7-(4-ethyl-1-methyloctyl)quinolin-8-ol

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2019

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

7-(4-ethyl-1-methyloctyl)quinolin-8-ol

EC Number:

277-531-1

EC Name:

7-(4-ethyl-1-methyloctyl)quinolin-8-ol

Cas Number:

73545-11-6

Molecular formula:

C20H29NO

IUPAC Name:

7-(5-ethylnonan-2-yl)quinolin-8-ol

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Sponsor / 1702-18-01/O
- Expiration date of the lot/batch: 25. Mar. 2021
- Purity test date: 26. Mar. 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
Stored in a tightly closed vessel at room temperature under dry conditions in the dark
- Solubility and stability of the test substance in the solvent/vehicle:
Stability unknown. Water solubility <0.1g/L; Acetione >1 g/L; ethanol, Ch3CN & DMSO, unknown

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
The carbon content of 80.22% was calculated by molecular formula given by the sponsor. The test item was weighed directly, the amounts were calculated from the crbon contnent of the test item

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf. Date of collection: 28 September 2018, Batch number: 20180928

- Pretreatment: The sludge was filtrated, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 4940 mg of suspended solids/L.

- Concentration of inoculum: 25.0 mg/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

other: organic carbon

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: 1 litre mineral medium contains; 10mL Solution (A), 1mL Solution (B), 1 mL Solution (C), 1 mL Solution (D)
A) 8.5g KH2PO4
21.75g K2HPO4
33.4g Na2HPO4*2H2O
0.5g NH4Cl
ad 1000mL H2O demin.
pH 7.4

B) 27.5g CaCl2
ad 1000 mL H2O demin.
C) 22.5g MgSO4*7H2O
ad 1000mL H2O demin.
D) 0.25g FeCl3*6H2O
0.4g Na2EDTA*2H2O
ad 1000mL H2O demin.

- Additional substrate: n/a
- Solubilising agent (type and concentration if used): not used
- Test temperature: 20.1 - 22.8 ºC witjut direct light
- pH:
- pH adjusted: no
- Aeration of dilution water: no
- Suspended solids concentration:
- Continuous darkness: yes/no
- Other:

TEST SYSTEM
- Culturing apparatus: 1500mL flasks
- Number of culture flasks/concentration: 2 replicates
- Method used to create aerobic conditions: Test vessels were aerated with purified (by active charcole), CO2-scrubbeed, moistened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5M NaOH. To contrl the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 befre reaching the test vessels.
- Method used to create anaerobic conditions:
- Measuring equipment: TOC multi N/C 2100S, Analytik Jena
- Test performed in closed vessels due to significant volatility of test substance:
- Test performed in open system:
- Details of trap for CO2 and volatile organics if used: Scrubber containing 0.25M NaOH
- Other:

SAMPLING
- Sampling frequency: Day 0, 3, 7, 9, 11, 14, 17, 23 & 29
- Sampling method: From each front scrubber flask, samples were taken i order to determine the emitted Co2. The sample volume was 1mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2. On day 28, 5mL HCl 2M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.
- Sterility check if applicable:
- Sample storage before analysis:
- Other:

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: Yes
- Toxicity control: Yes

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Details on results:

All validity criteria were met.
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation reached 2.4 %. Both replicates of the test item showed good correspondence.
If degradation in the toxicity flask is below 25 % after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 35.8 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 24.9 mg/L”.
For pure substances ready biodegradability is defined in the guidelines as degradation surpassing 60 % within 10 days after reaching a level of 10 %.
Because the test item is a mixture, the 10-day window has not to be taken into account. For the test item 7-(4-ethyl-1-methyloctyl)quinolin-8-ol no biodegradation was observed after 28 days. The 10-day-window could not be determined. The criterion of reaching 60% of degradation after 28 days is not met. 7-(4-ethyl-1-methyloctyl)quinolin-8-ol is therefore considered as “not readily biodegradable”.
No observations were made which might cause doubts concerning the validity of the study outcome.
The result of the test can be considered valid.

Any other information on results incl. tables

Validity

Parameter	Criterion	Found	Assessment
IC content of test item solution in medium	< 5% of TC	0%	Valid
CO2emitted by the controls	< 70 mg/L	11.4 mg/L	Valid
Difference within replicates	< 20%	5.9%	Valid
Degradation of positive control >60%	<= 14 days	10 days	Valid
Degradation in the toxicity flask on day 14	> 25%	35.8%	Non-toxic

Tables

In the following tables, the IC values (given in mg/L) which were measured in the samples of the scrubber flasks are stated.

