the test within 28 days. In a GLP-compliant study, performed according to OECD guideline 302B, the test substance was investigated for its potential inherent biodegradability in a Zahn-Wellens/EMPA test over 28 days. The reference item diethylene glycol was completely degraded within the first 10 days of exposure, thus confirming the suitability of the activated sludge. In the abiotic control no degradation was noted. In the toxicity control, biodegradation was observed, indicating that the test substance was not inhibitory to the activated sludge. In conclusion, the test substance was found to be not inherently biodegradable under the conditions of the test within 28 days. In the test flasks containing the test item and inoculum the mean concentration of DOC (dissolved organic carbon) decreased from 97 mg/L to 84 mg/L during the exposure period of 28 days. Expressed as percentage DOC removal, a mean biodegradation rate of 13 % was noted by the end of the test (day 28). No DOC-removal was observed during the first three hours of exposure indicating that the test item did not adsorb to activated sludge.