2-[[3-(dimethylamino)propyl]methylamino]ethanol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-10-15 to 2014-11-14 (experimental phase)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Commission Regulation 440/2008/EC, Method C.9 of May 30, 2008: Zahn-Wellens Test (EEC Publication No. L 142/538, May 2008)

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Version / remarks:

OECD Guideline for Testing of Chemicals No. 302 B: "Inherent Biodegradability: Zahn-
Wellens/EMPA Test", adopted July 17, 1992

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Supplied by the sewage plant Roßdorf, Germany
- Pretreatment: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted.
The solid material was re-suspended in tap water and again centrifuged. This procedure was repeated three times. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 4 g dry material per litre were mixed with test water and then aerated until use.
- Concentration of sludge: 4 g dry material per litre
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

50 mg/L

Based on:

DOC

Initial conc.:

83.4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Reconstituted Test Water (please see section "Any other information on materials and methods incl. tables" for further information on the composition)
- Test temperature: 21- 22 °C
- pH: The pH of the test water was 7.6.
- CEC (meq/100 g):
- Aeration of dilution water: not specified
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Cylindrical glass flasks with 3 litre volume were covered with a plastic lid.
- Number of culture flasks/concentration: 2 per test item, 1 procedure control, 2 inoculum blank controls and 1 toxicity control
- Method used to create aerobic conditions: Culturing apparatus were aerated using a glass tube. The air was led through a bottle containing deionised water to clarify and moisture the air. Also the air was filtered through cotton wool (inserted 4 h after test start). The air-flow was adjusted to achieve a concentration > 1 mg/L DOC in the test media during the test period.

SAMPLING
- Sampling frequency: Samples were taken on day 0 at test start and after 3 hours test duration, and on days 4, 7, 11, 14, 21, 27 and 28.
- Sampling method: On each sampling day, water evaporation loss was compensated by adding deionized water (except at day 0), deposits were scraped off. Per sample a volume of approximately 40 mL was taken using a one-way syringe. Samples were filtered through a 0.45 μm filter (Cellulose mixed ester). The remaining sample was used for analysis.
- Measuring equipment: The filtered samples were analysed for DOC by means of catalytic combustion, TOC-V CPH analyser and ASI-V autosampler, Shimadzu, Duisburg, Germany.

CONTROL AND BLANK SYSTEM
- Inoculum blank: An amount of sludge corresponding to 0.2 g dry material was added per litre of final test medium in each of the two inoculum blank controls.
- Toxicity control: 166.8 mg of test material, 220.0 mg Diethylene glycol and activated sludge at a concentration of 0.2 g suspended solids per litre were filled up with test water to a volume of 2 L in the toxicity control.
- Other: 220.0 mg Diethylene glycol, corresponding to 50 mg DOC/L and activated sludge at a concentration of 0.2 g suspended solids per litre were filled up with mineral medium to a volume
of 2 litres in the procedure control.

Reference substance:

diethylene glycol

Key result

Parameter:

% degradation (DOC removal)

Value:

89.2

Sampling time:

28 d

Results with reference substance:

The reference item Diethylene glycol was sufficiently degraded to 101.0 % after 14 days, and to 98.4 % after 28 days of incubation.
The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum.

pH, Temperature and Dissolved Oxygen Determination
The pH-values were measured at each sampling day. At test start, an adjustment to pH 7.8 was done in vessels containing test item (test item vessels and toxicity control) since the pHvalues were between 8.1 and 8.2. In all other vessels and at all following sampling dates no adjustment was necessary as all pH values were in the valid range of 6.5 - 8.0.

The oxygen concentrations were determined each sampling day  .

The temperature was measured at least each sampling day by means of an electronic thermometer in all flaks.

 

Biodegradation in the Toxicity Control
In the toxicity control containing both, the test item and the reference item Diethylene glycol, 65.5% biodegradation was noted within 14 days and 91.8 % biodegradation was determined after 28 days of incubation. 
According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge microorganisms because degradation was > 25 % within 14 days.

 

Validity Criteria of the Study
The percentage degradation of the reference item must reach more than 70% biodegradation by day 14.
The biodegradation of the reference item reached more than 100% at day 14. The validity criterion was met.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The study was conducted according to OECD 302B (Inherent Biodegradability: Zahn-Wellens/EMPA Test) under GLP on the registered substance itself. There were no deficiencies in documentation and the validity criteria were met, wherefore the study can be considered as reliable.
Based on the results of the study the mean percentage biodegradation of the registered substance reached 89.19 % after 28 days of incubation under the test conditions. Since the percentage biodegradation is above 70 % based on DOC for the test item, this is evidence of inherent, ultimate biodegradability.

