N-ethylpropylamine

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:

key study

Study period:

10.2021 - 04.2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

TEST ITEM
- Name of test substance: N-ethylpropylamine
- Test substance No.: 05/0042-4
- Batch identification: B987 - 20210115
- CAS No.: 20193-20-8
- Contents: 87.4 +/- 0.3g/100g; water: 10.8g/100g
- Homogeneity: Homogeneous
- Physical state/Appearance: Liquid/colorless, clear

REFERENCE ITEM
- Name of reference substance: aniline
- Reference substance No.: 01/0298-26
- CAS No.: 62-53-3
- Purity: 99.99%
- Batch identification: STBH9290

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Inoculum: Activated sludge from a municipal sewage plant
- Origin: Wastewater sewage plant Lambsheim, Germany

Inoculum (activated sludge) was collected on 25th October 2021 from the aeration tank of the wastewater treatment plant of Lambsheim, Germany. A suitable aliquot of the suspension was sieved by a finely woven mesh with a mesh size of about 1 mm. Subsequently, this sludge suspension was aerated for about 2 days at 20 ± 2° C with carbon dioxide free air in order to reduce the inorganic carbon content in the blank controls. At the day of exposure, the aeration was stopped, the sludge suspension was washed for one time using drinking water and was allowed to settle. The supernatant was discarded, and the residue of the sludge suspension was filled up again with drinking water and the sludge of the suspension was adjusted to a final concentration 800 mg/L of dry weight. Aliquots of 0.5 mL from this suspension were added to the test vessels to obtain a sludge concentration of 4 mg/L dry substance in the test assays.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: For preparation of 20 L mineral medium 222 mL solution A, 22.2 mL solution B, 22.2 mL solution C and 22.2 mL solution D were added to 13.3 L deionized water and finally made up to 20 L.

- Solution A: KH2PO4 : 8.50 g; K2HPO4 : 21.75 g; Na2HPO4 × 2 H2O : 33.40 g; NH4Cl : 0.50 g (The compounds were dissolved with deionized water to 1000 mL; the pH value was
adjusted to 7.4.)
- Solution B: CaCl2 × 2 H2O : 36.40 g (The compound was dissolved with deionized water to 1000 mL)
- Solution C: MgSO4 × 7 H2O : 22.50 g (The compound was dissolved with deionized water to 1000 mL)
- Solution D: FeCl3 × 6 H2O : 0.25 g (The compound was dissolved with deionized water to 1000 mL)

- Test temperature: 20 +/- 2°C
- pH adjusted: yes, to 7.4
- Aeration of dilution water: no

TEST SYSTEM
- Culturing apparatus: 160 mL incubation bottle (fill volume: 100 mL)
- Number of culture flasks/concentration: 29 blank control assays, 31 test substance assays, 29 inhibition control assays, 17 reference substance assays, 5 assays for abiotic control, 20 blank controlo assays for DOC measurement, 20 test substance assays for DOC measurement

Test substance was added directly to the medium in the test substance assays, inhibition control assays as well as abiotic controls using a suitable micro syringe. All bottles were then sealed with butyl rubber septa and aluminum caps and shaken on an orbital shaker at a speed of about 150 rpm and incubated at a temperature of 20 +/- 2 °C. The Heaedspace-Design was chosen to prevent the evaporation of the test substance.

On each sampling days, three bottles of each test assay were sacrificed for TIC measurement except on the last day of exposure, where five bottles were sacrificed for the test substance assay. During sampling, one mL of 7 molar NaOH solution was injected with a syringe through the septum of each bottle. The bottles were shaken for about one hour afterwards. Carbon dioxide present in the headspace that was evolved during biological processes is dissolved in the alkaline solution during this process. Afterwards, the bottles were opened, and the total inorganic carbon (TIC) content trapped in the sodium hydroxide solution during the alkalization of the test assays was determined with a carbon analyzer. Single values of these test assays were used for mean value calculation of the biodegradation degree at Day 28 with a limit of confidence limit of 95%. The measured TIC-values were compared with the added amount of TOC and expressed as biodegradation degree and plotted as biodegradation curve. Additional assays such as BCDOC (blank control for DOC analysis) and TS-DOC (test substance assay for DOC analysis) were sampled in duplicates on the corresponding sampling days.

Reference substance:

aniline

Test performance:

Duration of the adaptation phase: approx.3 days;
Degree of biodegradation of the test substance at the end of the ten-days window, mean value: approx. 86% TIC/TOC;
Degree of biodegradation of the test substance at the end of exposure (mean value of five test assays, limit of confidence 95%): 100 +/- 1% TIC/TOC;
Degree of DOC elimination of the test substance at the end of exposure (mean value of two test assays +/- SD): 98 +/- 1%;
Degree of elimination of the test substance at physical chemical control at the end of exposure, mean value: <10% TIC/TOC;
Reference substance: aniline;
Degree of biodegradation of the reference substance after 14 days, mean value: 82% TIC/TOC;
Degree of biodegradation in the inhibition control after 14 days, mean value: 91% TIC/TOC;
Test temperature: 20 +/- 2 °C

Key result

Parameter:

% degradation (TOC removal)

Value:

100

Sampling time:

28 d

Parameter:

% degradation (DOC removal)

Value:

98

Sampling time:

28 d

Key result

Parameter:

% degradation (TOC removal)

Value:

86

Sampling time:

10 d

Remarks on result:

other: Degree of biodegradation at the end of the ten-day window

Details on results:

Validity criteria
- TIC-value in the blank control at the end of exposure (mean value): 0.9 mg/L; 
- Deviation of the degradation degree of the test substance at the end of exposure should be <20% between highest and lowest single value /five valid replicates): yes; 
- Degree of biodegradation of the reference substance should be >60% TIC/TOC after 14 days: yes; 
- Degree of biodegradation in the inhibition control should be >25% TIC/TOC after 28 days: yes; 
- TIC-value in the blank controls at the end of exposure should be <3 mg/L: yes; 
- Test temperature in the range of 20 +/- 2°C: yes

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance achieved a maximum degree of biodegradation 100 +/- 1% TIC/TOC (mean value of 5 replicates +/- SD) after an exposure period of 28 days.

The degree of biodegradation of the test substance at the end of the ten-day window was approx. 86% TIC/TOC (mean value).

DOC elimination was found to be 98 +/- 1% at the end of the exposure (mean +/- SD).

Executive summary:

To assess the biodegradability of N-ethylpropylamine, a test according to the OECD Guideline 310 was performed over a duration of 28 days. A Headspeace Test-Design was selected to prevent the evaporation of the test substance during the test duration.

N-ethylpropylamine achieved a maximum degree of biodegradation 100 +/- 1% TIC/TOC (mean value of 5 replicates +/- SD) after an exposure period of 28 days.
The degree of biodegradation of the N-ethylpropylamine at the end of the ten-day window was approx. 86% TIC/TOC (mean value).
Hence, the required pass level for ready biodegradability in accordance to the OECD Guideline 310 i.e., at least 60% of the theoretical maximum IC production must be attained within 10 days of the degradation exceeding 10% within the 28-day period of the test was accomplished.
N-ethylpropylamine can therefore be evaluated as readily biodegradable in this CO2 Test in sealed vessels (Headspace Test) based on the quantitative determination of the formed total inorganic carbon by comparison with the applied amount of total organic carbon (TOC). Evaluation was conducted in accordance with criteria of the OECD Test Guideline 310.
The mean value of degree of biodegradation was calculated by the single values of five test assays at the end of exposure with a limit of confidence of 95 %. DOC elimination was found to be 98 ±1% at the end of the exposure (mean +/- SD). Descriptive statistics (mean, standard deviation) were used where applicable.
The results in this study are consistent with all validity criteria and the test is valid according to the test guideline of this study. No deviations from the test guidelines or other incidents occurred during the course of the reported test, which may have influenced the results.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

experimental phase: 2005-04-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP-guideline study

