Reaction products of stearic acid, diethylenetriamine and N-aminoethylethanolamine and acetic acid

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:

January 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Version / remarks:

2014

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: Liquid sewage (aerobic sludge), treatment plant of urban (about 66%) and industrial (about 34%)

Details on inoculum:

- Source of inoculum/activated sludge: BRIANZACQUE SRL (Monza), San Rocco - Monza (MB), Italia. Sludge was mixed in the laboratory and left to settle in aerobic conditions.
- Pre-treatment: Prior to use the sludge was analysed to determine its ability to form colony units. The sludge was later centrifuged, washed, and analysed to quantify the suspended solid concentration. The inoculum was prepared to have a suspended solid concentration of 4 mg/L.

Duration of test (contact time):

56 d

Initial conc.:

18.81 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

other: TIC (Total Inorganic Carbon)

Details on study design:

TEST CONDITIONS
- Composition of medium: Solution A: KH2PO4 (8.50 g/l); K2HPO4 (21.75 g/l); Na2HPO4. 2H2O (33.40 g/l), NH4 CI (0.50 g/l). Solution B: CaCl2 2H2O (36.40 g/l). Solution C: MgSO4 7H2O (22.50 g/l). Solution D: FeCl3.6 H2O (0.25 g/l). All solutions have been made with deionised water (MilliQ Millipore).
- Test temperature: 20 °C.
- Suspended solids concentration: 4 mg/L.
- Continuous darkness: Yes.
- Other: 12-hours before determining TIC, 6 ml sodium hydroxide (1 M) was added to one bottle each of the blank, reference substance, and test item in order to stop further reaction.

TEST SYSTEM
- Culturing apparatus: Glass bottles with hermetic seal (GHIARONI)
- Number of culture flasks/concentration: There were 29 bottles each prepared the blank, test sample, and reference substance (87 in total; 3 replicates for sampling once per week, and 5 on day 28). 11 bottles were prepared for the test sample + reference substance (3 replicates for day 1 and 56, and 5 on day 28).
- Method used to create aerobic conditions: During the experimental set-up, sludge was mixed, permitted to settle, and then kept in aerobic conditions.
- Measuring equipment: Shimadzu Carbon Analyzer (SHIMADZU); Multiparametric (pH, O2, temperature) (WTW); Infrared Gas Analyzer (NDIR).
- Test performed in open system: Glass bottles were sealed as part of a headspace test.

SAMPLING
- Sampling frequency: Days 0, 1, 7, 14, 21, 28, 35, 42, 49, and 56.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Untreated inoculum.
- Toxicity control: Test substance + reference substance.

Reference substance:

benzoic acid, sodium salt

Remarks:

Initial concentration: 19.05 mg/L TOC

Test performance:

The quality criteria of the test were satisfied. TIC in the blank control on day 56 was <3 mg C/L. The test sample + reference substance treatment confirmed a lack of an inhibitory effect of the test sample on the inoculum.

Parameter:

other: % degradation (TIC removal)

Value:

0

Sampling time:

0 d

Parameter:

other: % degradation (TIC removal)

Value:

4

Sampling time:

1 d

Parameter:

other: % degradation (TIC removal)

Value:

10

Sampling time:

7 d

Parameter:

other: % degradation (TIC removal)

Value:

6

Sampling time:

14 d

Parameter:

other: % degradation (TIC removal)

Value:

15

Sampling time:

21 d

Key result

Parameter:

other: % degradation (TIC removal)

Value:

17

Sampling time:

28 d

Parameter:

other: % degradation (TIC removal)

Value:

6

Sampling time:

35 d

Parameter:

other: % degradation (TIC removal)

Value:

3

Sampling time:

42 d

Parameter:

other: % degradation (TIC removal)

Value:

11

Sampling time:

49 d

Key result

Parameter:

other: % degradation (TIC removal)

Value:

9

Sampling time:

56 d

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

At the conclusion of a 56-day aerobic biodegradability experiment, Reaction products of stearic acid, diethylenetriamine and N-aminoethylethanolamine and acetic acid was determined not to be readily biodegradable (<60 % by day 28) (CLP Regulation (EC) No. 1272/2008).

Executive summary:

An experiment was undertaken to determine whether Reaction products of stearic acid, diethylenetriamine and N-aminoethylethanolamine and acetic acid, which is a substance of Unknown or Variable Composition, Complex Reaction Products and Biological Materials (UVCB), has the potential to be readily biodegradable under aerobic conditions. A 56-day test was performed according to Good Laboratory Practise (GLP) and OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test) without deviation. Liquid sewage (66 % urban and 34 % industrial) was obtained from a treatment plant for the purpose of the inoculum and a suitable culture medium prepared to be used in the blank (inoculum only), test sample, reference substance (sodium benzoate), and test sample + reference substance treatments. The initial nominal concentration for the test and reference substance was 18.81 and 19.05 mg/L of Total Organic Carbon (TOC), respectively. Total Inorganic Carbon (TIC) was measured on day 0, 1, 7, 14, 21, 28, 35, 42, 49, and 56 to determine percentage biodegradability.

The quality criteria of the experiment were satisfied. Percentage biodegradability on day 28 and at the termination of the experiment (day 56) was found to be 17 and 9 %, respectively. A UVCB substance is regarded as being readily biodegradable when its level of biodegradability is ≥60 % within a 28-day period (CLP Regulation (EC) No. 1272/2008). As the experimentally-derived values for biodegradability were <60 %, Reaction products of stearic acid, diethylenetriamine and N-aminoethylethanolamine and acetic acid was regarded as being non-readily biodegradable under the conditions of the test.

Description of key information

At the termination of a 56-day aerobic biodegradability experiment undertaken according to OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test), Reaction products of stearic acid, diethylenetriamine and N-aminoethylethanolamine and acetic acid was determined not to be readily biodegradable. Biodegradation of the test item was 17 % on day 28 and 9 % on day 56, the former of which is lower than the threshold of ≥60 % by day 28 specified under CLP Regulation (EC) No. 1272/2008.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater