Fatty acids, C18-unsatd., dimers, hydrogenated, reaction products with N1,N1-dimethyl-1,3-propanediamine

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:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study; well documented study report

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-bis[3-(dimethylamino)propyl]-9-nonyl-10-octylnonadecanediamide; N-[3-(dimethylamino)propyl]-9-[2-(7-{[3-(dimethylamino)propyl]carbamoyl}heptyl)-3-[(2E)-oct-2-en-1-yl]-4-pentylcyclohexyl]nonanamide; N-[3-(dimethylamino)propyl]-9-[2-(7-{[3-(dimethylamino)propyl]carbamoyl}heptyl)-3-octyl-4-pentylcyclohexyl]nonanamide

EC Number:

937-688-5

Cas Number:

1391530-05-4

Molecular formula:

C46H82N4O2 to C46H94N4O2

IUPAC Name:

N,N'-bis[3-(dimethylamino)propyl]-9-nonyl-10-octylnonadecanediamide; N-[3-(dimethylamino)propyl]-9-[2-(7-{[3-(dimethylamino)propyl]carbamoyl}heptyl)-3-[(2E)-oct-2-en-1-yl]-4-pentylcyclohexyl]nonanamide; N-[3-(dimethylamino)propyl]-9-[2-(7-{[3-(dimethylamino)propyl]carbamoyl}heptyl)-3-octyl-4-pentylcyclohexyl]nonanamide

Details on test material:

- Physical state: amber coloured viscous liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Source:
A mixed population of activated sewage sludge micro-organisms was obtained from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire UK, which treats predominantly domestic sewage.

Culture medium: The culture medium used in this study was that recommended in the OECD guidelines.

Preparation:
The activated sewage sludge sample was washed three times by settlement and resuspension in culture medium to remove any excessive amounts of dissolved organic carbon that may have been present. The washed sample was then maintained on continuous aeration in the laboratory at a temperature of 21 degrees C and used on the day of collection. Determination of the suspended solids level of the activated sewage sludge was carried out by filtering a sample of the washed activated sewage sludge by suction through pre-weighed GF/A filter paper using a Buchner funnel. Filtration was then continued for a further 3 minutes after sensing the filter three successive times with 10 ml of deionised reverse osmosis water. The filter paper was then dried in an oven at approximately 105 degrees C for at least 1 hour and allowed to cool before weighing. This process was repeated until a constant weight was attained.

Concentration:
The suspended solids concentration was equal to 3.3 g/l prior to use.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 other: mg/L carbon

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Pre-Study Solubility Work
Pre-study solubility work was conducted by ultrasonication and high shear mixing. This work confirmed that the test material was poorly soluble. Additional solubility work was conducted to ascertain the method that would give the best testable dispersion. This work concluded that it was appropriate to dissolve the test material in solvent prior to coating the silica gel with the solvent test material stock solution and then removing the solvent as this method appeared to increase the dispersibility of the test material over the other methods investigated.

TEST SYSTEM
-The following test preparations were prepared and inoculated in 5 litre glass culture vessels each containing 3 litres of solution:
a) A control, in duplicate, consisting of inoculated culture medium plus silic gel
b) The standard material (sodium benzoate) in duplicate in inoculated culture medium plus silic gel to give a final concentration of 10 mg carbon/l.
c) The test material dissolved in acetone coated on silica gel in duplicate in inoculated culture medium to give a final concentration of 10 mg carbon/l.
d) The test material dissolved in acetone coated on silic gel plus the standard material in inoculated culture medium to give a final concentration of 20 mg carbon/l to act as a toxicity control (one vessel only).

-Silica gel was added to the control and standard material vessels in order to maintain consistency between these vessels and the test material vessels. Each test vessel was inoculated with the prepared inoculum at a final concentration of 30 mg suspended solids per liter. The test was carried out in a temperature controlled room at 21 degrees C in darkness.

-Approximately 24 hours prior to addition of the test and standard materials the vessels were filled with culture medium and inoculum and aerated overnight. On Day 0 the test and standard materials were added and the volume in all the vessels adjusted to 3 litres by the addition of culture medium The culture vessels were sealed and CO2 free air bubbled through the solution at a rate of approximately 40 ml/minute and stirred continuously by magnetic stirrer. The CO2 free air was produced by passing compressed air through a glass column containing self indicating soda lime granules.

-The CO2 produced by degradation was collected in Dreschel bottles containing sodium hydroxide. The CO2 absorbing solutions were prepared using purified degassed water.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

17

Sampling time:

28 d

Details on results:

The test material attained 17% degradation after 28 days. The toxicity control attained 46% degradation after 14 days. Sodium benzoate attained 109% degradation after 14 days and 93% degradation after 28 days. Observations made on Day 0 of the test period showed the contents of the control vessels to be light brown dispersions and the contents of the standard material vessels were light brown dispersions with no undissolved standard material visible. The test material vessels were observed to be light brown dispersions with no undissolved test material visible. The toxicity control vessel contained a light brown dispersion with no undissolved test or standard material visible.

BOD5 / COD results

Results with reference substance:

Sodium benzoate attained 109% degradation after 14 days and 93% degradation after 28 days

Any other information on results incl. tables

Percentage Biodegradation Values

Day	% Degradation Sodium Benzoate	% Degradation Test Material	% Degradation Test Material plus Sodium Benzoate; Toxicity Control
0	0	0	0
2	25	0	19
6	74	17	56
8	64	18	55
10	103	11	44
14	109	15	46
21	100	23	NA
28	91	26	NA
29	93	17	NA

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: Not Readily Biodegradable under Test Conditions

Conclusions:

The test material attained 17% degradation after 28 days. The reference substance attained 93% degradation after 28 days

Executive summary:

The objective of the study was to measure the amount of carbon dioxide produced from the biodegradation of the test substance under the conditions tested. The study was conducted according to procedures specified by the OECD Guideline for Testing of Chemicals, Method 301B, EEC Method C.4-C, and US EPA Guideline OPPTS 835.3110.

In view of the difficulties associated with the evaluation of the biodegradability of organic compounds with low water solubility a modification to the standard method of preparation of the test concentration was performed. An approach endorsed by the International Standards Organisation and the published literature is to dissolve the test material in an auxiliary solvent prior to adsorption onto granular silica gel. Using this method the test material is evenly distributed throughout the test medium and the surface area of the test material exposed to the test organisms is expected to increase.

 

The test material at a concentration of 10 mg carbon per liter was exposed to activated sewage sludge microbes with culture medium in sealed culture vessels in the dark at approximately 21 degrees C for 28 days.

 

The degradation of the test material was assessed by the determination of carbon dioxide produced. Control solutions with inoculum and the standard material, sodium benzoate, together with a toxicity control were used for validation purposes.

 

The test material attained 17% degradation after 28 days and therefore cannot be considered to be readily biodegradation under the conditions of the test and under the strict terms and conditions of OECD Guideline 301B.