Table8.1 -a       IC values in mg/L of apparatus blanks, blank controls, front scrubber

Day	Apparatus blank 1	Apparatus blank 2	Blank control 1	Blank control 2
0	3.08	3.42	3.82	3.30
3	5.83	7.47	10.23	27.11
7	9.08	11.06	17.18	37.5
9	12.10	13.31	20.64	54.43
11	12.90	15.05	24.55	62.56
14	14.27	16.80	28.49	67.74
17	16.05	18.07	30.08	70.79
23	21.68	22.44	33.55	90.80
29	28.82	30.34	41.86	119.10

Table 8.1 -b       IC values in mg/L of positive control, test flasks, front scrubber

Day	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	3.00	3.81	3.80	5.57	9.56	3.45
3	19.96	14.32	12.77	17.08	14.46	24.71
7	133.48	155.99	25.07	26.85	19.10	109.75
9	196.35	222.97	32.84	37.08	21.39	228.34
11	262.22	263.31	37.25	43.59	23.13	243.27
14	305.66	302.25	40.90	53.93	27.17	273.66
17	325.59	313.56	62.78	58.78	32.03	280.48
23	357.17	335.87	54.02	66.32	34.28	313.73
29	389.43	352.28	67.62	88.94	43.90	320.24

In the following tables, the IC values which were measured in the samples of the back scrubber flasks are stated.

Table 8.1 -c       IC values in mg/L of blank controls, apparatus blanks, back scrubber

Day	Apparatus blank 1	Apparatus blank 2	Blank control 1	Blank control 2
0	4.06	4.01	3.48	3.90
29	3.77	3.82	4.36	6.07

Table 8.1 -d       IC values in mg/L of positive control, test flasks, back srubber

Day	Positive Control 1	Positive COntrol 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	3.79	4.69	3.62	9.50	7.91	5.48
29	4.47	4.09	4.53	5.98	8.4	13.10

Net IC

For each flask, the net IC was calculated by subtracting the mean IC value of the apparatus blanks of the corresponding sampling date from the remaining IC values. Exception: Values of day 0 do not need to be corrected.

The value of day 0 of the apparatus blank was subtracted from the apparatus blanks of the corresponding sampling dates in advance.

The net IC values are presented in the following table.

Table 8.1 -e       Net IC-values in mg/L of front scrubber flasks

Day	Blank Cntrol 1	Blank Control 2	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	3.8	3.3	3.0	3.8	3.8	5.6	9.6	3.5
3	6.8	23.7	16.6	10.9	9.4	13.7	11.1	21.3
7	10.4	30.7	126.7	149.2	18.2	20.0	12.3	102.9
9	11.2	45.0	186.9	213.5	23.4	27.6	11.9	218.9
11	13.8	51.8	251.5	252.6	26.5	32.9	12.4	232.6
14	16.2	55.5	293.4	290.0	28.6	41.6	14.9	261.4
17	16.3	57.0	311.8	299.8	49.0	45.0	18.2	266.7
23	14.7	72.0	338.4	317.1	35.2	47.5	15.5	294.9
29	15.5	92.8	363.1	325.9	41.3	62.6	17.6	293.9

Table 8.1 -f       Net IC-values in mg/L of back scrubber flasks

Day	Blank Control 1	Blank Control 2	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	3.5	3.9	3.8	4.7	3.6	9.5	7.9	5.5
29	4.6	6.3	4.7	4.3	4.8	6.2	8.6	13.3

In the followingtable, the pH at the end of the test (before addition of HCl) is given:

Table 8.1 -g       pH in test flasks on day 28

Day	Blank control 1	Blank control 2	Positive control 1	Positive control 2	Test 1	Test 2	Abiotic control	Toxicity control
28	7.6	7.6	7.4	7.4	7.5	7.5	6.9	7.4

Equations

Emitted carbon in mg/L

Emitted carbon in mg/L test solution in the respective vessel at time t was calculated using the following equation:

emittC= ((IC(t)-IC(0))*VolNaOH(t)) / Vol_Testvessel

with

emittC       emitted carbon in mg/L test solution

IC(t)        net inorganic carbon in mg/L NaOH in the respective vessel at time t

IC(0)         net inorganic carbon in mg/L NaOH in the respective vessel at the start of the test

VolNaOH (t)       remaining volume NaOH in L in the scrubber at time t (Volume at t=0 (here: 0.1L) -∑(all sample volumes up to time t))

Vol_Testvessel       test vessel volume in L (here: 1.5)

For day 29, the IC content of both scrubber flasks was taken into account.

