3-hydroxypropyl octanoate

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:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

17 July 1992

Deviations:

no

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: Beijing Xiaojiahe Sewage Treatment Work

- Pretreatment: The activated sludge was washed 3 times in the mineral medium through centrifugation (at 1100 g for 10 minutes). Thereafter the sludge was aerated before using. The aerated sludge was kept under test condition for about 5 days. After the pre-conditioning of inoculum, the sample was withdrawn just before using to measure the dry weight of the suspended solid.

Duration of test (contact time):

28 d

Initial conc.:

21.1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 21.1 – 22.8℃
- pH: 7.42 – 7.52
- pH adjusted: no
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: BOD bottle (volume: approx. 500 mL)
- Number of culture flasks/concentration: 2
- Measuring equipment: BOD meter
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: data on oxygen uptake was collected every 24 hours. During the test, the temperature of incubator was supervised daily and recorded. At the start and end of test, the pH of the contents of the bottles was measured.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Procedure control: yes
- Toxicity control: yes
- Test suspension: yes

STATISTICAL METHODS: Data was summarized in tabular form, showing percentage biodegradation of test group and procedure control. The difference of extremes of replicate values of the percentage degradation of test substance at the end of the test and the percentage degradation in 14 days of toxicity control were calculated using Excel.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

no

Test performance:

164 mL inoculum blank / test suspension / procedure control / toxicity control solution was put into the test bottle, and the BOD equipment was assemble, the equipment check if it was air-tight, the stirrer was started, and the measurement of oxygen uptake was started. The developed CO2 was captured using excess NaOH. The test bottles were placed in incubator and kept in the dark except during observation for 28 days. Oxygen uptake and temperature was measured daily. At the start and end of test, the pH of the contents of the bottles was measured.

Key result

Parameter:

% degradation (O2 consumption)

Value:

82.74

Sampling time:

28 d

Details on results:

The average biodegradation on the 1st day was 32.31%, which was over 10%, so the 10-d window was fulfilled between 1-11 days. The percentage biodegradation of the test substance was 80.10% on day 11. It has reached the pass level of ready biodegradation (60% ThOD). On the 28th day, the average percentage biodegradation reached to 82.74%.

The details of percentage biodegradation are presented in Table 1 in the section “Any other information on results incl. tables”.

Results with reference substance:

The average biodegradation at the 1st day after exposure was 53.52 %, which was over 10%, so it has entered the 10-day window period. The average biodegradation increased to 87.28 % on day 14, it meant it reached pass level of ready biodegradation (60 %ThOD). On the 28th day after exposure, the average biodegradation reached to 87.13 %.

Table 1: The Determination of oxygen consumption and percentage biodegradation

Group	Beaker No.	Day
		1	2	3	4	5	6	7	8	9	10	11	12	13	14
		BOD (mg/L)
TB (inoculum blank)	1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	2.8	5.6	2.8	8.4	8.4	8.4	11.3
	2	0.0	0.0	0.0	0.0	0.0	0.0	0.0	2.8	5.6	5.6	5.6	5.6	8.4	8.4
TS (test suspension)	3	33.8	50.6	59.1	61.9	67.5	73.2	76.0	78.8	81.6	84.4	87.2	90.0	92.8	92.8
	4	30.9	50.6	56.3	64.7	67.5	73.2	76.0	78.8	81.6	84.4	87.2	90.0	90.0	90.0
	Biodegradation (%)	32.31	50.54	57.63	63.22	67.41	73.11	75.90	75.90	75.90	80.10	80.10	82.89	82.89	81.45
PC (procedure control)	5	53.5	64.7	67.5	70.3	73.2	78.8	81.6	84.4	87.2	87.2	90.0	92.8	95.7	95.7
	6	53.5	61.9	67.5	70.3	73.2	78.8	81.6	84.4	87.2	90.0	92.8	95.7	95.7	98.5
	Biodegradation (%)	53.52	63.32	67.52	70.33	73.23	78.83	81.63	81.63	81.63	84.43	84.43	87.28	87.33	87.28
TC (toxicity control)	7	50.6	95.7	110	118	127	132	138	143	149	152	155	160	163	166
	Biodegradation (%)	-	-	-	-	-	-	-	-	-	-	-	-	-	78.04

Continued from Table 1：

 

