(Z)-N-octadec-9-enylhexadecan-1-amide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: Biodegradation; Repetitive Die Away Test, DGXI/400/84, Rev1; European Economic Communities, 1984

Principles of method if other than guideline:

The RDA (Repetitive Die Away) test is used, because according to De Morsier et al. (1987), this method is suitable for poorly-soluble substances.

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, non-adapted

Details on inoculum:

Closed bottle test:
- Source of inoculum/activated sludge: The inoculum is an industrial activated sludge from Unichemia Chemie, Gouda.
- Pretreatment: The sludge is preconditioned during a week, to reduce high residual respiration rates. The density of the inoculum is 32 mg s.s./L.

Duration of test (contact time):

6 wk

Initial conc.:

40 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: According to guideline but without ammonia. This modification is introduced to minimize the consumption of the dilution water and analyses.
- Solubilising agent: Genapol PF-40 (Hoechst), 10% of the weight of the test material and nonylphenol+10 EO+ 5 PO, 20% of the weight of the test material (according to De Morsier et al., 1987)

TEST SYSTEM
- Number of culture flasks/concentration: 3

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: vehicle control

Parameter:

% degradation (O2 consumption)

Value:

16

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

21

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

27

Sampling time:

42 d

Since the emulsifier showed to be slightly biodegradable in the Closed Bottle test, they were also tested in the RDA-test, separately as well as combined. Again some oxygen consumption was observed in some cases, but this was not consistent in time. Moreover, the oxygen consumption of combined emulsifier reference (Gen + non) did not account tor the oxygen consumption of the separate samples (Genapol; nonyl phenol). lt is concluded that small differences cannot be detected with accuracy. Therefore, no attempt is made tor correction, although lt should be kept in mind that the following biodegradation percentages in industrial sludge may be overestimated tor week 6: 16% after 2 weeks, 21% after 4 weeks, and 27% after 6 weeks.

The slow linear increase in the percentage biodegradation may be explained by the limited bioavailability of the test substance, due to the poor water-solubility.

Biodegradability test with industrial sludge:

week		pH	oxygen concentration mg 02/L 3 replicates	mean	C-C,D mg 02/L
1	blanc control (NaAc) Genapol  nonyl phenol Gen + non oleyl palmitamide	7.4 7.3 7.3 7.4 7.4 7.3	8.43 8.49 8.56 4.67 4.81 5.00 8.45 8.43 8.47 8.47 8.52 8.51 8.28 8.39. 8.33 8.06 7.95 7.57	8.49 4.83 6.45 8.50 8.33 7.86	3.36 0.04 -0.01 0.16 0.63
2	blanc control (NaAc) Genapol  nonyl phenol Gen + non oleyl pamitamide	7.3 7.4 7.3 7.3 7.3 7.1	8.87 8.62 9.05 8.42 8.32 8.04 8.81 8.63 8.54 8.65 8.49 8.63 8.75 8.37 8.45 8.49 8.09 7.48	8.85 8.26 8.66 8.59 8.52 8.02	0.59 0.19 0.26 0.33 0.83
4	blanc control (NaAc) Genapol  nonyl phenol Gen + non oleyl pamitamide	7.4 7.5 7.4 7.4 7.5 7.3	8.90 8.82 8.80 8.24 8.31 8.29 8.83 8.80 8.82 8.83 8.83 8.78 9.00 8.88 8.81 8.35 8.49 8.23	8.84 8.28 8.82 8.81 8.90 8.36	0.56 0.02 0.03 -0.06 0.48
6	blanc control (NaAc) Genapol  nonyl phenol Gen + non oleyl pamitamide	7.4 7.6 7.3 7.3 7.4 7.3	9.27 9.20 9.00 8.89 8.64 8.74 8.92 8.82 8.65 8.90 8.80 8.82 8.90 8.90 8.79 8.81 8.54 8.68	9.16 8.76 8.80 8.84 8.86 8.68	0.40 0.36 0.32. 0.30 0.48

The test was performed with 7.86 mg substance per bottle. Each bottle contained 0.92 mg nonyl phenol and 0.40 mg Genapol.

The reference Genapol contained 0.46 mg/bottle.

The reference nonyl phenol contained 0.94 mg/bottle.

The reference gen + non contained 0.46 mg Genapol and 0.94 mg nonyl phenol/bottle.

The control (NaAc) contained 42 mg with a ThOD of 18.33 mg 02/bottle.