Executive summary:

In the present study the registered substance was investigated for its inherent biodegradability in a Zahn-Wellens/EMPA Test according to OECD 302B under GLP over a period of 28 days. The registered substance was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was determined by following the DOC (Dissolved Organic Carbon) of the registered substance in the incubation flasks during exposure.
As a reference item Diethylene glycol was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Under the conditions of the test the mean percentage biodegradation of the test substance reached 89.19 % after 28 days of incubation. Since the percentage biodegradation is above 70 % based on DOC for the registered substance as test item this is evidence of inherent, ultimate biodegradability.

The reference item Diethylene glycol was sufficiently degraded to 101.0 % after 14 days, and to 98.4 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

In the toxicity control containing both, the test item and the reference item Diethylene glycol, 65.5% biodegradation was noted within 14 days and 91.8 % biodegradation was determined after 28 days of incubation. Thus, the registered substance can be assumed to be not inhibitory to the activated sludge microorganisms.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-11-15 to 2013-12-13 (experimental phase)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

OECD Guidelines for Testing of Chemicals (1992) No. 301D, "Ready Biodegradability; Closed Bottle Test" referenced as Method C.4-E of Commission Regulation (EC) No. 440/2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Version / remarks:

of Commission Regulation (EC) No. 440/2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Version / remarks:

US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110 Paragraph (o)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): A mixed population of sewage treatment micro-organisms was obtained on 15 November 2013 from the final effluent stage of the Severn Trent Water Pic sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.
- Preparation of inoculum for exposure: The sample of effluent was filtered through coarse filter paper (first approximate 200 mL discarded) and the filtrate maintained on continuous aeration in a temperature-controlled room at approximately 21°C prior to use.
- Pretreatment: no

Duration of test (contact time):

28 d

Initial conc.:

1.5 mg/L

Based on:

test mat.

Remarks:

ThOD of test substance: 3.0 mg O2/mg

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: as recommended in OECD Guideline 301, details stated below in section 'Any other information', Table 1
- Additional substrate: none
- Test temperature: approx. 21°C
- pH: 7.5-7.6
- pH adjusted: yes, if necessary, using diluted HCl or NaOH
- Suspended solids concentration: 1 drop of inoculum per litre
- Aeration of dilution water: aeration prior to the test during preparation
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 250 mL Biological Oxygen Demand (BOD) bottles, darkened glass, with ground glass stoppers
- Number of culture flasks/concentration: 18, two flasks per sampling date
- Measuring equipment: dissolved oxygen meter and spectrophotometer
- Test performed in closed vessels due to significant volatility of test substance: yes
- Test performed in open system: no

SAMPLING
- Sampling frequency: Dissolved oxygen measurements on Day 0, 3, 5, 7, 11, 14, 18, 21 and 28 (control, reference and test substance) and on Day 0, 14 and 28 (toxicity control), respectively; nitrate and nitrite analysis were performed on each sampling occasion as well
- Sampling method: no specific sampling method described
- Sample storage before analysis: no storage

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, consisting of inoculated mineral medium
- Abiotic sterile control: no
- Toxicity control: yes, consisting of test substance (1.5 mg/L) and reference substance (1.5 mg/L in inoculated mineral medium
- Other: procedure control with 3.0 mg/L reference substance

STATISTICAL METHODS:
- no statistical evaluation needed

Reference substance:

benzoic acid, sodium salt

Remarks:

Batch no.: MKBJ3541V Purity: 99% Expiry Date: 01 July 2014

Key result

Parameter:

% degradation (DOC removal)

Value:

2

Sampling time:

28 d

Remarks on result:

other: not readily biodegradable

Details on results:

Nitrate and nitrite analysis of the test solutions at each sampling occasion confirmed that no significant oxygen consumption as a result of nitrification occurred during the test.
The toxicity control attained 29% biodegradation after 14 days and 30% biodegradation after 28 days therefore confirming that the test substance was not toxic to the sewage treatment microorganisms used in the test.

Parameter:

ThOD

Value:

3 g O2/g test mat.

Results with reference substance:

The reference item, sodium benzoate, attained 65% biodegradation after 14 days and 65% biodegradation after 28 days thereby confirming the suitability of the test method and culture conditions.