Qualifier:

according to guideline

Guideline:

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

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 (e.g. location, sampling depth, contamination history, procedure): laboratory waste water treatment plant, fed with municipal sewage
- Pretreatment: The activated sludge was pre-aerated for about two days before the start of the test
- Initial cell/biomass concentration: 30 mg dry weight/L

Duration of test (contact time):

28 d

Initial conc.:

33 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: deionized water 1473 mL, mineral medium 19.5 mL, 7.5 mL inoculum (6 g dry weight /L)
- Test temperature: 22 ± 2 °C
- pH adjusted: no

SAMPLING
- Sampling frequency: daily measured
- Sampling method: measuring CO2 production

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: no
- Other: Inhibition control

Reference substance:

aniline

Parameter:

% degradation (CO2 evolution)

Value:

> 80 - < 90

Sampling time:

28 d

Parameter:

% degradation (CO2 evolution)

Value:

> 60 - < 70

Remarks on result:

other: at the end of the 10 day window

Details on results:

VALIDITY CRITERIA FULFILLED: YES
Deviation of the degradation degree of the test subst . in the plateau phase <20% : yes
Degradation degree of the reference substance >60% after 14 days : yes
Degradation degree in the inhibition control >25 % after 14 days : yes
DIC in the blank control by test begin at 20 mg/l TOC test concentration < 1 mg/l : yes
C02 production in the blank control <70 mg/l : yes

Results with reference substance:

Degradation degree 60 - 70% after 14 days

Table 1: Conductivity: measured values per day [mS/cm]; SCO2: summarized CO2 -production [mg/test vessel]

Day	BC1	BC2	RS	IH	TS1	TS2	RS SCO2	IH SCO2	TS1 SCO2	TS2 SCO2
0	51.7	51.3	51.9	52.9	53.2	52.6	-	-	-	-
1	51.5	51.1	51.6	52.7	53.1	52.5	3.4	2.6	1.9	1.9
2	51.3	50.8	51.2	52.5	52.8	52.2	4.1	1.9	1.9	1.9
3	50.9	50.4	50.3	51.6	52.0	51.8	7.9	5.7	4.9	1.9
4	50.6	50.0	47.5	46.4	49.9	50.3	27.0	43.0	18.6	11.0
5	50.2	49.5	45.1	41.6	48.1	48.3	41.4	75.7	28.5	22.4
6	49.9	49.2	43.9	39.8	46.7	46.5	48.3	87.1	36.9	33.8
7	49.6	48.8	43.7	38.5	45.2	44.8	47.5	94.7	46.0	44.5
8	49.2	48.4	42.1	37.5	44.0	43.4	56.6	99.3	52.1	52.1
9	48.9	48.1	41.5	36.7	42.9	42.3	58.9	103.1	58.2	58.2
10	48.6	47.8	41.1	35.9	42.0	41.4	59.7	106.9	62.7	62.7
11	48.3	47.5	40.6	35.1	41.2	40.6	61.2	110.7	66.5	66.5
12	48.0	47.2	40.0	34.3	40.4	39.8	63.5	114.5	70.3	70.3
13	47.7	46.9	39.4	33.6	39.8	39.2	65.8	117.5	72.6	72.6
14	47.4	46.6	38.8	32.9	39.1	38.7	68.1	120.6	75.7	74.2
15	47.2	46.4	38.6	32.3	38.7	38.2	68.1	123.6	77.2	76.4
16	46.9	46.1	38.3	31.5	38.1	37.7	68.1	127.4	79.5	78.0
17	46.8	45.9	38.1	30.9	37.8	37.4	68.1	130.5	80.2	78.7
18	46.7	45.8	37.9	30.2	37.4	37.0	68.8	135.0	82.5	81.0
19	46.6	45.7	37.7	29.5	37.1	36.7	69.6	139.6	84.0	82.5
20	46.5	45.6	37.6	28.9	36.8	36.4	69.6	143.4	85.6	84.0
21	46.4	45.4	37.3	28.5	36.5	34.1	71.1	145.7	87.1	85.6
22	46.3	45.3	36.9	28.1	36.3	35.9	73.4	148.0	87.8	86.3
23	46.1	45.2	36.6	27.6	36.0	35.6	74.2	150.2	88.6	87.1
24	46.1	45.1	36.5	27.3	35.8	35.4	74.9	152.5	90.1	88.6
25	46.0	45.0	36.2	26.9	35.6	35.2	76.4	154.8	90.9	89.4
26	45.8	44.9	36.0	26.5	35.4	35.0	76.4	156.3	90.9	89.4
27	45.7	44.8	35.8	26.1	35.2	34.8	77.2	158.6	91.7	90.1
28	45.6	44.6	35.5	25.8	35.0	34.7	79.5	162.4	91.7	89.4
29	45.2	44.1	34.9	25.0	34.6	34.3

