Hexadecylamine

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:

weight of evidence

Study period:

July - August 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

no analytics, no purity

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

yes

Remarks:

no analytics, no purity

Qualifier:

equivalent or similar to guideline

Guideline:

ISO DIS 9408 (Ultimate Aerobic Biodegradability - Method by Determining the Oxygen Demand in a Closed Respirometer)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge : domestic sewage treatment plant Frankfurt am Main, Sindlingen
- Concentration of sludge: 13.5 mL/L (wet sludge); 30 mg/L (dry weight)

Duration of test (contact time):

28 d

Initial conc.:

127.1 mg/L

Based on:

test mat.

Initial conc.:

126.5 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
- Test temperature: 20 +/- 1°C

TEST SYSTEM
- Culturing apparatus: BOD glass bottles
- Number of culture flasks/concentration: 2
- Measuring equipment: manometric determination of oxygen consumption

SAMPLING
- Sampling frequency: day 7, 14, 21, 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Reference control: yes

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

26

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

50

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

65

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Details on results:

The mean of the % biodegraded test substance in the test vessels with test substrate is 65% in 21 days and 70% in 28 days. The difference between the replicates is 12% at day 28. The adaption phase until 10% degradation of the test substance occured was less than 7 days. Within the 10-day window after adaption the biodegradation was ca. 50%.

Results with reference substance:

More than 60% of the reference substance was degraded in less than 10 days. After 7 days the referenc substance was 83% degraded.

Table 1: O₂measurements with blank control (BKtr)

Time	7 d	14 d	21 d	28 d
BKtr A	20 mg/L	35 mg/L	40 mg/L	50 mg/L
BKtr B	15 mg/L	20 mg/L	25 mg/L	30 mg/L
BKtr C	10 mg/L	15 mg/L	20 mg/L	20 mg/L
BKtr Mean	15 mg/L	23 mg/L	28 mg/L	33 mg/L

 

 

Table 2: O₂measurements bottles with test substance

Time	7 d	14 d	21 d	28 d
A	145 mg/L	235 mg/L	325 mg/L	360 mg/L
B	115 mg/L	245 mg/L	300 mg/L	320 mg/L
A – BKtr Mean	130 mg/L	212 mg/L	297 mg/L	327 mg/L
B – BKtr Mean	100 mg/L	222 mg/L	272 mg/L	287 mg/L
A in %	30 (32) %	48 (52) %	68 (73) %	75 (80) %
B in %	23 (25) %	51 (55) %	62 (67) %	66 (71) %
Mean % degradation	26 (28) %	50 (53) %	65 (70) %	70 (76) %

The degradation calculation in % is based on thBOD with N-oxidation.

In brackets: Calculation results based on thCOD without N-oxidation.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The ready biodegradability of the test substance in the respirometric method (OECD 301F) was assessed. The substance is not readily biodegradable but failing the 10d window.

Executive summary:

The ready biodegradability of the test substance in the respirometric method (OECD 301F) was assessed with a non-adapted activated sludge over a period of 28 days. The test substance was tested in a concentration of 127 mg/L in duplicates. The biological degradation of the test substance was followed by manometric determination of the oxygen consumption. In order to check the activity of the study system sodium benzoate was used as positive control. It was degraded to 83 % after 7 days and therefore the quality criteria of "degradation > 60 % after 14 days” was fulfilled. In the 10-day window the test substance came to a mean degradation rate of 50 %. After 28 days a mean degradation rate of 70 % was reached. The test substance is not readily biodegradable because of failing the 10 d window. During the test no determination of nitrogen was assessed, which could possibly alter the result.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

January - March 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

no data on purity, no analytics

Principles of method if other than guideline:

In the inoculum less colony forming units than recomended.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant at Hildesheim
- Prereatment: The activated sludge is maintained in an aerobic condition by aeration for four hours and then homogenized with a mixer. The sludge is filtered and the filtrate is subsequently used to initiate inoculation.
- Colony forming units of the inoculum: ca. 18x10^4 (CFU/mL)
- Colony forming units in the test vessels: ca. 18x10^2 (CFU/mL)
The guideline recommends the range of colony forming units between 10^6 and 10^8 (colony forming units/mL). Chosen was a bacterial density, which in experience quickly adapted considering the biodegradation of the ready biodegradable functional control, which is tested usually in each test series. Also the test duration of 28 days allows sufficient time for adaptation of the microorganisms to the test compounds.