Validity criteria fulfilled:

yes

Remarks:

Oxygen depletion in blank control < 1.5 mg O2/L after 28d: yes Residual oxygen conc. in test vessels > 0.5 mg O2/L: yes Difference between extremes of replicate oxygen depletion values at test end <20%: yes

Interpretation of results:

not readily biodegradable

Conclusions:

The study was conducted according to OECD 301D (Ready Biodegradability: Closed Bottle Test) under GLP on the registered substance itself. There were no deficiencies in documentation and the validity criteria were met, wherefore the study can be considered as reliable.
Based on the results of the study the mean percentage biodegradation of the registered substance reached 2 % after 28 days of incubation under the test conditions. Since the percentage biodegradation is far below 60 % based on DOC for the test item, the test substance has to be classified as not readily biodegradable.

Executive summary:

In the present study the registered substance was investigated for its ready biodegradability in a Closed Bottle Test according to OECD 301D under GLP over a period of 28 days. The registered substance was exposed for 28 days to a mixed population of sewage treatment microorganims from the final effluent stage of a domestic waste water treatment plant. The biodegradation was determined by following the DOC (Dissolved Organic Carbon) of the registered substance in the incubation flasks during exposure.

As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Under the conditions of the test, the mean percentage biodegradation of the test substance reached 2% after 28 days of incubation. Since the percentage biodegradation is well below 60% based on DOC, the test item has to be regarded as not readily biodegradable.

The reference item sodium benzoate was sufficiently degraded to 65% after 14 days, thus confirming the suitability of the test method and culture conditions.

In the toxicity control containing both, the test item and the reference item, 29% biodegradation was noted within 14 days and 30% biodegradation was determined after 28 days of incubation. Thus, the registered substance can be considered as non-toxic to the sewage treatment microorganisms used in this test.

Description of key information

1) Ready Biodegradability (OECD 301D): 2% mean percentage biodegradation based on oxygen depletion after 28 days under test conditions; thus the substance 2-[[3-(dimethylamino)propyl]methylamino]ethanol cannot be considered as readily biodegradable under the strict terms and conditions of OECD Guideline No. 301D.

2) Inherent Biodegradability (OECD 302B): 89.19% mean percentage biodegradation after 28 days under test conditions; since the percentage biodegradation is above 70 % based on DOC for the substance 2-[[3-(dimethylamino)propyl]methylamino]ethanol, this is evidence of inherent, ultimate biodegradability.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater

Additional information

Inherent Biodegradability in a Zahn-Wellens/EMPA Test (OECD 302B)

In the present study the registered substance was investigated for its inherent biodegradability in a Zahn-Wellens/EMPA Test according to OECD 302B under GLP over a period of 28 days. The registered substance was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was determined by following the DOC (Dissolved Organic Carbon) of the registered substance in the incubation flasks during exposure.
As a reference item Diethylene glycol was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Under the conditions of the test the mean percentage biodegradation of the test substance reached 89.19 % after 28 days of incubation. Since the percentage biodegradation is above 70 % based on DOC for the registered substance as test item this is evidence of inherent, ultimate biodegradability.

The reference item Diethylene glycol was sufficiently degraded to 101.0 % after 14 days, and to 98.4 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

In the toxicity control containing both, the test item and the reference item Diethylene glycol, 65.5% biodegradation was noted within 14 days and 91.8 % biodegradation was determined after 28 days of incubation. Thus, the registered substance can be assumed to be not inhibitory to the activated sludge microorganisms.

Ready Biodegradability in a Closed Bottle Test (OECD 301D)

In the present study the registered substance was investigated for its ready biodegradability in a Closed Bottle Test according to OECD 301D under GLP over a period of 28 days. The registered substance was exposed for 28 days to a mixed population of sewage treatment microorganims from the final effluent stage of a domestic waste water treatment plant. The biodegradation was determined by following the DOC (Dissolved Organic Carbon) of the registered substance in the incubation flasks during exposure.

As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Under the conditions of the test, the mean percentage biodegradation of the test substance reached 2% after 28 days of incubation. Since the percentage biodegradation is well below 60% based on DOC, the test item has to be regarded as not readily biodegradable.

The reference item sodium benzoate was sufficiently degraded to 65% after 14 days, thus confirming the suitability of the test method and culture conditions.

In the toxicity control containing both, the test item and the reference item, 29% biodegradation was noted within 14 days and 30% biodegradation was determined after 28 days of incubation. Thus, the registered substance can be considered as non-toxic to the sewage treatment microorganisms used in this test.