Remark: The measured values of day 29 are influenced by C02 stripping and therefore added to the values of 28. Correlation for calculation from the conductivity change to the produced C02 amount in the test vessels: y = 7,6097x+2,6191

Table 2: Degradation degree [%] (CO2/ThCO2)

Test duration [days]	RS	IH	TS1	TS2	TS mv
0	0	0	0	0	0
1	3	1	2	2	2
2	4	1	2	2	2
3	7	3	4	2	3
4	25	20	17	10	14
5	38	34	26	20	23
6	44	40	33	31	32
7	43	43	42	40	41
8	52	45	47	47	47
9	54	47	53	53	53
10	54	49	57	57	57
11	56	50	60	60	60
12	58	52	64	64	64
13	60	54	66	66	66
14	62	55	68	67	68
15	62	56	70	69	70
16	62	58	72	71	72
17	62	59	73	71	72
18	63	62	75	73	74
19	64	64	76	75	76
20	64	65	77	76	77
21	65	66	79	78	79
22	67	67	79	78	79
23	68	68	80	79	80
24	68	69	81	80	81
25	70	71	82	81	82
26	70	71	82	81	82
27	70	72	83	82	83
28	73	74	83	81	82

(ThCO2 [mg/test vessel]: RS = 109.6; IH = 219.5; TS1 = 110.6; TS2 = 110.4)

Table 3: DOC eliminiation

	BC 1	BC 2	BC mv	RS	IH	TS 1	TS 2	TS mv
DOC at begin of exposure [mg/L]	0.8	0.7	0.8	18.9	34.8	19.6	18.6
	0.7	0.8		19.1	36.3	19.6	19.0
DOC at end of exposure [mg/L]	1.3	1.5	1.4	3.4	3.8	1.4	1.4
	1.3	1.4		3.4	4.0	1.5	1.4
DOC elimination [%]				89	93	99	100	100

Table 4: pH values

	BC 1	BC 2	RS	IH	TS 1	TS 2
pH-value at pre-incubation before and after correction	7.8	7.8	7.8	7.8	7.8	7.8
	7.4	7.4	7.4	7.4	7.4	7.4
pH-value at end of exposure	7.2	7.2	7.5	7.2	7.2	7.2

Legend:

BC = blank control       RS = reference substance        IH = inhibition control   TS = test substance    mv = mean value 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Executive summary:

N-ethylpropylamine (CAS 20193 -20 -8) is readily biodegradable according to the OECD criteria.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
OASIS Catalogic v5.14.1.5

2. MODEL (incl. version number)
CATALOGIC 301C v11.16

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See section 'Test Material'.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF.

5. APPLICABILITY DOMAIN
See attached QPRF.

6. ADEQUACY OF THE RESULT
- The model is scientifically valid (see attached QMRF).
- The model estimates the biodegradability of a substance Screening information on the ready biodegradability is required for substances manufactured or imported in quantities of 1 t/y or more. Depending on the results, further information may be required for substances manufactured or imported in quantities of 100 t/y or more (simulation testing on ultimate degradation in surface water/soil/sediment). Column 2 of REACH Annex VII provides exemptions for conducting the study. It does not need to be conducted if the substance is inorganic. According to column 2 of REACH Annex IX, testing is not required if the substance is highly insoluble in water, or the substance is readily biodegradable.
- See attached QPRF for reliability assessment.