Duration of test (contact time):

28 d

Initial conc.:

13 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral nutrient medium according to OECD 301B
- Test temperature: 23-24°C
- pH: Control: 7.5; functional control: 7.3; test substance: 7.4; toxicity control: 7.8
- pH adjusted: no


TEST SYSTEM
- Culturing apparatus: 5 L brown glass bottles filled with 3L test medium
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with CO2 free air
- Measuring equipment: Photometer, Dr. Lange CADAS 100
- Details of trap for CO2 and volatile organics if used: series of 3 gas wash bottles


SAMPLING
- Sampling frequency: day 1, 3, 6, 8, 10, 13, 16, 20, 23, 28, 29
- Sampling method: First wash bottle was removed at sampling date. CO2 was determined by titration subsequent to complete adsorption of the released CO2 in a basic solution (Backtitration of the residual Ba(OH)2 with 0,05 N HCI).


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

Reference substance:

acetic acid, sodium salt

Test performance:

The relation between IC and TC content of the test substance in the mineral medium was not determined at the beginning of the test, because the test substance was not fully soluble in the test medium.

Parameter:

% degradation (CO2 evolution)

Value:

19

Sampling time:

6 d

Parameter:

% degradation (CO2 evolution)

Value:

44

Sampling time:

13 d

Parameter:

% degradation (CO2 evolution)

Value:

54

Sampling time:

20 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

61

Sampling time:

28 d

Details on results:

In the control group a maximum of 28.1 mg CO2/L was formed after 28 days (quality criteria : < 40 mg C02/L). In case of the test substance the 10 %-pass level was passed after 4 days adaptation phase. In the 10-day window the test substance reached a mean degradation rate of 46 %. After 28 days a mean degradation rate of 61 % was reached.

Results with reference substance:

In the toxicity control the degradation came to 50 % after 13 days in a 10-day window and reached a maximum of 65 % after 28 days. The adaptation phase of the functional control changes after 2 days into the degradation phase (degradation > 10 %). The course of the degradation phase is very rapid and reaches a degradation rate of 63 % already on day 8. After 13 days the C02-production corresponds to a degradation rate of 72 %. The quality criteria degradation > 60 % after 14 days was fulfilled.

The test substance must be regarded to be not readily biodegradable in the 10-day window.

Table: CO₂-production and biodegradability for all determination points in the control, test substance samples and toxicity control samples.

Test day	Control mv	Test substance 13 mg/L			Test substance 13 mg/L			Toxicity control
	mg CO2	mg CO2		degr.	mg CO2		degr.	mg CO2		degr.
		gross	net	%	gross	net	%	gross	net	%
1 3 6 8 10 13 16 20 23 28 29 29	6.1 13.5 23.2 29.4 34.3 41.2 48.6 58.9 66.6 74.4 81.1 84.3	5.4 16.5 44.3 60.3 74.7 91.3 105.8 123.2 130.9 141.6 154.3 157.7	0 3.0 21.1 30.9 40.4 50.1 57.2 64.3 64.3 67.2 73.2 73.4	0 3 18 27 35 44 50 56 56 59 64 64	5.1 20.4 46.5 60.8 72.6 91.2 105.4 118.8 127.3 134.8 147.7 151.3	0 6.9 23.3 31.4 38.3 50.0 56.8 59.9 60.7 60.4 66.6 67.0	0 6 20 27 33 44 50 52 53 53 58 58	5.3 43.0 94.0 128.8 143.3 155.3 170.2 186.5 203.1 214.0 229.6 231.7	0 29.5 70.8 99.4 109.0 114.1 121.6 127.6 136.5 139.6 148.5 147.4	0 13 31 44 48 50 54 56 60 61 65 65

degr. = degradation

mv = mean value

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The ready biodegradability of the test substance in the Modified Sturm Test (OECD 301B) was assessed. The substance is not readily biodegradable but failing the 10d window.

Executive summary:

