Petroleum resins

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

Study period:

04. Apr. 2018 to 08. May 2018

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)

Version / remarks:

OECD Guidelines for the Testing of Chemicals, Part 301 B, adopted 17. Jul. 1992 “CO2-Evolution-Test (Modified STURM Test)“

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Commission Regulation (EC) No. 440/2008, Method C.4-C, adopted 30. May 2008 “CO2-Evolution-Test”

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

No further details specified in the study report.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Specification
Activated sludge from a biologic sewage treatment plant was used as inoculum. The chosen plant treats mostly domestic sewage.

Source and Pre-Treatment of inoculum
Source
The sludge was taken from the activation basin of sewage treatment plant in D-67480 Edenkoben.
Date of collection: 06. Apr. 2018, batch no: 20180406.

Pre-Treatment
The sludge was filtrated through a cloth, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 3480 mg of suspended solids/L.

Duration of test (contact time):

28 d

Initial conc.:

23.1 - 23.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Preparations
The medium was prepared from the stock solutions. The stock solution of the positive con-trol was prepared and its DOC was measured. The inoculum was taken from its source, washed, aerated and the dry matter was determined.
The test vessels were filled with medium and inoculum. Then, all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2.
On the day of the start of the test, the aerated CO2-free medium and inoculum was filled into the test flasks prepared with a thin layer of test item.
7.2 Experimental Parameters
Flask volume: 1500 mL
Apparatus blanks 2, containing mineral medium only
Blank Controls 2, containing mineral medium and inoculum
Positive control flasks 2, containing positive control, mineral medium and inoculum
Test flasks 2, containing test item, mineral medium and inoculum
Abiotic control 1, containing test item, mineral medium and HgCl2
Toxicity control 1, containing test item, positive control, mineral medium and inoculum
Inoculum concentration: 25.0 mg/L
Temperature: 20.2 – 22.4 °C
Duration: 28 days
The test was performed with a nominal start concentration of 20 mg organic carbon/L test item.

Apparatus
The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, mois-tened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
Magnetic stirrers were used to prevent deposition of inoculum.
The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was separately determined in each flask.

Sampling
From each front scrubber flask, 10 samples were taken in order to determine the emitted CO2 (on day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29). The sample volume was 1 mL. The re-sulting change in the volume of the front flask was considered in the calculation of emitted CO2.
On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.

CO2 Determination
Analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena. Each sample was measured in duplicate or triplicate, respectively (depending on the variation between the measured values). The carbon ana-lyser was calibrated with freshly prepared reference solutions containing potassium hydro-gen phthalate (TC), sodium hydrogen carbonate and sodium carbonate (IC) every month. After every start, quality control samples were measured.

Reference substance:

aniline

Test performance:

All validity criteria were met.
Degradation behaviour of positive control and toxicity control was normal. Abiotic degrada-tion was not observed. Both replicates of the test item showed very good correspondence.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

18

Sampling time:

28 d

Details on results:

The test item Petroleum Resins (Kendex 0897) is considered as “not readily biode-gradable“.
The degree of biodegradation reached 18 % after 28 days.
The 10-day-window began on day 18, at its end, 18 % degradation were reached (graphic evaluation), missing the pass level of 60 % given in the OECD guideline.
Because the test item is a mixture, the 10-day window does not have to be taken into account. However, the test item is considered as “not readily biodegradable within 28 days”, either.
Abiotic degradation was not observed.

Results with reference substance:

Degradation of the positive control was 61 % after 11 days.

 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	2.22	3.40	2.49	2.63
2	4.23	5.39	9.88	9.87
4	5.72	7.10	15.61	24.39
7	8.45	9.89	22.11	34.15
9	10.29	11.85	35.26	43.80
11	11.84	14.04	40.28	54.78
14	13.72	16.59	44.19	69.94
18	15.50	21.12	54.23	79.39
23	19.01	26.27	63.22	83.27
29	25.72	33.12	74.10	101.28

 

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	2.29	2.61	2.48	2.41	2.50	2.69
2	15.15	12.73	11.49	16.29	7.70	23.91
4	38.45	52.96	30.46	28.66	9.21	68.74
7	142.52	123.29	42.37	42.80	10.63	226.14
9	196.97	211.45	61.18	57.36	12.03	270.53
11	230.59	247.51	68.47	70.07	13.42	308.69
14	268.18	273.64	81.18	85.04	14.83	348.09
18	304.35	309.96	101.37	99.67	16.72	373.86
23	321.60	317.47	117.02	113.71	18.67	392.80
29	372.06	368.96	152.34	144.56	23.66	430.28

 

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	2.73	2.65	1.93	2.44
29	5.53	2.72	4.75	3.63

 

IC values in mg/L of positive control, test flasks, back scrubber

Day	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	2.55	2.20	2.34	2.07	2.19	2.44
29	2.98	3.04	3.74	4.05	2.46	3.26

 

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

Day	Blank Control 1	Blank Control 2	Positive Control 1	Positive Control 2	Test 1	Test 2	Abiotic Control	Toxicity Control
0	2.5	2.6	2.3	2.6	2.5	2.4	2.5	2.7
2	7.9	7.9	13.2	10.7	9.5	14.3	5.7	21.9
4	12.9	20.8	34.9	49.4	26.9	25.1	5.6	65.1
7	15.9	27.9	136.3	117.1	36.2	36.6	4.4	219.9
9	27.0	35.5	188.7	203.2	52.9	49.1	3.8	262.3
11	30.2	44.7	220.5	237.4	58.3	59.9	3.3	298.6
14	31.8	57.6	255.8	261.3	68.8	72.7	2.5	335.7
18	38.7	63.9	288.9	294.5	85.9	84.2	1.2	358.4
23	43.4	63.4	301.8	297.6	97.2	93.9	-1.2	373.0
29	47.5	74.7	345.5	342.4	125.7	118.0	-3.0	403.7

