Decanoic acid, mixed esters with dipentaerythritol, heptanoic acid and octanoic acid.

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:

31 March 2004 to 20 May 2004

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)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Source: The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: Waterschap de Maaskant', 's-Hertogenbosch, the Netherlands, receiving predominantly domestic sewage.
Treatment: The sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 3.8 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant). Before use, the sludge was allowed to settle (30-90 minutes) and the liquid decanted for use as inoculum at the amount of 10 ml/l of mineral medium.
Reason for selection: The test has been accepted internationally (EEC, OECD) for determining the 'ready' biodegradability of test substances under aerobic conditions

Duration of test (contact time):

28 d

Initial conc.:

18.5 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Test duration: 28 days (last CO2-measurement on the 29th day). During the test period aeration and stirring took place.
Test vessels: 2 litre all-glass brown coloured bottles.
Milli-RO / Milli-Q water: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ion­exchange cartridges (Milli-Q) (Millipore Corp., Bedford, Mass., USA).
Stock solutions of mineral components:
A) 8.50 g KH2PO4
21.75 g K2HPO4
67.20 g Na2HP04.12H20
0.50 g NH4CI
dissolved in Milli-Q water and made up to 1 litre pH 7.4+/-0.2
B) 22.50 g MgS04.7H20 dissolved in Milli-Q water and made upto 1litre.
C) 36.40 g CaCl2.2H20 dissolved in Milli-Q water and made up to 1litre
D)0.25 g FeCl3.6H20 dissolved in Milli-Q water and made up to 1litre.

Mineral medium: 1litre mineral medium contains: 10 ml of solution (A),
1 ml of solutians (B) to {D) and Milli-RO water.
Barium hydroxide: 0.0125 M, stored in a sealed vessel to prevent absorption of C02 from the air.
Synthetic air (C02 < 1 ppm): A mixture of oxygen (21%) and nitrogen (79%) was passed through a bottle, containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was sparged through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 ml/min).
Preparation of bottles
Pre-incubation medium: Mineral components, Milli-RO water (ca. 80% total volume) and inoculum (1% final volume) were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.
Type and number of bottles: Test suspension: containing test substance and inoculum (2 bottles).
Inoculum blank: containing only inoculum (2 bottles) Positive control: containing reference substance and inoculum (1 bottle).
Toxicity control: containing test substance, reference substance and inoculum (1 bottle).

Preparation: The test substance and positive control were added to the bottles containing the microbial organisms and mineral components (ca. 80% of total volume).
The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before.
Three C02-absorbers (bottles filled with 100 ml 0.0125 M Ba(OH)2) were connected in series to the exit air line of each test bottle.

Determination of CO2
Experimental CO2 production: The CO2 produced in each test bott1e reacted with the barium hydroxide ln the gas scrubbing bottle and precipitated out as barium carbonate. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCI.
Measurements: Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day. Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers was moved one position no the direction of the test bott1e. A new CO2-absorber was placed at the far end of the series. Phenolphthalein was used as pH-indicator.
On the 28th day, the pH of the test suspensions was measured and 1 ml of concentration HCI was added to each bottle. The bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 29.
Theoretical C02 production: The theoretical CO2 production was calculated from the molecular formula and the composition of linear fatty acids.

Measurements and recording
pH: At the start of the test and on the 28th day.
Temperature of the medium: Continuously in a vessel with Milli-Ro water in the same room.

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 77 - <= 80

Sampling time:

28 d

Remarks on result:

other: 60% degradation not reached within a 10 day window

Details on results:

Theoretical CO2 production
The Theoretical CO2 production (ThC02) of HATCOL 5127 was calculated to be 2.52 mg CO2/mg.
The concentration was 37.0 (A) and 36.7 mg (8) HATCOL 5127 in 2 litres test medium. Hence, the theoretical CO2 production following complete degradation was 93.2 mg per 2 litres for A and 92.5 mg per 2 litres for B.
The positive control contained 80.3 mg sodium acetate (ThCO2= 1.07 mg CO2/mg) resulting in a theoretical CO2 production following complete degradation of 85.9 mg per 2 litres.
The toxicity control contained 80.3 mg sodium acetate and 36.7 mg HATCOL 5127 in 2 litres of test medium. Hence, the theoretical CO2 production following complete degradation of HATCOL 5127 plus sodium acetate was 178.4 mg per2 litres.

Biodegradation:
The relative degradation values were calculated from the measures performed during the test period revealed 90-77% degradation of HATCOL 5127 for A and B, respectively. However, biodegradation of HATCOL 5127 of at least 60% was not reached within a 10-day window. Thus, the criterion for ready biodegradability were not met.
In the toxicity control more than 25% degradation occurred within 14 days (52% based on ThCO2). Therefore, the test substance was assumed to be not inhibitory to microbial activity.

Monitoring of temperature and pH: The temperature recorded in a vessel with water in the same room varies between 20.1 and 21.7˚C.

