N,N-dimethyl-3-(octadecyloxy)propylamine

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

Study period:

From 13 July to 16 August 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

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.
The activated sewage sludge sample was washed three times by settlement and resuspension in culture medium to remove any excessive amount of dissolved organic carbon (DOC) that may have been present.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

-Preparation of inoculum
The activated sewage sludge sample was washed three times by settlement and resuspension in culture medium to remove any excessive amount of dissolved organic carbon (DOC) that may have been present.

-Preparation of 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.
b) The standard material (sodium benzoate), in duplicate, in inoculated culture medium to give a final concentration of 10 mg carbon/l.
c) The test material, in duplicate, in inoculated culture medium to give a final concentration of 10 mg carbon/l.
d) The test material 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).

Each test vessel was inoculated with the prepared inoculum at a final concentration of 30 mg suspended solid (ss)/l. The test was carried out in a temperature controlled room at approximately 21ºC, in darkness.

Approximately 24 hours prior to addition of the test and standard materials the vessels were filled with 2400 ml of culture medium and 22.5 ml of 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 though a glass column containing self-indicating soda lime granules.

The CO2 produced by degradation was collected in two 500 ml Dreschel bottles containing 350 ml of 0.05 M NaOH. The CO2 absorbing solutions were prepared using purified de-gassed water.

-Calculation of carbon content
The test material contains 77.2% carbon (data supplied by the sponsor) and so far a concentration of 10 mg C/l (a total of 39.0 mg of test material in 3 litres) the total organic carbon present was 30 mg C.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

Results obtained from the samples taken for DOC analysis from the preliminary investigational work indicated that the test material did adsorb to filter matrices but did not adsorb to activated sewage sludge, For the purpose of the study, the samples taken for DOC analysis were centrifuged to remove the suspended solids present without the loss of any test material.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

22

Sampling time:

28 d

Parameter:

% degradation (DOC removal)

Value:

38

Sampling time:

28 d

Details on results:

The test material attained 22% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

The toxicity control attained 74% degradation after 14 days and 70% degradation after 28 days thereby confirming that the test material was not toxic to the sewage treatment micro-organisms used in the test. The decrease in degradation obtained for the toxicity control between Day 14 and Day 28 was considered to be due to a slightly greater increase in CO2 evolution values in the control inorganic carbon values compared to the increase in inorganic carbon within the toxicity control vessel during this time period.

Sodium benzoate attained 66% degradation after 14 days and 90% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Analysis of the test media from the test material culture vessels on Days 0 and 28 for Dissolved Organic Carbon (DOC) gave percentage degradation values of 37% and 38% respectively for the test material Replicates R1 and R2 and 75% for the toxicity control. Sodium benzoate attained 99% and 98% degradation respectively for Replicates R1 and R2 calculated from the results of the DOC analyses. The degradation rates calculated from the results of the DOC analyses were higher than those calculated from inorganic carbon analysis. This was considered to be due to incorporation of test material/sodium benzoate into the microbial biomass prior to degradation, and hence CO2 evolution occurring.

Percentage Biodegradation Values

*Day 29 values corrected to include any carry-over of CO2 detected in Absorber 2

Day	% Degradation Sodium Benzoate	% Degradation Test Material	% Degradation Test Material plus Sodium Benzoate Toxicity Control
0	0	0	0
1	5	0	2
2	14	0	19
3	23	0	26
6	38	1	48
8	50	6	61
10	64	18	63
14	66	24	74
16	66	27	72
20	86	23	69
22	93	20	67
24	88	20	69
27	75	18	67
28	90	21	71
29*	90	22	70

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test material attained 22% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

Executive summary:

The study was performed to assess the ready biodegradability of the test material in aerobic aqueous medium. The method followed that described in the OECD Guidelines No 301B.

 

The test material, at a concentration of 10 mg Carbon/l, was exposed to activated sewage sludge micro-organisms with culture medium in sealed culture vessels in the dark at approximately 21ºC 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 22% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 18, 2001 to December 5, 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

The inoculum was fresh samples collected from no fewer than ten sites, such as sewage treatment works, industrial waste-water treatment works, rivers, lakes, seas, sludge, surface soil, water etc. It was purchased from Chemicals Evaluation and Research Institute Japan on October 18th, 2001. The conditions of the inoculum were as follows (on the day of initiation of the study).

Temperature: 25.1°C
Dissolved Oxygen: 7.7 mg/L
pH: 7.9
Suspended Solids: 4542 mg/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

PREPARATION OF TEST SOLUTIONS
(1) Abiotic control: 300 ml of distilled water with 30.0 mg of test substance, N=1
(2) Test item: 300 ml of mineral medium with 30.0 mg of test substance and inoculum (30 mg/L SS), N=3
(3) Positive control: 300 ml of mineral medium with 30.0 mg of aniline and inoculum (30 mg/L SS), N=1
(4) Inoculum control: 300 ml of mineral medium with inoculum (30 mg/L SS), N=1

TEST SYSTEM
-Temperature was 25±1°C
-Analysis was conducted on day 28.
-Oxygen consumption was measured daily.
-Observation of test solutions was conducted daily.
-pH was measured both on the initial day and the final day of the incubation.

