Hexylamine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

other: as mentined below

Principles of method if other than guideline:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Hexylamine by bacteria as a test inoculum. Two tests were carried out for studying the biodegradation of test substance Hexylamine. They are standard tests and low conc. tests.

GLP compliance:

not specified

Oxygen conditions:

anaerobic

Inoculum or test system:

other: bacteria

Details on inoculum:

- Method of cultivation: The seeding bacteria had been cultured in a continuous anaerobic bioreactor at 37 + 1°C. Synthetic sewage, composed of glucose, peptone and corn steap liquor (carbon ratio = 1:1:2), is supplied into the reactor (3.0 g-C/l, 8.0 g-CS./.d). In this culture, > 95% acidic decomposition and > 90% methanogenic decomposition are achieved.

- Concentration of sludge: 100 mg/l (For both standard and low conc. tests)

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

other: test mat. (Test 1 - standard conc. test)

Initial conc.:

3 mg/L

Based on:

other: test mat. (Test 2 - low conc. test)

Parameter followed for biodegradation estimation:

DOC removal

Remarks:

(Test 1 - standard conc. test)

Parameter followed for biodegradation estimation:

other: Chromatography (Test 2 - low conc. test)

Details on study design:

TEST CONDITIONS
- Composition of medium: Organic medium was used for the study. Composition of the medium contains Glucose and glutamic acid which was added at 15 mg-C/l each test vessels.

- Additional substrate: JIS BOD5 inorganic mediums are used. NaNH4HPO4, is added for nitrogen source

- Test temperature: 37 + 0.5”C

- pH: 7.0

- pH adjusted: Yes, pH is adjusted to 7. NaHCO3 is added for the buffer effect.

TEST SYSTEM
- Culturing apparatus: Test vials are used for the study.

- Number of culture flasks/concentration: 50 ml vials (total capacity is 68 m) are employed. Ten vials are prepared for test compound.

- Method used to create anaerobic conditions: Test procedures are carried out in a glove box with N, atmosphere. The oxygen-free water is used.

- Other: Sodium sulfide was added for reductive condition at a conc. of 50 mg-S/l.

SAMPLING
- Sampling frequency: Test period is 4 weeks. At the beginning (t = 0 day) and after every week (t = 7,14,21,28 d), two vials are opened simultaneously and analyzed.

Parameter:

% degradation (DOC removal)

Value:

< 30

Sampling time:

28 d

Remarks on result:

other: Test 1 (in Standard test % degradation was determined after 28 days).

Parameter:

other: chromatography

Value:

100

Sampling time:

21 d

Remarks on result:

other: Test 2 (in low conc. test).

Validity criteria fulfilled:

not specified

Interpretation of results:

other: Test chemical was determined to be non-biodegradable in standard test and readily biodegradable in low conc. test.

Conclusions:

The percentage degradation of the test compound was determined to be less than 30% in > 28 days in standard test and 100% degradation in 21 days in low conc. test, respectively. Thus, based on the percentage degradation, the test chemical was considered to be non-biodegradable in standard test and readily biodegradable in low conc. test.

Executive summary:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substanceHexylamine by bacteriaas a test inoculum. Two tests were carried out for studying the biodegradation of test substanceHexylamine. They are standard tests and low conc. tests.Seeding bacteria was used as a test inoculum.The seeding bacteria had been cultured in a continuous anaerobic bioreactor at 37 + 1°C.Synthetic sewage, composed of glucose, peptone and corn steap liquor (carbon ratio = 1:1:2), is supplied into the reactor (3.0 g-C/l, 8.0 g-CS./.d). In this culture, > 95% acidic decomposition and > 90% methanogenic decomposition are achieved.

A standard test and low conc. tests using 50 ml vials (total capacity: 68 ml) was employed. Ten test vials were prepared under the same conditions, and they were set in a water bath at 37°C ± 0.5”C. The original solution was added to the test inoculum and organic medium in oxygen-free water. At the starting time and after every week, two vials were opened simultaneously, and the concentration of organic compound was analyzed. The concentration of organic compound was determined by dissolved organic carbon (DOC) in the standard test and by chromatography in low conc. test.Biodegradation ratio is determined by analysing the decrease of DOC in the standard test.Reproducibility is confirmed by the biodegradation ratio of benzoic acid being > 78% after 14 days.