 

Toxicity control for RDA Test, industrial sludge. Exposition time: 8 days.

	pH	oxygen concentration mg 02/L 3 replicates	mean	Ct – Cb mg 02/L	inhibition %
Blanc NaAc   NaAC+ oleyl palmitamide 42 mg/L	7.4 7.3     7.2	8.43 8.49 8.56 4.67 4.81 5.00     4.18 4.22 4.43	8.49 4.83      4.28	3 . 66     4.21	0

 

Interpretation of results:

other: not readily biodegradable

Reference 2

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: GLP Guideline study with acceptable restrictions (only 3 measurements)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

, modification of medium (recommendations of Block et al, 1985), only 3 measurements

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Closed bottle test:
- Source of inoculum/activated sludge: Municipal waste water treatment plant in Duiven, The Netherlands
- Pretreatment: The sludge is preconditioned: a sludge suspension of 1 g s.s./L is aerated during 3 days, to reduce high residual respiration rates.
- Concentration of sludge: 3 mg s.s./L

Duration of test (contact time):

6 wk

Initial conc.:

2.06 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline but without ammonia. This modification is introduced to minimize
- Solubilising agent: Genapol PF-40 (Hoechst), 10% of the weight of the test material and nonylphenol+10 EO+ 5 PO, 20% of the weight of the test material (according to De Morsier et al., 1987)

TEST SYSTEM
- Number of culture flasks/concentration: 3

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: vehicle control

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

14

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

27

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

30

Sampling time:

42 d

Biodegradability test with domestic sludge:

week		pH	oxygen concentration mg 02/L 3 replicates	mean	C-C,D mg 02/L	biodegradation BOD/COD (%)
2	blanc control (NaAc) emulsifier oley palmitamide	7.0 6.9 7.1 6.8	7.42 7.43 7.19 1.74 1.99 1.72 7.40 7.20 7.30 6.31 6.14 6.30	7.35 1.82 7.30 6.25	5.53 0.05 1.10	5.53/6.86= 81 1.05*/7.25= 14
4	blanc control (NaAc) emulsifier oley palmitamide	7.0 6.9 7.0 6.9	6.73 6.70 6.99 1.12 0.98 1.22 6.70 6.85 6.40 4.74 4.60 4.72	6.81 1.11 6.65 4.69	5.70 0.18 2.12	5.70/6.85= 83 1.96*/7.25= 27
6	blanc control (NaAc) emulsifier oley palmitamide	7.1 6.9 7.0 6.9	6.70 6.76 6.83 0.82 1.18 0.80 6.30 6.25 6.50 4.40 4.23 4.07	6.76 0.93 6.35 4.23	5.83 0.41 2.53	5.83/6.86= 85 2.16*/7.25= 30

* correction for degradation of emulsifiers

The test medium contained per liter 2.06 mg oleyl palmitamide, 0.69 mg nonyl phenol 10E05P0 and 0.33 mg Genapol PF40.

The COD was 2.06 * 3.52= 7.25 mg/l (T47 p. 45).

The emulsifier reference did show some biodegradation. Therefore, a correction was made as follows:

The emulsifier reference contained 0.76 mg nonyl phenol and 0.38 mg Genapol/L. The sample emulsion contained 0.69 mg nonyl phenol/L at the most. The oxygen consumption in the sample due to the emulsifier is 0.69/0.76= 91% of the oxygen consumed in the emulsifier reference, resulting in week 2: 0.05 * 91%= 0.05, and the corrected BOD is 1.10 — 0.05= 1.05; in week 4: 0.18 * 91% 0.16, the corrected BOD is 2.12 - 0.16= 1.96; and in week 6: 0.41 * 91%= 0.37, the corrected BOD is 2.53 - 0.37= 2.16.

Toxicity control for Closed Bottle Test, domestic sludge. Exposition time: 8 days.

	pH	oxygen concentration mg 02/L 3 replicates	mean	Ct – Cb mg 02/L	inhibition %
oleyl palmitamide 2.1 mg/1 6.2 mg/1	6.8 6.7	2.32 2.32 2.30 1.17 1.56 2.08	2.31 1.60	5.72 6.43	0 0

Interpretation of results:

other: not readily biodegradable

Description of key information

 Two studies investigating the ready biodegradability of (Z)-N-octadec-9-enylhexadecan-1-amide (CAS No. 16260-09-6) are available. These studies were conducted according to the OECD Guideline No. 301D and Repetitive Die Away Test. The OECD Guideline No. 301D is the key study and the biodegradation reached a maximum of 27% biodegradation after 28 d (30% after 42 d). The Repetitive Die Away Test is considered as supportive study because the study is performed with activated industrial sludge. The biodegradation reached a maximum of 21% biodegradation after 28 d (27% after 42 d). Therefore, the substance is considered as not readilybiodegradable.
    

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The ready biodegradability of (Z)-N-Octadec-9-enylhexadecan-1-amide (CAS No. 16260-09-6) was investigated in one GLP-study comprising a test according to OECD guideline 301 D and a repetitive die away test following DGXI/400/84, EEC 1984 (Balk and Hantink-de Rooij, 1989). In the OECD closed bottle test 2.06 mg/L of the substance was incubated with domestic activated sludge for 6 weeks. The substance reached 27% degradation after 27 days and 42% degradation after 30 days. In the die away test 40 mg/L of the substance was incubated with industrial non-adapted activated sludge as inoculum over 6 weeks. Degradation rates were 21% after 21 days and 27% after 42 days. Hence, the substance is considered to be not readily biodegradable.