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

38.3

Sampling time:

28 d

Key result

Parameter:

% degradation (DOC removal)

Value:

83.6

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

99.7

Sampling time:

28 d

Details on results:

The degradation results based on BOD, DOC and chemical analysis were 38.3%, 83.6%, and 99.7%, respectively (average). The GC chemical analysis showed that neither test material nor metabolites remained in the test system. However, DOC results indicated that 16% of soluble metabolites were produced. Even at the end of the study, BOD curve was still increasing, suggesting that the biodegradation of organic material was still on going. Thus, it was assumed that the remaining metabolites would be biodegraded completely as the time went by. Therefore it was concluded that the test substance was biodegradable.

Results with reference substance:

The biodegradation of aniline was 61.0% after 7 days, and 65.3% after 14 days, confirming the validity of this study.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The study showed that the test substance was biodegradable.

Executive summary:

The degradation results based on BOD, DOC and chemical analysis were 38.3%, 83.6%, and 99.7%, respectively (average). The GC chemical analysis showed that neither test material nor metabolites remained in the test system. However, DOC results indicated that 16% of soluble metabolites were produced. Even at the end of the study, BOD curve was still increasing, suggesting that the biodegradation of organic material was still on going. Thus, it was assumed that the remaining metabolites would be biodegraded completely as the time went by. Therefore it was concluded that the test substance was biodegradable.

Reference 3

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 18, 2001 to December 12, 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

The inoculum was fresh samples collected from no fewer than ten sites, such as sewage treatment works, industrial waste-water treatment works, rivers, lakes, seas, sludge, surface soil, water etc. It was purchased from Chemicals Evaluation and Research Institute Japan on October 18th, 2001. The conditions of the inoculum were as follows (on the day of initiation of the study).

Temperature: 25.0°C
Dissolved Oxygen: 7.7 mg/L
pH: 7.7
Suspended Solids: 4377 mg/L

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

PREPARATION OF TEST SOLUTIONS
(1) Abiotic control: 300 ml of distilled water with 9.0 mg of test substance, N=1
(2) Test item: 300 ml of mineral medium with 9.0 mg of test substance and inoculum (100 mg/L SS), N=3
(3) Positive control: 300 ml of mineral medium with 30.0 mg of aniline and inoculum (30 mg/L SS), N=1
(4) Inoculum control: 300 ml of mineral medium with inoculum (100 mg/L SS), N=1

TEST SYSTEM
-Temperature was 25±1°C
-Analysis was conducted on day 28.
-Oxygen consumption was measured daily.
-Observation of test solutions was conducted daily.
-pH was measured both on the initial day and the final day of the incubation.

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

69.2

Sampling time:

28 d

Remarks on result:

other: % degradation reached 81.3% on day 20

Key result

Parameter:

% degradation (DOC removal)

Value:

98.6

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

100

Sampling time:

28 d

Details on results:

The degradation results based on BOD, DOC and chemical analysis were 69.2%, 98.6%, and 100.0%, respectively (average). The degradation based on BOD reached 81.3% (average) on day 20, however, the degradation rate decreased to 69.2% on day 28. It was assumed that the oxygen consumption stopped in test items after day 20, on the other hand in the inoculum control, the oxygen consumption kept going until the end of the study, leading the decrease of the degradation rate.

The GC chemical analysis showed that neither test material nor metabolites remained in the test system. Besides DOC results indicated that most of the organic materials removed from the test system. These findings suggest that the test substance and its metabolites were completely biodegraded. Therefore it was concluded that the test substance was inherently biodegradable.

Results with reference substance:

The biodegradation of aniline was 60.4% after 7 days, and 66.3% after 14days, confirming the validity of this study.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The study showed the test substance and its metabolites were completely biodegraded. Therefore it was concluded that the test substance was inherently biodegradable.

Executive summary:

The degradation results based on BOD, DOC and chemical analysis were 69.2%, 98.6%, and 100.0%, respectively (average). The degradation based on BOD reached 81.3% (average) on day 20, however, the degradation rate decreased to 69.2% on day 28. It was assumed that the oxygen consumption stopped in test items after day 20, on the other hand in the inoculum control, the oxygen consumption kept going until the end of the study, leading the decrease of the degradation rate.

The GC chemical analysis showed that neither test material nor metabolites remained in the test system. Besides DOC results indicated that most of the organic materials removed from the test system. These findings suggest that the test substance and its metabolites were completely biodegraded. Therefore it was concluded that the test substance was inherently biodegradable.

Description of key information

Three studies are available to assess the biodegradation. Two ready biodegradation study results indicated that the test substance failed to pass the criteria of ready biodegradation. However they suggested the test substance was biodegradable.

 

The key study was conducted according to OECD Guideline 302C. The degradation results based on BOD, DOC and chemical analysis were 69.2%, 98.6%, and 100.0%, respectively. However the degradation based on BOD reached 81.3% on day 20. These findings indicate that the test substance as well as its metabolites were completely biodegraded. According to the OECD guidelines, Section 3 introduction, Inherent biodegradability test (2006), biodegradation above 70% of theoretical may be regarded as evidence of inherent, ultimate biodegradability. The results both based on the BOD and DOC pass the criteria. Therefore, the registered substance should be considered to be inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable