Decanoic acid, mixed esters with heptanoic acid, isovaleric acid, octanoic acid and pentaerythritol

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:

09. Oct. 2017 to 08. Nov. 2017

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:

yes

Remarks:

See "Any other information" for details

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

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

Deviations:

yes

Remarks:

See "Any other information" for details

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: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 06. Oct. 2017, batch no: 20171006.
Pre-Treatment: The sludge was filtrated, washed with tap water (2x), then washed with and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 4520 mg of suspended solids/L.

Duration of test (contact time):

28 d

Initial conc.:

>= 31.3 - <= 32 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Pre-Treatment-Test material
The carbon content of 64.00 % was determined by elemental analysis under non-GLP conditions, performed at the accredited laboratory Mikroanalytisches Labor Pascher, An der Pulvermühle 1, D-53424 Remagen, Germany. The test item was added directly, the amounts were calculated from the carbon content of the test item.

Positive Control
Aniline (Phenylamine, C6H5NH2, CAS-No. 62-53-3) was used as a readily bio-degradable positive control. A stock solution containing 2103.2 mg/L in deionised water was prepared and its organic carbon content was measured with 1727.2 mg/L, corresponding to an organic carbon content of the positive control of 82.1 %.

Test Vessels
2000 mL-SCHOTT-flasks were used as test vessels, 100 mL scrubber flasks as absorbent vessels.

PERFORMANCE OF THE STUDY
Preparations
The medium was prepared from stock solutions. The stock solution of the positive control 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.

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: 19.4 – 21.5 °C
Duration: 28 days
The test was performed with a nominal start concentration of 20 mg organic carbon/L.

Apparatus
The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened 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.

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

78

Sampling time:

28 d

Details on results:

The test item Hatcol 1570 is considered as “readily biodegradable“.
- The degree of biodegradation reached 78 % after 28 days.
- The 10-day-window began on day 3, at its end, 56 % degradation were reached, missing the pass level of 60 % given in the OECD guideline.
- Because the test item is a mixture, the 10-day window has not to be taken into account. Therefore, regardless of the 10-day-window the test item is considered as “readily biodegradable within 28 days”.
- Abiotic degradation was not observed.

IC-Values

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

 

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	3.20	3.63	3.02	2.90
2	4.60	3.92	16.01	7.81
4	4.25	4.73	22.34	12.98
7	5.32	6.87	29.10	23.19
10	8.24	10.04	38.89	31.24
14	11.22	12.93	48.77	46.71
18	15.14	15.28	50.08	44.89
24	19.38	19.71	60.93	57.02
29	25.80	26.20	71.24	65.37

 

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	4.64	2.80	3.02	2.87	3.21	2.88
2	13.33	10.11	7.66	10.11	6.12	14.03
4	29.31	50.29	104.33	55.27	7.03	119.17
7	225.85	173.55	159.15	94.50	8.28	323.23
10	252.37	251.90	207.68	144.54	10.15	415.06
14	309.85	306.93	278.78	197.03	12.51	525.06
18	317.54	317.56	287.45	251.582	13.28	535.77
24	351.23	344.49	336.28	308.88	16.60	584.19
29	348.97	339.54	329.80	321.24	20.99	579.69

 

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

 

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	3.62	2.78	3.10	2.84
29	4.53	3.87	3.25	4.06

 

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	2.92	3.02	3.03	2.71	3.05	2.95
29	3.28	7.76	4.16	3.38	4.04	3.83

 

Net IC

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

 

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	3.0	2.9	4.6	2.8	3.0	2.9	3.2	2.9
2	15.2	7.0	12.5	9.3	6.8	9.3	5.3	13.2
4	21.3	11.9	28.2	49.2	103.3	54.2	6.0	118.1
7	26.4	20.5	223.2	170.9	156.5	91.8	5.6	320.6
10	33.2	25.5	246.6	246.2	202.0	138.8	4.4	409.3
14	40.1	38.1	301.2	298.3	270.1	188.4	3.9	516.4
18	38.3	33.1	305.7	305.8	275.7	239.7	1.5	524.0
24	44.8	40.9	335.1	328.4	320.2	292.8	0.5	568.1
29	48.7	42.8	326.4	317.0	307.2	298.7	-1.6	557.1

