2-(2-aminoethylamino)ethanol

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Nov 2020 - 24 Dec 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-(2-aminoethylamino)ethanol

EC Number:

203-867-5

EC Name:

2-(2-aminoethylamino)ethanol

Cas Number:

111-41-1

Molecular formula:

C4H12N2O

IUPAC Name:

2-[(2-aminoethyl)amino]ethan-1-ol

Test material form:

liquid: viscous

Details on test material:

Physical Description: Colourless viscous liquid

Purity/Composition correction factor: No correction factor require

Storage Conditions: At room temperature protected from light container flushed with nitrogen

Test item handling: Use amber glassware or wrap container in aluminum foil

Specific details on test material used for the study:

The stability of the test substance was determined using Infra Red (CRL study no. 20230572). For the ready biodegradability study an infrared absorption spectrum was obtained at the end of the study. The infrared absorption spectrum was comparable to other spectra tested in this study. From this it could be concluded that the test item was stable during the ready biodegradability study.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Storage conditions: The freshly obtained sludge was kept under continuous aeration until further treatment.
- Concentration of suspended solids: 3.07 g/L in the concentrated sludge 30.7 mg suspended solids/L in the test vessels.
- Preparation of inoculum for exposure: The sludge was coarsely sieved (1 mm).

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

79 mg/L

Based on:

ThOD

Initial test substance concentration 2

Initial conc.:

29 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of the mineral medium: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon. Mineral medium, prepared according to OECD 301A
- Test temperature: 22°C
- pH at test start: 7.4-7.6
- pH at test end: 7.2 - 8.3
- pH adjusted: no
- Suspended solids concentration: the concentration of suspended solids (SS) was determined to be 3.07 g/L in the concentrated sludge as used for the test. The sludge was used as inoculum at a concentration of 10 mL per liter of mineral medium, leading to a final concentration SS of 30.7 mg/L. The SS was slightly above the 30 mg/L and the test item could not be classified as readily biodegradable in this best case situation, therefore there was no impact on the overall conclusion of the test item in the current study.
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 500 mL amber glass bottles. The end volume of medium was 244 mL, in order to obtain the required headspace-to-volume ratio.
- Number of culture flasks/concentration:
Test suspension: containing test item and inoculum (2 bottles).

PREPARATION OF THE TEST VESSELS
A stock solution of 1 g/L was prepared by adding a weight amount of 250 mg of test item in mineral medium. After stirring for 30 minutes, the final stock solution was clear and colourless, Aliquots of 7 ml of the stock solution were added to the test item bottles an the toxicity control.
At the start of the test (Day 0), test and/or procedural control item were added to the respective bottles. The volumes of suspensions were made up to 244 mL using inoculated mineral medium.
Rubber gaskets containing an appropriate amount of CO2 absorber were inserted into each bottle. Subsequently, each bottle was sealed by screwing an automated respirometer head on top.
- CO2 Absorber: Soda lime pellets (Merck, Darmstadt, Germany).
- Measuring equipment: Lovibond BD600-GLP manometric respirometry system, equipped with an inductive stirring system.
- Details of trap for CO2: The CO2 produced in each test bottle reacted with the CO2 absorbent in the rubber gaskets. As gaseous O2 was converted into gaseous CO2 that was absorbed, the gas pressure in the test system slowly decreased. This decrease in air pressure was measured by the respirometer heads and automatically converted into oxygen consumption (mg O2/L). Measurements were recorded automatically for 28 days, two times a day.

CONTROL AND BLANK SYSTEM
- Inoculum blank: containing only inoculum (2 bottles).
- Procedural control: containing procedural control item and inoculum (1 bottle).
- Toxicity control: containing inoculum, test item and procedural control item in amounts contributing equally to the total ThOD (1 bottle).

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

40

Sampling time:

28 d

% Degradation 2

Key result

Parameter:

% degradation (CO2 evolution)

Value:

45

Sampling time:

28 d

Details on results:

The relative biodegradation values calculated from the measurements performed during the test period revealed 45% and 40% biodegradation of the test item based on ThOD, for the duplicate bottles tested.
In the toxicity control, more then 25% biodegradation occurred within 14 days (52% based on ThOD). Therefore, the test item was considered not to inhibit microbial activity.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

See overall remarks, attachments

Interpretation of results:

not readily biodegradable

Conclusions:

2-(2-aminoethylamino)ethanol was not readily biodegradable under the conditions of the Manometric Respirometry Test.

Executive summary:

The test item 2-(2-aminoethylamino)ethanol was evaluated for its ready biodegradability in an aerobic aqueous medium with microbial activity introduced by inoculation with activated sludge., according to OECD guideline 301F and GLP principles. The test item was tested in duplicate at a target concentration of 29 mg/L, corresponding to a ThOD of 79 mgO2/L. Additionally two inoculum blanks, one procedural control and one toxicity control were tested. The relative biodegradation values calculated from the measurements performed during the test period revealed 40 % and 45 % biodegradation of the test item based on ThOD, for the duplicate bottles tested. In the toxicity control, 52% biodegradation occurred within 14 days. Therefore, the test item was considered not to inhibit microbial activity.
In conclusion, 2-(2-aminoethylamino)ethanol was not readily biodegradable under the conditions of the test presently performed. The study fulfilled all validity criteria of OECD 301F and is considered reliable without restrictions.