N-(2-hydroxyethyl)-N-[2-[(1-oxooctyl)amino]ethyl]-β-alanine

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

Study period:

2007-03-28 to 2007-04-26

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:

adopted July 17th, 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted December 1992

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant‘, ‘s-Hertogenbosch, the Netherlands
- Preparation of inoculum for exposure: The sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 4.4 g/L in the concentrated sludge (information obtained from the municipal sewage treatment plant). Before use, the sludge was allowed to settle (51 minutes) and the liquid was decanted for use as inoculum at the amount of 10 mL/L of mineral medium.
- Pretreatment: Mineral components, Milli-RO water (ca. 80% total volume) and inoculum (1% final volume) were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.
- Concentration of sludge: 10 mL/L mineral medium

Duration of test (contact time):

28 d

Initial conc.:

12 mg/L

Based on:

TOC

Initial conc.:

38 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Stock solutions of mineral components: A) 8.50 g KH2PO4, 21.75 g K2HPO4, 0.50 g NH4Cl dissolved in Milli-Q water and made up to 1 litre, pH74 ± 02
B) 22.50 g MgSO4 x 7H2O dissolved in Milli-Q water and made up to 1 litre.
C) 36.40 g CaCl2.x 2H2O dissolved in Milli-Q water and made up to 1 litre.
D) 0.25 g FeCl3 x 6H2O dissolved in Milli-Q water and made up to 1 litre.
1 litre mineral medium contains: 10 ml of solution (A), 1 ml of solutions (B) to (D) and Milli-RO water.

- Test temperature: Between 21.1 and 23°C
- pH: between 7.4 and 7.6
- pH adjusted: no
- Aeration of dilution water: no
- Suspended solids concentration: 4.4 g/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: The test substance and positive control were added to the bottles containing the microbial organisms and mineral components (ca. 80% of total volume). The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before. Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit air line of each test bottle.
- Number of culture flasks/concentration: 2 for the test item, 2 for the inoculum blanks, 1 for the positive control and 1 for the toxicity control.
- Method used to create aerobic conditions: Mineral components and inoculum were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.

- Measuring equipment: Observations/measurements in the study were recorded electronically using the following programme(s): REES version 1.5 (REES scientific, Trenton, NJ, USA): Temperature. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCI (1:20 dilution from 1 M HCI (Titrisol® ampul), Merck, Darmstadt, Germany).
- Details of trap for CO2 and volatile organics if used: A mixture of oxygen (21%) and nitrogen (79%) was passed through a bottle, containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was sparged through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 mL/min).

SAMPLING
- Sampling frequency: On days 2, 5, 7, 9, 14, 19, 23, 27, 29

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 bottles
- Toxicity control: 1 bottle including the test item and a sodium acetate solution

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Remarks:

mean of duplicates

Value:

41

Sampling time:

28 d

Parameter:

% degradation (CO2 evolution)

Remarks:

toxicity control

Value:

42

Sampling time:

14 d

Details on results:

The relative degradation values calculated from the measurements performed during the test period revealed 38 and 45% degradation of the test item, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.

In the toxicity control more than 25% degradation occurred within 14 days (42%, based on ThCO2) . Therefore, the test substance was assumed not to inhibit microbial activity.

Results with reference substance:

The positive control substance was degraded by at least 60% (75%) within 14 days.

Validity criteria:

The positive control substance was degraded by at least 60% (75%) within 14 days.

The difference of duplicate values for %-degradation of the test item was always less than 20.

The total CO2 release in the blank at the end of the test did not exceed 40 mg/L (56.4 mg CO2 per 2 Iitres of medium, corresponding to 28.2 mg/L).

The IC content of the test substance (suspension) in the mineral medium at the beginning of the test was less than 5% of the TC.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Amphopropionate C8 was degraded significantly (38 and 45%) during the test period. However, since at least 60% biodegradation was not reached within 10 days immediately following the attainment of 10% biodegradation (10-day window), the criterion for ready biodegradability was not met. Thus, under the conditions of this test Amphopropionate C8 was not readily biodegradable.

Executive summary:

The biodegradation of of Amphopropionate C8 (50.6% a.i.) was investigated over a 28-day period in a CO2 Evolution Test according to OECD guideline 301 B (1992) and EU method C.4-C (1992). The test medium was inoculated with activated sludge from a sewage treatment plant mainly fed with municipal wastewater. The rate of degradation was monitored by measuring the carbon dioxide produced over the 28-d period.

The test item was tested with a concentration of 38 mg/L in duplicates, corresponding to a carbon content (TOC) of 12.0 mg C/L in the test vessels.

The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29. After the soluble CO2 was turned out over a period of 24 h.

The percentage CO2 production was calculated in relation to the theoretical CO2 (ThCO2) of the test item. The biodegradation was calculated for each titration time.

The relative degradation values calculated from the measurements performed during the test period revealed 38 and 45% degradation of the test item, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.

To check the activity of the test system sodium acetate was used as functional control. The percentage of degradation of the functional control reached the pass level of 60% (75%) within 14 days. 

In the toxicity control more than 25% degradation occurred within 14 days (42%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.

The test item Amphopropionate C8 is not readily biodegradable in this CO2 evolution test, but may be considered to be inherently biodegradable. The substance is not inhibitory to microorganisms at a concentration of 38 mg/L.

Description of key information

inherently biodegradable (38 to 45% degradation after 28 d; 10 d window criterion not fulfilled); OECD TG 301B / EU method C.4 -C (CO2 Evolution Test); RL1; GLP

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

The biodegradation of Amphopropionate C8 (50.6% a.i.) was investigated over a 28-day period in a CO2 Evolution Test according to OECD guideline 301 B (1992) and EU method C.4-C (1992). The test medium was inoculated with activated sludge from a sewage treatment plant mainly fed with municipal wastewater. The rate of degradation was monitored by measuring the carbon dioxide produced over the 28-d period.

The test item was tested with a concentration of 38 mg/L in duplicates, corresponding to a carbon content (TOC) of 12.0 mg C/L in the test vessels.

The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29. After the soluble CO2 was turned out over a period of 24 h.

The percentage CO2 production was calculated in relation to the theoretical CO2 (ThCO2) of the test item. The biodegradation was calculated for each titration time.

The relative degradation values calculated from the measurements performed during the test period revealed 38 and 45% degradation of the test item, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.

To check the activity of the test system sodium acetate was used as functional control. The percentage of degradation of the functional control reached the pass level of 60% (75%) within 14 days. 

In the toxicity control more than 25% degradation occurred within 14 days (42%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.

The test itemAmphopropionate C8is not readily biodegradable in this CO2 evolution test, but may be considered to be inherently biodegradable. The substance is not inhibitory to microorganisms at a concentration of 38 mg/L.