2-Propenamide, 3-(1,3-benzodioxol-5-yl)-N,N-diphenyl-, (2E)-

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:

2016-01-20 to 2016-02-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2014-04-30

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: conventional treatment plant for domestic waste, Shenyang Northern Treatment Plant, China

- Preparation of inoculum for exposure: coarse particles were removed by filtration through a fine sieve and the sample was settled. After the supernatant was discarded, the sludge was washed twice with mineral medium and the concentrated sludge was suspended in mineral medium. 3 replicates of 10 ml suspended sludge were weighed and dried at 105°C for 125 min and reweighed to calculate the initial sludge concentration.

- Concentration of sludge: measured concentration of suspended sludge was 5.05 g/L as suspended solids (SS), which was adjusted to 4.04 g/L as suspended solids (SS). On the day of the test start, five replicates of 10 ml sludge were weighed and dried at 105°C for about 95 min and reweighed. The mean concentration of suspended sludge measured was 3806 mg/L SS.

- 7.880 mL of activated sludge was added to 1 L flask and made up to volume to give a suspended solid concentration of 30 mg/L.

- Storage length/ storage conditions: kept aerobic at 20.9-22.7°C until used for the test

Duration of test (contact time):

28 d

Initial conc.:

41.6 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
a) KH2PO4 (8.52 g/L), K2HPO4 (21.75 g/L), Na2HPO4 × 2H2O (33.40 g/L), NH4Cl (0.50 g/L)
b) CaCl2 (27.50 g/L)
c) MgSO4 × 7H2O (22.51 g/L)
d) FeCl3 × 6H2O (0.25 g/L)
- Test temperature: 22 °C +/- 1 °C
- pH: start of test: 7.49; end of test: 7.74 - 8.08
- Continuous darkness: diffuse light

TEST SYSTEM
- Culturing apparatus: 1-L flasks
- Number of culture flasks/concentration: 2 flasks each for test item and inoculum control; one flask each for procedure control and toxicity control
- Measuring equipment: oxygen uptake was measured in regular intervals by an automated respirometer (CES company)
- Incubation: 28 days under diffuse light

SAMPLING
- Sampling frequency: Oxygen uptake was recorded by an automated respirometer in all test flasks at 24 hour intervals for 28 days. Evolved CO2 was absorbed in a solution of sodium hydroxide.
- The pH of various test solutions was measured at the end of the incubation period on Day 28.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 replicates, containing only inoculum)
- Toxicity control: yes (1 replicate; 41.8 mg/L test substance; equivalent to 93.6 mg/L ThOD and 55.7 mg/L reference substance; equivalent to 93.0 mg/L ThOD resulting in total ThOD of 186.6 mg/L)
- Procedure control: yes (1 replicate; 56.9 mg/L reference substance; equivalent to 95.0 mg/L ThOD)

Reference substance:

benzoic acid, sodium salt

Remarks:

Purity: 99.6 %; 56.9 mg/L medium

Preliminary study:

not applicable

Test performance:

No unusual observation during tests.

Key result

Parameter:

% degradation (O2 consumption)

Value:

1.6

Sampling time:

28 d

Details on results:

The main biodegradation of test item after 28 days amounts to 1.6 % (2 replicates).

Biodegradation of the reference substance (Sodium benzoate): 63.5, 87.7 and 92.9 % after Day 4, 14 and 28, respectively.

Toxicity Control: 44.2 % degradation within 14 days exceeding 25 % based on total ThOD indicating that the test item is not inhibitory under the test conditions.

In conclusion, according to the guideline, the test item is not readily biodegradable under the test conditions.

Validity: The test is valid, as
- the difference between extremes of replicates of the removal of the test item at the plateau and at test end was less than 20 %,
- the percentage degradation of the reference substance (with 87.7 %) exceeded pass level of 60 % by day 14,
- 44.2 % and thus more than 25 % degradation based on total ThOD occured in toxicity control within 14 days,
- the oxygen uptake of the inoculum blank was 22.0 mg O2/L and thus < 60 mg/L in 28 days, and
- the pH remained within the range of 6.0 - 8.5.

Results with reference substance:

The reference substance sodium benzoate degraded up to 87.7 % within the first 14 days.

Table 1 Biodegradation Results of Test Item (28 days)

	02 -uptake (mg 02/L)					BOD (mgO2/mg test item)			Biodegradation
Day	IC-1	IC-2	TS-1	TS-2	IC Average	TS-1	TS-2	TS Average	TS-1	TS-2	TS Average
1	2.29	2.79	2.83	3.25	2.5	0.008	0.018	0.013	0.4%	0.8%	0.6%
2	4.44	5.04	4.85	5.79	4.7	0.004	0.026	0.015	0.2%	1.2%	0.7%
3	6.29	6.85	7.08	8.12	6.6	0.012	0.037	0.025	0.5%	1.7%	1.1%
4	8.06	8.60	8.70	10.18	8.3	0.010	0.045	0,028	0.4%	2.0%	1.2%
5	9.91	10.35	10.35	12.08	10.1	0.006	0.048	0.027	0.3%	2.1%	1.2%
6	11.12	11.54	11.47	13.41	11.3	0.004	0.051	0.028	0.2%	2.3%	1.3%
7	11.45	11.93	11.95	13.97	11.7	0.006	0.055	0.031	0.3%	2.5%	1.4%
8	12.00	12.83	12.74	14.97	12.4	0.008	0.062	0.035	0.4%	2.8%	1.6%
9	12.43	13.24	13.16	15.76	12.8	0.009	0.071	0.040	0.4%	3.2%	1.8%
10	13.04	13.85	13.79	16.64	13.4	0.009	0.078	0.044	0.4%	3.5%	2.0%
11	13.62	14.37	14.41	17.35	14.0	0.010	0.080	0.045	0.4%	3.6%	2.0%
12	14.20	14.89	15.10	18.03	14.5	0.014	0.085	0.050	0.6%	3.8%	2.2%
13	15.20	15.66	15.68	19.01	15.4	0.007	0.087	0.047	0.3%	3.9%	2.1%
14	15.76	16.29	16.39	19.62	16.0	0.009	0.087	0.048	0.4%	3.9%	2.2%
15	16.06	16.45	16.39	19.89	16.3	0.002	0.086	0.044	0.1%	3.8%	2.0%
16	16.33	16.74	16.60	20.30	16.5	0.002	0.091	0.047	0.1%	4.1%	2.1%
17	16.95	17.45	17.14	20.93	17.2	0.000	0.090	0.045	0.0%	4.0%	2.0%
18	17.37	17.93	17.58	21.43	17.7	0.000	0.090	0.045	0.0%	4.0%	2.0%
19	17.64	18.37	17.87	21.80	18.0	0.000	0.091	0.046	0.0%	4.1%	2.1%
20	18.12	18.97	18.26	22.26	18.5	0.000	0.090	0.045	0.0%	4.0%	2.0%
21	18.72	19.60	18.66	22.78	19.2	0.000	0.086	0.043	0.0%	3.8%	1.9%
22	19.16	20.10	19.10	23.12	19.6	0.000	0.085	0.043	0.0%	3.8%	1.9%
23	19.53	20.41	19.26	23.30	20.0	0.000	0.079	0.040	0.0%	3.5%	1.8%
24	19.62	20.66	19.89	24.03	20.1	0.000	0.094	0.047	0.0%	4.2%	2.1%
25	20.62	21.20	20.14	24.22	20.9	0.000	0.080	0.040	0.0%	3.6%	1.8%
26	20.80	21.32	20.33	24.28	21.1	0.000	0.076	0.038	0.0%	3.4%	1.7%
27	21.53	21.78	20.64	24.62	21.7	0.000	0.070	0.035	0.0%	3.1%	1.6%
28	21.87	22.10	21.03	24.93	22.0	0.000	0.070	0.035	0.0%	3.1%	1.6%

Note: IC = Incentum Control; TS = Test Suspension.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not biodegradable after 28 days of exposure under conditions of the Manometric Respirometry Test (OECD 301 F). Further, 41.8 mg/L of the substance did not inhibit the biodegradataion of the reference substance sodium benzoate.

Description of key information

Biodegradation in water - manometric respirometry test (OECD 301F; GLP compliant): not readily biodegradable (1.6 % after 28 days)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

One GLP study on biodegradation (OECD 301F) was conducted with non-adapted activated sludge. The manometric respirometry test resulted in 1.6 % degradation of the substance after 28 days. Hence, the substance is not readily biodegradable under the test conditions. Further, the test item did not inhibit the activity of activated sludge microorganisms at 41.8 mg/L (biodegradation in toxicity control was ≥ 25 % after 14 days of incubation). The biodegradation of the reference substance sodium benzoate (56.9 mg/L) amounted to 87.7 % after 14 days.