Principles of method if other than guideline:

Estimation of ready biodegradation in water using CATALOGIC v5.14.1.5 BOD 28 days MITI (OECD 301C) v11.16

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: model calculation

Duration of test (contact time):

28 d

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

-Concomitant predictions:

Ready degradable

Primary Half Life = 9.49 days

Ultimate Half Life = 16.16 days

- Predicted value (model result): O2 -consumption (BOD) = 0.70 ± 0.0479

Interpretation of results:

readily biodegradable

Remarks:

according to OECD criteria

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
OASIS Catalogic v5.14.1.5

2. MODEL (incl. version number)
CATALOGIC Kinetic 301F v14.17

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See section 'Test Material'.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF.

5. APPLICABILITY DOMAIN
See attached QPRF.

6. ADEQUACY OF THE RESULT
- The model is scientifically valid (see attached QMRF).
- The model estimates the biodegradability of a substance Screening information on the ready biodegradability is required for substances manufactured or imported in quantities of 1 t/y or more. Depending on the results, further information may be required for substances manufactured or imported in quantities of 100 t/y or more (simulation testing on ultimate degradation in surface water/soil/sediment). Column 2 of REACH Annex VII provides exemptions for conducting the study. It does not need to be conducted if the substance is inorganic. According to column 2 of REACH Annex IX, testing is not required if the substance is highly insoluble in water, or the substance is readily biodegradable.
- See attached QPRF for reliability assessment.

Principles of method if other than guideline:

Estimation of ready biodegradation in water using CATALOGIC v5.14.1.5, CATALOGIC Kinetic 301F v14.17:
The Endpoint is Biological Oxygen Demand (BOD) according to OECD 301F. BOD is the oxygen used by aerobic microorganisms to mineralize the test substance after a given time (28 days), corrected for oxygen uptake by the blank inoculum control after the same time, and related to the theoretical oxygen demand needed for full mineralization of the substance.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Model calculation

Duration of test (contact time):

28 d

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

28 d

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

- Concomitant predictions :

Ready degradable

Primary Half Life = 1.26 days

Ultimate Half Life = 10.90 days

Start day of Calc. 10 days window => 3

BOD calculated at 10 days window = 0.5830

Classification of Calc. 10 days window = not ready

- Predicted value (model result): BOD (28 days) = 0.83 ± 0.0541

 

Interpretation of results:

readily biodegradable, but failing 10-day window

Remarks:

according to OECD criteria

Description of key information

The substance is readily biodegradable (according to OECD criteria).

According to a study conducted in compliance with the OECD Test Guideline 310, N-ethylpropylamine was determined to be readily biodegradable according to OECD criteria. 
N-ethylpropylamine achieved a maximum degree of biodegradation 100 +/- 1% TIC/TOC (mean value of 5 replicates +/- SD) after an exposure period of 28 days. The degree of biodegradation of the N-ethylpropylamine at the end of the ten-day window was approx. 86% TIC/TOC (mean value).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

In addition to the above mentioned key study (BASF AG 2022), a supporting study was conducted according to OECD guideline 301 B considering the ready biodegradability of the test substance available (BASF AG 2005). In this test the test substance was readily biodegradable.

Furthermore, two calculations were conducted to further assess the biodegradation potential of n-ethylpropylamine. The substance was within the applicability domain of both models:

- OASIS Catalogic v5.14.1.5, CATALOGIC 301C v11.16: Ready degradable, 70% degradation in 28 days (BASF SE, 2020)

- OASIS Catalogic v5.14.1.5, CATALOGIC Kinetic 301F v14.17: Ready degradable but failing the 10 -d window, 83% degradation in 28 days (BASF SE, 2020)

 

Under consideration of the key study (BASF AG 2022) and all available supporting information, it can be concluded, that n-ethylpropylamine is readily biodegradable (according to OECD criteria).