The percentage degradation of the test compound was determined to be less than 30% in > 28 days in standard test and 100% degradation in 21 days in low conc. test, respectively. Thus, based on the percentage degradation, the test chemical was considered to be non-biodegradable in standard test and readily biodegradable in low conc. test.

Description of key information

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Hexylamine by bacteria as a test inoculum (Takashi Kameya et. al; 1995). Two tests were carried out for studying the biodegradation of test substance Hexylamine. They are standard tests and low conc. tests. Seeding bacteria was used as a test inoculum. The seeding bacteria had been cultured in a continuous anaerobic bioreactor at 37 + 1°C.Synthetic sewage, composed of glucose, peptone and corn steap liquor (carbon ratio = 1:1:2), is supplied into the reactor (3.0 g-C/l, 8.0 g-CS./.d). In this culture, > 95% acidic decomposition and > 90% methanogenic decomposition are achieved.

A standard test and low conc. tests using 50 ml vials (total capacity: 68 ml) was employed. Ten test vials were prepared under the same conditions, and they were set in a water bath at 37°C ± 0.5”C. The original solution was added to the test inoculum and organic medium in oxygen-free water. At the starting time and after every week, two vials were opened simultaneously, and the concentration of organic compound was analyzed. The concentration of organic compound was determined by dissolved organic carbon (DOC) in the standard test and by chromatography in low conc. test. Biodegradation ratio is determined by analysing the decrease of DOC in the standard test. Reproducibility is confirmed by the biodegradation ratio of benzoic acid being > 78% after 14 days.

The percentage degradation of the test compound was determined to be less than 30% in > 28 days in standard test and 100% degradation in 21 days in low conc. test, respectively. Thus, based on the percentage degradation, the test chemical was considered to be non-biodegradable in standard test and readily biodegradable in low conc. test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various study for the test compound Hexylamine(CAS No. 111-26-2) and for its read across substance were reviewed for the biodegradation end point which are summarized as below:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance Hexylamine by bacteria as a test inoculum (Takashi Kameya et. al; 1995). Two tests were carried out for studying the biodegradation of test substance Hexylamine. They are standard tests and low conc. tests. Seeding bacteria was used as a test inoculum. The seeding bacteria had been cultured in a continuous anaerobic bioreactor at 37 + 1°C.Synthetic sewage, composed of glucose, peptone and corn steap liquor (carbon ratio = 1:1:2), is supplied into the reactor (3.0 g-C/l, 8.0 g-CS./.d). In this culture, > 95% acidic decomposition and > 90% methanogenic decomposition are achieved.

A standard test and low conc. tests using 50 ml vials (total capacity: 68 ml) was employed. Ten test vials were prepared under the same conditions, and they were set in a water bath at 37°C ± 0.5”C. The original solution was added to the test inoculum and organic medium in oxygen-free water. At the starting time and after every week, two vials were opened simultaneously, and the concentration of organic compound was analyzed. The concentration of organic compound was determined by dissolved organic carbon (DOC) in the standard test and by chromatography in low conc. test. Biodegradation ratio is determined by analysing the decrease of DOC in the standard test. Reproducibility is confirmed by the biodegradation ratio of benzoic acid being > 78% after 14 days.

The percentage degradation of the test compound was determined to be less than 30% in > 28 days in standard test and 100% degradation in 21 days in low conc. test, respectively. Thus, based on the percentage degradation, the test chemical was considered to be non-biodegradable in standard test and readily biodegradable in low conc. test.

Estimation Programs Interface Suite (EPI suite, 2016) was run to predict the biodegradation potential of the test compound Hexylamine (CAS no. 111- 26 -2) in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that Hexylamine is expected to be readily biodegradable.

28-days Manometric respirometry test following the OECD guideline 301Fto determine the ready biodegradability of the test item n-hexylamine (CAS No. 111-26-2) (UERL study report, Sustainability Support Services (Europe) AB, Report no. 111-26-2/01/2015/RBD, 2015). % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD₂₈value of n-hexylamine (CAS No. 111-26-2) was observed to be 1.447mgO₂/mg. ThOD was calculated as 2.846 mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was found to be 50.84%.Based on the results, the test item, under the test conditions, was found to be inherently biodegradable at 20 ± 1°C over a period of 28 days.