Group	Beaker No.	Day
		15	16	17	18	19	20	21	22	23	24	25	26	27	28
		BOD (mg/L)
TB (inoculum blank)	1	11.3	11.3	11.3	14.1	11.3	14.1	14.1	14.1	14.1	16.9	16.9	16.9	16.9	16.9
	2	8.4	8.4	11.3	11.3	11.3	11.3	11.3	14.1	14.1	14.1	14.1	14.1	16.9	16.9
TS (test suspension)	3	92.8	92.8	92.8	95.7	95.7	95.7	95.7	95.7	98.5	98.5	98.5	98.5	98.5	98.5
	4	92.8	92.8	92.8	95.7	95.7	95.7	98.5	98.5	98.5	98.5	98.5	101	98.5	101
	Biodegradation (%)	82.84	82.84	81.40	82.89	84.29	82.89	84.29	82.89	84.29	82.89	82.89	84.14	81.50	82.74
PC (procedure control)	5	95.7	95.7	98.5	98.5	98.5	98.5	98.5	98.5	98.5	101	101	101	101	104
	6	98.5	98.5	101	101	101	101	98.5	101	101	101	104	104	104	104
	Biodegradation (%)	87.28	87.28	88.48	87.08	88.48	87.08	85.83	85.68	85.68	85.53	87.03	87.03	85.63	87.13
TC (toxicity control)	7	166	169	169	172	172	174	177	177	177	174	174	174	180	180
	Biodegradation (%)	-	-	-	-	-	-	-	-	-	-	-	-	-	-

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In a study according OECD 301F, the result showed that the percentage biodegradation of the test item was 80.10 % at the end of the 10-d window, so the test item is regarded as readily biodegradable.

Executive summary:

The ready biodegradability of the test item was determined by measuring the percentage biodegradation of inoculum to the test item over a period of 28 days in a study according to  OECD Test Guideline 301 (F), Ready Biodegradability-Manometric Respirometry Test, 17 July 1992 and The Guidelines for the Testing of Chemicals-degradation and accumulation(second) 301. The activated sludge was washed 3 times in the mineral medium through centrifugation (at 1100 g for 10 minutes). Thereafter the sludge was aerated before using. The aerated sludge was kept under test condition for about 5 days. After the pre-conditioning of inoculum, the sample was withdrawn just before using to measure the dry weight of the suspended solid. This test was set in one treatment group at the concentration of 21.10 mg test item /L (corresponding to a ThOD_NH3 of 100 mg O2/L) with 2 replications, blank control group with 2 replications and procedure control group at the concentration of 60.02 mg reference item /L (corresponding to a ThOD of 100 mg O₂/L) with 2 replications, the toxicity control group at the concentration of 21.10 mg test item /L(corresponding to a ThOD_NH3 of 100 mg O₂/L) and 60.02 mg reference item /L (corresponding to a ThOD of 100 mg O₂/L) without repeat and tested in BOD-bottles at the test condition for 28 days. All validity criteria were met. The maximum oxygen uptake of the inoculum blank was 16.9 mg/L in 28 days that wasn’t greater than 60 mg/L. For the procedure control, the average biodegradation increased to 87.28% on day 14, which means it reached pass level of ready biodegradation (60%ThOD). For the toxicity control test, the result showed that the biodegradation increased to 78.04% (more than 25%) on the 14th day, so the test substance can’t be assumed to be inhibitory. The result showed that the percentage biodegradation of the test item was 80.10 % at the end of 10-d window (1 day – 11 day) and 82.74 % at the end of the test (28 day), thus the test item is regarded as readily biodegradable.

Description of key information

The percentage biodegradation of the test item was 80.10 % at the end of the 10-d window, so the test item is regarded as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of the test item was determined by measuring the percentage biodegradation of inoculum to the test item over a period of 28 days in a study according to  OECD Test Guideline 301 (F), Ready Biodegradability-Manometric Respirometry Test, 17 July 1992 and The Guidelines for the Testing of Chemicals-degradation and accumulation (second) 301. The activated sludge was washed 3 times in the mineral medium through centrifugation (at 1100 g for 10 minutes). Thereafter the sludge was aerated before using. The aerated sludge was kept under test condition for about 5 days. After the pre-conditioning of inoculum, the sample was withdrawn just before using to measure the dry weight of the suspended solid. This test was set in one treatment group at the concentration of 21.10 mg test item /L (corresponding to a ThOD_NH3 of 100 mg O2/L) with 2 replications, blank control group with 2 replications and procedure control group at the concentration of 60.02 mg reference item /L (corresponding to a ThOD of 100 mg O₂/L) with 2 replications, the toxicity control group at the concentration of 21.10 mg test item /L(corresponding to a ThOD_NH3 of 100 mg O₂/L) and 60.02 mg reference item /L (corresponding to a ThOD of 100 mg O₂/L) without repeat and tested in BOD-bottles at the test condition for 28 days.

All validity criteria were met. The maximum oxygen uptake of the inoculum blank was 16.9 mg/L in 28 days that wasn’t greater than 60 mg/L. For the procedure control, the average biodegradation increased to 87.28% on day 14, which means it reached pass level of ready biodegradation (60% ThOD). For the toxicity control test, the result showed that the biodegradation increased to 78.04% (more than 25%) on the 14th day, so the test substance can’t be assumed to be inhibitory. The result showed that the percentage biodegradation of the test item was 80.10 % at the end of 10-d window (1 day – 11 day) and 82.74 % at the end of the test (28 day), thus the test item is regarded as readily biodegradable.