The ready biodegradability in the Modified Sturm Test was determined with a non-adapted activated sludge for the test substance over a period of 28 days. The study was made from January 30 to February 28, 1996 according to OECD Guideline 301 B. The test substance was tested in a concentration of 13 mg/L in duplicates, corresponding to a carbon content of 10.4 mgC/L. The biological degradation of the test substance was followed by titrimetric analyses of the quantity of CO2 which was produced by the respiration of bacteria. The degradation was finished on day 28; the last titration was made on day 29, after the soluble CO2 was turned out over a period of 24 h. The CO2 production was calculated as the percentage of total CO2 that the test substance could have theoretically produced based on carbon composition. Biodegradability is therefore expressed as a percentage ThCO2 (calculated by carbon content) and was calculated for each titration of CO2. In order to check the activity of the study system sodium acetate was used as positive control. It was degraded to 72 % after 13 days and therefore the quality criteria of "degradation > 60 % after 14 days” was fulfilled. In the toxicity control the degradation came to a rate of 50 % after 13 days and reached a maximum of 65 % after 28 days. The criteria of the guideline that the degradation in the toxicity control should be > 25 % after 14 days was fulfilled. The pass level of 10 % (start of the degradation phase) was reached by the test substance at the 4th day. In the 10-day window the test substance came to a mean degradation rate of 46 %. After 28 days a mean degradation rate of 61 % was reached. The test substance is not readily biodegradable because of failing the 10 d window. During the test no determination of nitrogen was assessed, which could possibly alter the result.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Chapter 13.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (CO2 evolution)

Value:

61

Sampling time:

28 d

Parameter:

% degradation (CO2 evolution)

Value:

54

Sampling time:

20 d

Parameter:

% degradation (CO2 evolution)

Value:

44

Sampling time:

13 d

Parameter:

% degradation (CO2 evolution)

Value:

19

Sampling time:

6 d

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Chapter 13.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

65

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

50

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

26

Sampling time:

7 d

Description of key information

No tests with the test item are available. The ready biodegradability of the first read across substance in the Modified Sturm Test (OECD 301B) was assessed. The substance is not readily biodegradable, failing the 10d window (reference 5.2.1 -1).

The ready biodegradability of the second read across substance in the respirometric method (OECD 301F) was assessed. The substance is not readily biodegradable, failing the 10d window (reference 5.2.1 -2).

It can be concluded that the test item is inherently biodegradable but failing the 10-day window.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater

Additional information

No tests with the test item are available. The two tests with read-across substances (details below) were used for the weight-of-evidence-approach.

The ready biodegradability in the Modified Sturm Test was determined with a non-adapted activated sludge for the first read across substance over a period of 28 days. The study was made from January 30 to February 28, 1996 according to OECD Guideline 301 B (Dr. U. Noack Loboratorium, 1996). The test substance was tested in a concentration of 13 mg/L in duplicates, corresponding to a carbon content of 10.4 mgC/L. The biological degradation of the test substance was followed by titrimetric analyses of the quantity of CO2 which was produced by the respiration of bacteria. The degradation was finished on day 28; the last titration was made on day 29, after the soluble CO2 was turned out over a period of 24 h. The CO2 production was calculated as the percentage of total CO2 that the test substance could have theoretically produced based on carbon composition. Biodegradability is therefore expressed as a percentage ThCO2 (calculated by carbon content) and was calculated for each titration of CO2. In order to check the activity of the study system sodium acetate was used as positive control. It was degraded to 72 % after 13 days and therefore the quality criteria of "degradation > 60 % after 14 days” was fulfilled. In the toxicity control the degradation came to a rate of 50 % after 13 days and reached a maximum of 65 % after 28 days. The criteria of the guideline that the degradation in the toxicity control should be > 25 % after 14 days was fulfilled. The pass level of 10 % (start of the degradation phase) was reached by the test substance at the 4th day. In the 10-day window the test substance came to a mean degradation rate of 46 %. After 28 days a mean degradation rate of 61 % was reached. The test substance is not readily biodegradable because of failing the 10 d window. During the test no determination of nitrogen was assessed, which could possibly alter the result.

 

The ready biodegradability of the second source substance in the respirometric method (OECD 301F) was assessed with a non-adapted activated sludge over a period of 28 days (Hoechst AG, 1994). The test substance was tested in a concentration of 127 mg/L in duplicates. The biological degradation of the test substance was followed by manometric determination of the oxygen consumption. In order to check the activity of the study system sodium benzoate was used as positive control. It was degraded to 83 % after 7 days and therefore the quality criteria of "degradation > 60 % after 14 days” was fulfilled. In the 10-day window the test substance came to a mean degradation rate of 50 %. After 28 days a mean degradation rate of 70 % was reached. The test substance is not readily biodegradable because of failing the 10 d window. During the test no determination of nitrogen was assessed, which could possibly alter the result.

 

Both read across studies show the same result, the substances are not readily biodegradable, failing the 10-day window. As the first source substance is a mixture of C16 and C18 carbon chains, no difference is expected to the biodegradation of the target substance. Therefore the target substance is expected to also be not readily biodegradable, failing the 10-day window.