Calculation of emitted carbon is necessary for the assessment of validity. The value obtained with the equation is multiplied with 3.667 (44/12) in order to obtain emitted CO₂.

Degradation in %

The percentage biodegradation in the test flasks was calculated from:

% degradation = ((emittedC(Test) in mg/L - Mean emittedC(Controls)in mg/L) / addedC in mg/L)*100%

Degradation in positive control and toxicty flasks was calculated analogously.

Abiotic degradation was calculated from:

% degradation = (emittedC(abiotic)in mg/L) / (addedC in mg/L) * 100%

Calculation Results

Emitted Carbon in mg/L

In the following table, the calculated emitted carbon (from net IC given earlier and equation stated above) is presented.

Table 8.3 -a       Emitted carbon in mg/L

Day	Blank Control 1	Blank Control 2	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
3	0.20	1.35	0.90	0.47	0.37	0.54	0.10	1.18
7	0.43	1.79	8.08	9.50	0.94	0.94	0.18	6.50
9	0.48	2.69	11.89	13.56	1.27	1.43	0.15	13.93
11	0.64	3.11	15.90	15.92	1.45	1.75	0.18	14.66
14	0.78	3.30	18.39	18.12	1.57	2.29	0.34	16.34
17	0.78	3.36	19.35	18.55	2.83	2.47	0.54	16.50
23	0.68	4.26	20.79	19.42	1.95	2.60	0.37	18.07
29	0.72	5.49	22.09	19.76	2.30	3.50	0.49	17.81

Degradation Values

In the following table, the percentage biodegradation is presented:

Table 8.3 -b       Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Toxicity Control
3	0.6	-1.5	-0.5	-2.0	-1.2	-1.6	0.5	1.0
7	34.9	42.0	38.5	-0.8	-0.8	-0.8	0.9	13.5
9	51.6	60.0	55.8	-1.6	-0.8	-1.2	0.7	30.9
11	70.3	70.3	70.3	-2.1	-0.6	-1.3	0.9	32.0
14	81.9	80.5	81.2	-2.3	1.2	-0.6	1.6	35.8
17	86.5	82.5	84.5	3.7	2.0	2.9	2.6	36.1
23	91.8	84.9	88.3	-2.6	0.7	-0.9	1.8	39.0
29	95.1	83.4	89.2	-3.9	2.0	-1.0	2.4	36.8

Because the values of day 29 are the sum of the IC vlues in both scrubber flasks, an increase (IC values in flasks B of the test higher than in those of the control) or a decrease (IC values in flasks B of the test lower than in those of the control) of degradation can be observed.

As the measured IC values in the test flasks are very low, measurement uncertainties lead to negative degradation values while in fact no degradation has taken place.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

All validity criteria were met.
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation reached 2.4 %. Both replicates of the test item showed good correspondence.
If degradation in the toxicity flask is below 25 % after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 35.8 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 24.9 mg/L”.
For pure substances ready biodegradability is defined in the guidelines as degradation surpassing 60 % within 10 days after reaching a level of 10 %.
For the test item 7-(4-ethyl-1-methyloctyl)quinolin-8-ol no biodegradation was observed after 28 days. The 10-day-window could not be determined. The criterion of reaching 60% of degradation after 28 days is not met. 7-(4-ethyl-1-methyloctyl)quinolin-8-ol is therefore considered as “not readily biodegradable”.
No observations were made which might cause doubts concerning the validity of the study outcome.
The result of the test can be considered valid.

Executive summary:

The test item 7-(4-ethyl-1-methyloctyl)quinolin-8-ol was tested using a concentration of nominally 20 mg organic carbon/L7-(4-ethyl-1-methyloctyl)quinolin-8-ol in test medium following OECD 301B and EU-Method C.4-C.

 

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control surpassed the pass level of 60 % after 10 days.

 

The following data were determined for the test item7-(4-ethyl-1-methyloctyl)quinolin-8-ol:

10-day-window:                                           not detected
degradation at the end of the test                   0 %
pass level following guideline:                       60 % at the end of 10-day-window fo pure substances

respective 60 % at the end of the test for mixtures

For the test item7-(4-ethyl-1-methyloctyl)quinolin-8-ol no biodegradation was observed after 28 days. The 10-day-window could not be determined. The criterion of reaching 60% of degradation after 28 days is not met.7-(4-ethyl-1-methyloctyl)quinolin-8-ol is therefore considered as “not readily biodegradable”.