 

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	1.9	2.4	2.6	2.2	2.3	2.1	2.2	2.4
29	3.3	2.2	1.5	1.6	2.3	2.6	1.0	1.8

 

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	7.8	7.8	7.9	7.9	7.8	7.8	7.2	7.9

 

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
2	0.36	0.35	0.72	0.54	0.46	0.78	0.21	1.27
4	0.68	1.19	2.13	3.05	1.59	1.48	0.20	4.08
7	0.87	1.64	8.67	7.40	2.18	2.21	0.12	14.05
9	1.57	2.11	11.93	12.84	3.23	2.99	0.08	16.61
11	1.75	2.66	13.82	14.87	3.54	3.64	0.05	18.74
14	1.84	3.44	15.89	16.21	4.16	4.40	0.00	20.87
18	2.25	3.80	17.77	18.09	5.17	5.07	-0.08	22.05
23	2.51	3.73	18.37	18.10	5.81	5.61	-0.22	22.71
29	2.82	4.35	20.75	20.57	7.47	7.05	-0.41	24.29

 

Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Toxicity Control
2	1.8	0.9	1.4	0.6	2.2	1.4	1.0	2.3
4	6.0	10.6	8.3	3.3	2.7	3.0	1.0	7.9
7	37.1	30.8	34.0	4.6	4.8	4.7	0.6	32.0
9	50.5	55.1	52.8	6.9	5.7	6.3	0.4	36.9
11	58.1	63.4	60.8	6.6	7.1	6.9	0.2	41.3
14	66.3	68.0	67.1	7.6	8.8	8.2	0.0	45.5
18	73.8	75.5	74.7	10.7	10.2	10.4	-0.4	47.5
23	76.4	75.0	75.7	13.4	12.4	12.9	-1.1	48.9
29	86.0	85.1	85.5	19.4	17.2	18.3	-2.0	51.7

 

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The following data were determined for the test item Petroleum Resins (Kendex 0897):
10-day-window: day 18 – 28
degradation at the end of 10-day-window 18 %
degradation at the end of the test 18 % pass level following guideline: 60 % at the end of 10-day-window for pure substances; respective 60 % at the end of the test for mixtures
Therefore, when applying the 10-day-window, the test item Petroleum Resins (Kendex 0897) is not readily biodegradable following OECD 301B and EU C.4-C respectively.
Because the test item is a mixture the 10-day-window does not have to be taken into ac-count. As degradation missed 60% in the course of the test, Petroleum Resins (Kendex 0897) is considered as not readily biodegradable.
However, at the end of the test no plateau of degradation was reached yet, indicating fur-ther biodegradation is possible.

Executive summary:

Determination of the aerobic ready biodegradability of Petroleum Resins (Kendex 0897) in the CO₂ Evolution Test following OECD 301B resp. EU C.4-C

 

Findings and Results:

The test item Petroleum Resins (Kendex 0897) was tested using a concentration of nominally 20 mg organic carbon/L (corresponding to 23.1 mg Petroleum Resins (Kendex 0897)/L) 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 was 61 % after 11 days.

 

The following data were determined for the test item Petroleum Resins (Kendex 0897):

10-day-window: day 18 – 28

degradation at the end of 10-day-window 18 %

degradation at the end of the test 18 %

pass level following guideline: 60 % at the end of 10-day-window for pure substances ; respective 60 % at the end of the test for mixtures

 

Therefore, when applying the 10-day-window, the test item Petroleum Resins (Kendex 0897) is not readily biodegradable following OECD 301B and EU C.4-C respectively.

Because the test item is a mixture the 10-day-window does not have to be taken into account. As degradation missed 60% in the course of the test, Petroleum Resins (Kendex 0897) is considered as not readily biodegradable.

However, at the end of the test no plateau of degradation was reached yet, indicating further biodegradation is possible.

Description of key information

When applying the 10-day-window, the test item Petroleum Resins (Kendex 0897) is not readily biodegradable following OECD 301B and EU C.4-C respectively.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The test item Petroleum Resins (Kendex 0897) was tested using a concentration of nominally 20 mg organic carbon/L (corresponding to 23.1 mg Petroleum Resins (Kendex 0897)/L) in test medium.

Degradation of the positive control was 61 % after 11 days.

 

The following data were determined for the test item Petroleum Resins (Kendex 0897):

10-day-window: day 18 – 28

degradation at the end of 10-day-window 18 %

degradation at the end of the test 18 %

pass level following guideline: 60 % at the end of 10-day-window for pure substances ; respective 60 % at the end of the test for mixtures

Therefore, when applying the 10-day-window, the test item Petroleum Resins (Kendex 0897) is not readily biodegradable following OECD 301B and EU C.4-C respectively.

Because the test item is a mixture the 10-day-window does not have to be taken into account. As degradation missed 60% in the course of the test, Petroleum Resins (Kendex 0897) is considered as not readily biodegradable.

However, at the end of the test no plateau of degradation was reached yet, indicating further biodegradation is possible.

[Type of water: freshwater]