Biodegradation study was conducted for > 28 days for evaluating the percentage biodegradability of test substance Hexylamine by anaerobic bacteria (Takashi Kameya et. al; 1995). Two test were carried out by using different conc. of test chemical and inoculum. Anaerobic bacteria was used as a test inoculum. The cultivated bacteria was prepared for seeding as follows. The bacteria suspension was drowned, homogenized, and separated with a centrifuge at 3000 rev./min for 10 min. The deposit was washed by the basal medium solution and separated again with a centrifuge. The deposit was dissolved again in the basal medium solution and its concentration was determined. This original suspension of bacteria was seeded in the test vials and its concentration was reconfirmed. The seeding bacteria had been cultured by a synthetic sewage in a continuous bioreactor at 37 + 1°C. 100 and 30 mg/l conc. was used for both inoculum and test substance conc., respectively.

The test involve the use of 50 ml vials (total capacity: 68 ml). Ten test vials were prepared under the same conditions, and they were set in a water bath at 37°C ± 0.5”C. The original solution was added to the test inoculum and basal medium solution, which was prepared by organic medium and/or inorganic medium in oxygen-free water. At the starting time and after every week, two vials were opened simultaneously, and the concentration of organic compound was analyzed. The concentration of organic compound was determined by dissolved organic carbon (DOC) or chromatography. Biodegradation ratio is determined by analyzing the decrease of DOC. The percentage degradation of the test compound was determined to be 50% in test 1 and 47% in > 28 days test 2, respectively. Thus, based on the percentage degradation, the test chemical was considered to be undergoe slow biodegradation under the given test conditions.

 

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test substance n-butylamine (J-CHECK, 2016). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 66% by BOD(NO2), 85% by BOD(NH3), 98% by TOC removal and 100% by HPLC in 14 days. Thus, the substance n-butylamine is considered to be readily biodegradable in water.

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance 1-Aminopropane (J-CHECK, 2016). Concentration of inoculum i.e, sludge used was 100 mg/l and initial test substance conc. used in the study was 30 mg/l. The percentage degradation of test substance was determined to be 49 and 85% by O2 consumption, BOD(NO2), 67 and 117% by O2 consumption , BOD(NH3), 88 and 100% by TOC removal and 100% by Test. mat. analysis, HPLC in 14 days. Thus, the substance 1-Aminopropane is considered to be readily biodegradable in water.

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test substance Hexamethylene diamine (J-CHECK, 2016). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 55.5% by BOD, 96.9% by TOC removal and 100% by GC in 14 days. Thus, the substance Hexamethylene diamine is considered to be readily biodegradable in water.

Biodegradation study was conducted for 21 days for evaluating the percentage biodegradability of test substance n-Amylamine (J-CHECK, 2016). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 75% by BOD(NO2), 93% by BOD(NH3), 97% by TOC removal and 100% by HPLC in 21 days. Thus, the substance n-Amylamine is considered to be readily biodegradable in water.

The objectives of the test were to isolate a bacterial strain capable of degrading pentylamine and aniline and to define the optimal pentylamine and aniline degradation conditions for this bacterial strain. The bacterial strain was isolated from activated sludge obtained from a North eastern China treatment facility for petrochemical wastewater rich in pentylamine and aniline. Once the strain was isolated, five triplicate (5) batch tests were used to establish the conditions for maximum pentylamine degradation, by varying one at a time the following five factors: temperature, pH, reaction time, pollutant concentrations and aeration rate. In a final test, oil refinery sludge was inoculated with the strain and tested for the degradation of pentylamine under optimal conditions, while observing the degradation pathway of pentylamine. The isolated strain, PN1001, is a member of the Pseudomonas species and it was capable of degrading pentylamine. The optimal reactor conditions for the degradation of a mixture of pentylamine, at a concentration ranging between 150 and 200 mg/L, were found to be 30°C at a pH of 7.0, under a reaction time of 24 h and a maximum solution dissolved oxygen level of 6 mgO₂/L. Under such conditions, the strain PN1001 degraded 93% of the pentylamine. Once inoculated with the strain, oil refinery sludge degraded 93% of the pentylamine, compared to the strain alone which degraded 72% likely because of the sludge’s buffering effect against the toxic environment.

Although 1 supporting data i.e, experimental study of the target substance Hexylamine, indicates that the test chemical is inherently biodegradable in nature, but the key study which is from a k2 level publication and other supporting data for target and read across substance indicate that the substance Hexylamine is readily biodegradable in nature. Thus, based on the overall results for target and read across substance, it can be concluded that the test substance, Hexylamine can be expected to be readily biodegradable in nature.