N-[3-(dimethylamino)propyl] amides C18-22 (even numbered)

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Nov - 24 Dec 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-[3-(dimethylamino)propyl] amides C18-22 (even numbered)

IUPAC Name:

N-[3-(dimethylamino)propyl] amides C18-22 (even numbered)

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Cambridge Sewage Treatment Works, Cowley Road, collected 24 Nov 2009
- Pretreatment: Sieved to 850 µm, settled, decanted and resuspended using mineral media. Centrifuged at ca. 4000 rpm for ca. 10 minutes discarded the supernatant, re-suspended and centrifuged again at ca. 4000 rpm for ca. 10 minutes and discarded the supernatant. Dry sludge solids determination was conducted on the pellet produced
- Dry sludge solids: 5.7%
- Volume of mineral medium: 1.5 L per bioreactor
- Dry sludge solids in test: 0.03 g/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

> 39.4 - < 39.5 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

20 mg/L

Based on:

other: carbon

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST SYSTEM
- Culturing apparatus: 2000 mL flasks filled with 1500 mL test medium
- Number of culture flasks/concentration: 2
- Details of trap for CO2 and volatile organics if used: Atmospheric air was pumped into the test system and scrubbed clean of carbon dioxide by passing over soda lime. The air continued into the test vessel where it collets any evolved carbon dioxide before moving into the carbon dioxide traps, each containing 200 mL of 0.05 M sodium hydroxide solution
- Other: The test solutions were stirred for the duration of the study

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 flasks
- Reference: 2 flasks
- Toxicity control: 1 flask

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

0 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

24

Sampling time:

5 d

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

50

Sampling time:

9 d

% Degradation 4

Parameter:

% degradation (CO2 evolution)

Value:

71

Sampling time:

14 d

% Degradation 5

Parameter:

% degradation (CO2 evolution)

Value:

87

Sampling time:

28 d

Any other information on results incl. tables

Table 1: Inorganic carbon (mg) in 200 mL NaOH

Time (days)	Blank		Reference		Test chemical		Toxicity control
	1	2	1	2	1	2
2	2.52	2.54	10.82	9.24	4.01	3.44	14.00
5	2.17	2.06	8.17	8.09	9.25	7.21	13.17
7	1.13	1.05	3.49	3.73	5.35	5.03	6.23
9	0.94	0.80	2.76	2.81	4.10	5.84	5.38
14	1.62	1.48	4.54	5.44	6.97	8.77	9.85
19	0.85	0.84	2.49	2.61	3.73	3.78	5.12
23	0.63	0.51	2.00	2.14	2.17	2.29	3.81
28	1.24	0.59	1.42	2.06	1.26	1.46	2.15
29	0.65	1.84	1.69	2.30	1.17	0.33	1.48
29	2.56	1.47	3.13	2.44	1.60	1.24	6.33

Table 2: Cumulative inorganic carbon (mg) from test

Time (days)	Reference		Test chemical		Toxicity control
	1	2	1	2
0	0.00	0.00	0.00	0.00	0.00
2	8.29	6.71	1.48	0.91	10.27
5	14.34	12.68	8.61	6.00	15.21
7	16.74	15.32	12.87	9.94	16.25
9	18.63	17.26	16.10	13.91	17.16
14	21.62	21.15	21.52	21.13	19.14
19	23.26	22.91	24.40	24.06	20.50
23	24.69	24.48	26.00	25.78	22.08
28	25.19	25.62	26.34	26.32	22.87
29	25.63	26.67	26.26	25.40	23.60
29	26.74	27.09	25.84	24.62	28.51

Table 3: Percentage degradation

Time (days)	Reference			Test chemical			Toxicity control
	1	2	Mean	1	2	Mean
0	0	0	0	0	0	0	0
2	28	22	25	5	3	4	34
5	48	42	45	29	20	24	51
7	56	51	53	43	33	38	54
9	62	57	60	53	46	50	57
14	72	70	71	71	70	71	64
19	77	76	77	81	80	80	68
23	82	82	82	86	85	86	74
28	84	85	85	88	87	87	76
29	85	89	87	87	84	86	79
29	89	90	90	86	82	84	95

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable