3-cyclohexylaminopropylamine

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

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)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OTS 796.3260 (Ready Biodegradability: Modified Sturm Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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): Municipal sewage treatment plant, 31137 Hildesheim, Germany. Activated sludge from the sewage plant at Hildesheim is well suited as it receives predominantly municipal sewage and hardly any industrial chemical waste.
- Laboratory culture: No
- Method of cultivation: -
- Storage conditions: -
- Storage length: -
- Preparation of inoculum for exposure: The activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration with CO2 free air for two days before test start.
- Pretreatment: No
- Concentration of sludge: The amount of inoculum used to initiate inoculation was 4.08 mL/L (25.0 mg/L dw).
- Initial cell/biomass concentration: Approx. 107 - 108 CFU/L
- Water filtered: no
- Type and size of filter used, if any: -

Duration of test (contact time):

28 d

Initial conc.:

15 mg/L

Based on:

test mat.

Initial conc.:

0.692 other: mg C/ mg

Based on:

test mat.

Remarks:

TOC

Initial conc.:

2.54 other: mgC02/mg

Based on:

test mat.

Remarks:

ThC02

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium acc. to OECD 301 B / CO2 Evolution Test
- Additional substrate: No
- Solubilising agent (type and concentration if used): No
- Test temperature: 20.5 – 23.0 °C
- pH: 7.59 (Inoculum Control on day 28)
- pH adjusted: no
- Aeration of dilution water: yes
- Suspended solids concentration: 15.0 mg/L, corresponding to a carbon content of 10.4 mg C/L in the test vessel
- Continuous darkness: no (low light conditions; brown glass bottles)
TEST SYSTEM
- Method used to create aerobic conditions: Aeration through CO2 free air production system.
- Measuring equipment: Gas wash bottle containing 100 mL of a 0.0125mol/L Ba(OH)2 solution.
- Test performed in closed vessels due to significant volatility of test substance: No
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: Determination of CO2 was carried out by titration subsequent to complete adsorption of the released CO2 in an alkaline solution (0.0125 mol/L Ba(OH)2).
SAMPLING
- Sampling frequency: Three times a week during the first ten days and thereafter twice weekly.
- Sampling method: Connection of the CO2 adsorption vessels to the air outlet of the incubation vessels
- Sterility check if applicable: not specified
- Sample storage before analysis: not specified
CONTROL AND BLANK SYSTEM
- Inoculum blank: Test medium without test and/or reference item
- Abiotic sterile control: not specified
- Toxicity control: Test item and reference item (Sodium benzoate) in test concentration
STATISTICAL METHODS: not specified

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

1.5

Sampling time:

8 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

9

Sampling time:

14 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

45.5

Sampling time:

21 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

71

Sampling time:

28 d

Results with reference substance:

The adaptation phase of the functional control changed within 4 days into the degradation phase (degradation >= 10%). The course of the degradation was rapid and the functional control reached the pass level of 60% within 8 days and a maximum biodegradation of 90% on day 28.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Under the test conditions the test item is classified as readily biodegradable within the 28-day period of the study, but failing the 10-day window.

Executive summary:

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test according to OECD 301 B.

The test item was tested at a concentration of 15.0 mg/L with 2 replicates corresponding to a carbon content (TOC) of 10.4 mg C/L in the test vessels. The test vessels were incubated at low light conditions and at a temperature of 22 ± 2 °C.

The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification of the test solutions. The last titration was made on day 29 after residual CO2 had been purged from the test solutions over a period of 24 hours. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. The biodegradation was calculated for each titration time.

To check the activity of the test system sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% within 8 days and a maximum biodegradation of 90% on day 28. In the toxicity control containing both test and reference item a biodegradation of 55% was determined within 14 days, with 89% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

The biodegradation of the test item reached the 10% level (beginning of biodegradation) within 15 days. Both test item replicates reached the 60% pass level on day 28. The mean biodegradation on day 28 was 71%.

In conclusion, under the test conditions the test item is classified as readily biodegradablewithin the 28 -day period of the study but failing the 10 -day-window.

Description of key information

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test according to OECD 301 B.

The test item was tested at a concentration of 15.0 mg/L with 2 replicates corresponding to a carbon content (TOC) of 10.4 mg C/L in the test vessels. The test vessels were incubated at low light conditions and at a temperature of 22 ± 2 °C.

The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2 produced by the respiration of bacteria. The degradation was stopped on day 28 by acidification of the test solutions. The last titration was made on day 29 after residual CO2 had been purged from the test solutions over a period of 24 hours. The percentage CO2 production was calculated in relation to the theoretical CO2 production (ThCO2) of the test item. The biodegradation was calculated for each titration time.

To check the activity of the test system sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60% within 8 days and a maximum biodegradation of 90% on day 28. In the toxicity control containing both test and reference item a biodegradation of 55% was determined within 14 days, with 89% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

The biodegradation of the test item reached the 10% level (beginning of biodegradation) within 15 days. Both test item replicates reached the 60% pass level on day 28. The mean biodegradation on day 28 was 71%.

In conclusion, under the test conditions the test item is classified as readily biodegradable within the 28 -day period of the study but failing the 10 -day-window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window

Type of water:

freshwater