The pH values of the different test media were:

	Just before the start of the test	On day 28
Blank control (A)	7.6	7.6
Blank control (B)	7.6	7.6
Positive control	7.6	8.0
HATCOL 5127 (A)	7.6	7.6
HATCOL 5127 (B)	7.6	7.6
Toxicity control	7.6	7.9

 

CO2 production and percentage biodegradation of the positive control substance.

Day	HCL (0.05 N) titrated (ml)		Produced CO2 (ml HCL)	Produced CO2 (mg)	Cumulative CO2 (mg)	Degradation (%)*
	Blank (mean)	Positive control
0	-	-	-	-	-	0
2	48.68	35.15	13.53	14.9	14.9	17
5	46.62	28.15	18.47	20.3	35.2	41
7	45.07	33.12	11.95	13.1	48.3	56
9	43.50	35.00	8.50	9.3	57.7	67
14	47.02	38.73	8.29	9.1	66.8	78
19	44.58	38.06	6.52	7.2	74.0	86
23	44.35	41.82	2.53	2.8	76.7	89
27	46.46	42.96	3.50	3.8	80.6	94
29	44.06	42.04	2.02	2.2	82.8	96
29	44.28	43.96	0.32	0.4	83.2	97
29	45.58	46.29	0.00	0.0	83.2	97

*Calculated as the ratio between CO2 produced (cumulative) and the ThCO2 of sodium acetate 85.9 mg CO2/2l

 

CO2 production and percentage biodegradation of the test substance (bottle A)

Day	HCL (0.05 N) titrated (ml)		Produced CO2 (ml HCL)	Produced CO2 (mg)	Cumulative CO2 (mg)	Degradation (%)*
	Blank (mean)	Ts bottle A
0	-	-	-	-	-	0
2	48.68	46.30	2.38	2.6	2.6	3
5	46.62	38.34	8.27	9.1	11.7	13
7	45.07	32.22	12.85	14.1	25.9	28
9	43.50	34.12	9.38	10.3	36.2	39
14	47.02	30.85	16.17	17.8	53.9	58
19	44.58	34.39	10.19	11.2	65.2	70
23	44.35	40.25	4.10	4.5	69.7	75
27	46.46	42.31	4.15	4.6	74.2	80
29	44.06	43.65	0.41	0.5	74.7	80
29	44.28	44.63	0.0	0.0	74.7	80
29	45.58	45.77	0.0	0.0	74.7	80

*Calculated as the ratio between CO2 produced (cumulative) and the ThCO2 of the test substance: 93.2 mg CO2/2l

Comparison of biodegradation of the test substance in bottles A and B

Day	Biodegradation (%)
	Bottle A	Bottle B	Mean A & B	A-B*
0	0	0	0	0
2	3	3	3	0
5	13	14	13	1
7	28	26	27	2
9	39	35	37	4
14	58	55	56	3
19	70	67	69	2
23	75	72	74	2
27	80	77	78	3
29	80	77	79	3
29	80	77	79	3
29	80	77	79	3

*Absolute difference in biodegradation between bottles A and B

 

CO2 production and percentage biodegradation of the toxicity control

Day	HCL (0.05 N) titrated (ml)		Produced CO2 (ml HCL)	Produced CO2 (mg)	Cumulative CO2 (mg)	Degradation (%)*
	Blank (mean)	Toxicity control
0	-	-	-	-	-	0
2	48.68	39.28	9.40	10.3	10.3	6
5	46.62	24.95	21.67	23.8	34.2	19
7	45.07	25.91	19.16	21.1	55.2	31
9	43.50	27.43	16.07	17.7	72.9	41
14	47.02	28.72	18.30	20.1	93.0	52
19	44.58	32.65	11.93	13.1	106.2	60
23	44.35	37.12	7.23	8.0	114.1	64
27	46.46	42.39	4.07	4.5	118.6	66
29	44.06	39.11	4.95	5.4	124.0	70
29	44.28	42.90	1.38	1.5	125.5	70
29	45.58	46.13	0.00	0.0	125.5	70

*Calculated as the ration between CO2 produced (cumulative) and the sum of the ThCO2 of the test substance and positive control: 178.4 mg CO2/2l

ThC02 test substance: 92.5 mg CO2/21

ThC02 sodium acetate: 85.9 mg C02/2I

CO2 production on the blank

 

CO2 production on the blank

Day	HCL (0.05 N) titrated (ml)		Produced CO2 (ml HCL)	Produced CO2 (mg)	Cumulative CO2 (mg)
	Blank (mean)	Toxicity Ba(OH)2*
0	-	-	-	-	-
2	48.68	50.00	1.32	1.5	1.5
5	46.62	49.69	3.08	3.4	4.8
7	45.07	49.82	4.76	5.2	10.1
9	43.50	48.59	5.10	5.6	15.7
14	47.02	50.97	3.95	4.3	20.0
19	44.58	49.91	5.33	5.9	25.9
23	44.35	49.51	5.16	5.7	31.5
27	46.46	50.42	3.97	4.4	35.9
29	44.06	49.64	5.58	6.1	42.0
29	44.28	47.91	3.63	4.0	46.0
29	45.58	47.05	1.47	1.6	47.6
0	0	0	0	0	47.6

Strength of untreated 0.0125 M (Ba(OH)2 solution

 

 

 

 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

HATCOL 5127 was degraded significantly (80 and 77%) during the test period. However, since at least 60% biodegradation was not reached within ten days of biodegradation exceeding 10%, the criterion for ready biodegradability was not met. Thus, under the conditions of this test
HATCOL 5127is regarded as readily biodegradable but failing the 10 -day window.