 

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	3.1	2.8	2.9	3.0	3.0	2.7	3.1	3.0
29	2.3	3.1	2.3	6.8	3.2	2.4	3.0	2.8

 

Negative values occur, when the apparatus blank was higher than the respective treatment. As the measured values in these blanks as well as in the abiotic control are very low, measurement uncertainties lead to negative degradation values in the abiotic control.

 

pH

In the following table, the pH at the end of the test (before addition of HCI) is given:

pH in Test flasks in 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	7.3	7.3	7.4	7.4	7.0	7.5

 

 

Calculation Results

 

Emitted Carbon in mg/L

In the following table, the calculated emitted carbon (from net IC) is presented.

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	0.80	0.27	0.52	0.43	0.25	0.42	0.14	0.68
4	1.19	0.59	1.54	3.03	6.55	3.35	0.18	7.53
7	1.51	1.14	14.13	10.87	9.92	5.75	0.15	20.54
10	1.93	1.45	15.49	15.58	12.73	8.70	0.08	26.01
14	2.35	2.23	18.78	18.71	16.92	11.75	0.04	32.52
18	2.21	1.89	18.87	18.99	17.09	14.84	-0.11	32.66
24	2.59	2.36	20.49	20.18	19.66	17.97	-0.17	35.04
29	2.74	2.46	19.69	19.52	18.67	18.12	-0.30	33.98

 

Degradation Values

In the following table, the percentage biodegradation is presented:

Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Toxicity Control
2	-0.1	-0.5	-0.3	-1.4	-0.6	-1.0	0.7	0.4
4	3.3	10.7	7.0	28.3	12.0	20.2	0.9	16.5
7	63.9	47.6	55.8	43.0	21.6	32.3	0.8	47.8
10	68.9	69.3	69.1	55.2	34.2	44.7	0.4	60.5
14	82.3	82.0	82.2	73.1	46.2	59.6	0.2	75.2
18	83.9	84.5	84.2	75.1	62.5	68.8	-0.5	76.1
24	89.9	88.4	89.2	85.9	75.7	80.8	-0.9	81.0
29	85.3	84.4	84.9	80.3	75.8	78.0	-1.5	78.0

 

Because the values of day 29 are the sum of the IC values 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 abiotic control are very low, measurement uncertainties lead to negative degradation values while in fact no degradation has taken place.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

When applying the 10-day-window, Hatcol 1570 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 surpassed 60% in the course of the test, Hatcol 1570 is considered as readily biodegradable.

Executive summary:

The test item Hatcol 1570 was tested using a concentration of nominally 20 mg organic carbon/L (corresponding to 31.3 mg Hatcol 1570/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 69 % after 10 days.

 

The following data were determined for the test item Hatcol 1570:

10-day-window: day 3 – 13

degradation at the end of 10-day-window: 56 %

degradation at the end of the test: 78 %

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

 

Therefore, when applying the 10-day-window, Hatcol 1570 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 surpassed 60% in the course of the test, Hatcol 1570 is considered as readily biodegradable.

Description of key information

As degradation surpassed 60% in the course of the test, Hatcol 1570 is considered as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The test item Hatcol 1570 was tested using a concentration of nominally 20 mg organic carbon/L (corresponding to 31.3 mg Hatcol 1570/L) in test medium.

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.

 

The following data were determined for the test item Hatcol 1570:

10-day-window: day 3 – 13

degradation at the end of 10-day-window: 56 %

degradation at the end of the test: 78 %

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

Therefore, when applying the 10-day-window, Hatcol 1570 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 surpassed 60% in the course of the test, Hatcol 1570 is considered as readily biodegradable.