2-dimethylaminoethanol

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): In March, June, September, and December, sludge was sampled at the following 10 places in Japan: 1. Fukogawa city sewage plant, 2. Fukashiba industry sewage plant, 3. Nakahame city sewage plant, 4. Ochiai city sewage plant, 5. Kitakami river, 6. Shinano river, 7. Yoshino river, 8. Lake Biwa, 9. Hiroshima bay, 10. Dookai bay; sampling: 1. City sewage: Returned sludge from sewage plants was taken. 2. Rivers, lake and sea: Surface water and surface soil which were in contact with atmosphere were collected.
- Method of cultivation: about 30 minutes after ceasing aeration to the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then the equal volume of dechlorinated water was added to the remaining portion and aerated again, followed by addition of synthetic sewage at a concentration of 0.1 % (w/v). This procedure was repeated once every day. The culturing was carried out at 25 +/- 2 °C. 5 L of the filtrate of the supernatant of old activated sludge was mixed with 500 mL of the filtrate of the supernatant of new sludge and cultured at pH 7.0 +/- 1.0 under sufficient aeration using prefiltered open air. During the cultivation, appearance of the supernatant, precipitability, formation of flock, pH, dissolved oxygen concentration in the solution and temperature were checked and necessary adjustments were made. Microflora in the activated sludge was microscopically observed and sludge with no abnormal symptoms was used for the test.
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: 3 mL each of four stock solutions, as described in JIS K 0102-1986-21, are diluted to 1000 mL with purified water
- pH: 7.0
- pH adjusted: yes
- Suspended solids concentration: determined according to Method Japanese Industrial Standards (JIS) K 0102-1986-14.1

TEST SYSTEM
- Culturing apparatus: Closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co., Ltd.); 300 mL vessel, absorbent for evolving carbon dioxide Soda lime No. I (extra pure reagent, Wako Pure Chemical Industries, Ltd.)
- Number of culture flasks/concentration: 1
- Measuring equipment: Coulometer, Okhura Electric Co., Ltd.
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: soda lime, extra pure, Wako Pure Chemical Industries, Ltd.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

60.5

Sampling time:

14 d

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The substance is readily biodegradable.

Executive summary:

2 -dimethylaminoethanol was found to be readily biodegradable according to OECD criteria (Japan Chemical Industry Ecology - Toxicology & Information Center; JETOC, 1992). Under aerobic conditions a mixture of sewage, soil and natural water was used as inoculum to conduct the test according to OECD guideline 302 C. The initial test concentration was 100 mg/L, O2 consumption was the chosen parameter for biodegradation estimation. 60.5 % degradation of test substance was regarded after 14 days sampling time.

Description of key information

2-dimethylaminoethanol is considered to be readily biodegradable according to OECD criteria (JETOC, 1992).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

2 -dimethylaminoethanol was found to be readily biodegradable according to OECD criteria (Japan Chemical Industry Ecology - Toxicology & Information Center; JETOC, 1992). Under aerobic conditions a mixture of sewage, soil and natural water was used as inoculum to conduct the test according to OECD guideline 302 C. The initial test concentration was 100 mg/L, O2 consumption was the chosen parameter for biodegradation estimation. 60.5 % degradation of test substance was regarded after 14 days sampling time.

Biodegradation of dimethylethanolamine (DMAE, CAS 108-01-0) and further 42 amine compounds was determined in the supporting study: a marine biodegradability test by Eide-Haugmo et al. (2012), conducted according to the OECD guideline 306, “Biodegradability in seawater” (OECD, 1992). As test medium for the biodegradation test, aged and fortified seawater was used. The seawater was collected from an expected non-polluted location (90 m depth in the Trondheimsfjord, Norway) and filtered, after which it was stored in the dark for 2–5 days in 10-L tanks at 20 ± 2°C for degradation of inherent organic materials (aging). The aged seawater was aerated for 20 min and fortified with nutrient solutions enhancing bacterial growth. Test solutions were prepared by diluting the compound tested to 2 mg/L. After an incubation period of 28 days degradation rate of DMAE was 94 % (BOD28, based on % of ThOD).