Executive summary:

Determination of 'ready' biodegradability: carbon dioxide (CO2) evolution test (modified Sturm test) with HATCOL 5127.

The study procedure was based EEC directive 92/69, C.4-C, December 1992, and OECD guideline No. 301 B July 17, 1992.

The Theoretical C02 production (ThC02) of HATCOL 5127 was calculated to be 2.52 mg CO2/mg.

HATCOL 5127 is a light yellow liquid and treated as 100% pure. The water solubility of Hatcol 5127 at 20.4 +/- 0.7˚C is < 0.14x10^-1 g/l (the pH was between 8.0-8.1, “NOTOX Project 388035 Determination of the Water solubility of HATCOL 5127").

ln the study present1y performed HATCOL 5127 was tested in duplicate at 37 mg per 2 litres, corresponding to 13 mg TOC/l. The organic carbon content was based on the molecular formula and the composition of linear fatty acids (34% C7, 38% CB and 25% C1 ;סC6 and C12 were not used for calculations).

The study consisted of six bottles:

2 blank controls (no test material)

2 test bottles (HATCOL 5127 – 18.5 mg/L)

1 positive control (sodium acetate -40 mg/L)

1 toxicity control (HATCOL 5127 – 18.5 mg/L; place sodium acetate 40 mg/L)

 

Since HATCOL 5127 was poorly soluble in water, weighed amounts of HATCOL 5127 were added to the test bottles containing medium with microbial organisms and mineral components. 10 ml of milli-RO water was added to each weighing bottle. After vigorous shaking the resulting suspension was added quantitatively to the test medium. The test solutions were continuously stirred during the test, to ensure optimal contact between the test substance and the test organisms.

The relative degradation values calculated from the measurements performed during the test period revealed 80 and 77% degradation of HATCOL 5127 for A and B, respectively. However, biodegradation of HATCOL 5127 of at least 60% was not reached within a 10-day window.

Thus, the criterion for ready biodegradability was not met.

In the toxicity control HATCOL 512

Was found not to inhibit microbial activity.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

In conclusion, HATCOL 5127 is regarded as readily biodegradable but failing the 10 -day window.

Description of key information

HATCOL 5127 was degraded significantly (80 and 77%) during the test period. However, since at least 60% biodegradation was not reached within ten days of biodegradation exceeding 10%, the criterion for ready biodegradability was not met. As specified by R.11.4.1.1.3 Test data on biodegradation the 10-day window need not apply to UVCB substances where studies have been conducted to OECD TG 301 A-F. Thus, under the conditions of this test HATCOL 5127 is regarded as readily biodegradable but failing the 10 -day window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window

Type of water:

freshwater

Additional information

Determination of 'ready' biodegradability: carbon dioxide (CO2) evolution test (modified Sturm test) with HATCOL 5127.

The study procedure was based EEC directive 92/69, C.4-C, December 1992, and OECD guideline No. 301 B July 17, 1992.

The Theoretical C02 production (ThC02) of HATCOL 5127 was calculated to be 2.52 mg CO2/mg.

HATCOL 5127 is a light yellow liquid and treated as 100% pure. The water solubility of Hatcol 5127 at 20.4 +/- 0.7˚C is < 0.14x10^-1 g/l (the pH was between 8.0-8.1, “NOTOX Project 388035 Determination of the Water solubility of HATCOL 5127").

ln the study present1y performed HATCOL 5127 was tested in duplicate at 37 mg per 2 litres, corresponding to 13 mg TOC/l. The organic carbon content was based on the molecular formula and the composition of linear fatty acids (34% C7, 38% CB and 25% C1 ;סC6 and C12 were not used for calculations).

The study consisted of six bottles:

2 blank controls (no test material)

2 test bottles (HATCOL 5127 – 18.5 mg/L)

1 positive control (sodium acetate -40 mg/L)

1 toxicity control (HATCOL 5127 – 18.5 mg/L; place sodium acetate 40 mg/L)

 

Since HATCOL 5127 was poorly soluble in water, weighed amounts of HATCOL 5127 were added to the test bottles containing medium with microbial organisms and mineral components. 10 ml of milli-RO water was added to each weighing bottle. After vigorous shaking the resulting suspension was added quantitatively to the test medium. The test solutions were continuously stirred during the test, to ensure optimal contact between the test substance and the test organisms.

The relative degradation values ca1culated from the measurements performed during the test period revealed 80 and 77% degradation of HATCOL 5127 for A and B, respectively. However, biodegradation of HATCOL 5127 of at least 60% was not reached within a 10-day window.

Thus, the criterion for ready biodegradability was not met.

In the toxicity control HATCOL 512

Was found not to inhibit microbial activity.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

In conclusion, HATCOL 5127 was

is regarded as readily biodegradable but failing the 10 -day window.