Reaction mass of 1-[rac-(1R,6S)-2,2,6-trimethylcyclohexyl]pentan-3-ol isomer 1 and 1-[rac-(1S,6S)-2,2,6-trimethylcyclohexyl]pentan-3-ol

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:

from 2012-05-17 to 2012-07-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Guidelines for the testing of chemicals, SEPA, P.R. China No. 301C "Modified MITI Test (I)" 2004

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.4-F (Determination of the "Ready" Biodegradability - MITI Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Samples form ten sites were collected, mainly areas where a variety of chemicals were used and discharged. The sites included sewage treatment plants. industrial wastewater treatment plants, rivers, lakes, seas. 1 L sample of sludge, surface soil, water and etc. was collected and then mixed together.
After removal of the floating matter and settling, the pH of the supernatant was measured to be 7. The supernatant was colelcted and aerated for 23.5 h. 30 minutes after the aeration was stopped, 1/3 of the supernatant was discarded. Then equal volume of solution containig 0.1 % of glucosem peptonem potassium prthophosphate was added and the aeration was continued. This procedure was repeated once a day for a month. The temperature was kept at 25 ± 1 °C and the pH at 7 ± 1. After one month the sludge was used as microbial inoculum. Before the start of the test a small amount waa dried to determined the wet weight of the sludge.

The inoculum concentration used for the test was 30 mg SS/L.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

- 1 bottle with the test item in deionised water as abiotic control
- 3 bottles with test item and inoculum
- 1 bottle with reference item and inoculum as procedure control
The test was performed in complete darkness.
The tets system was placed in an incubator at a temperature of 20 ± 1 °C.
- 1 bottle only with inoculum as inoculum control

Reference substance:

aniline

Key result

Parameter:

% degradation (TOC removal)

Value:

30.85

Sampling time:

28 d

Details on results:

The theoretical oxygen uptake of the test item was 3.09 mg O1/mg test item. Within 28-day test period, the cumulated % biodegradation of the test item was 30.85 %, % abiotic degradation was 27.27 % and % primary degradation was 7.12 % based on TOC calculation.

Results with reference substance:

The cumulated % biodegradation of the reference substance after 28 days was 81.74 %.

Table 1. Biodegradation results of the test item (28 days)

Time (d)	Cumulative BOD (mg/L)					BOD (mg O2/mg test item)	Cumulative percentage biodegradation (%)
	Abiotic control	Inoculum control (IC)	Test item (TI)
	BIC	IC	TI-1	TI-2	TI-3
1	0	0	0	0	0	0.00	0.00
2	1	0	2	1	1	0.01	0.43
3	3	0	6	7	6	0.06	2.05
4	6	0	12	14	17	0.14	4.64
5	17	1	21	23	28	0.23	7.44
6	37	1	44	47	45	0.44	14.35
7	68	2	57	55	62	0.56	18.12
8	70	3	69	68	74	0.67	21.79
9	71	4	89	89	87	0.84	27.29
10	72	6	92	91	91	0.85	27.62
11	75	6	97	94	93	0.89	28.69
12	76	7	98	96	94	0.89	28.80
13	77	8	99	97	96	0.89	28.91
14	78	10	102	100	96	0.89	28.91
15	80	10	103	101	97	0.90	29.23
16	81	10	103	103	99	0.92	29.67
17	81	11	104	104	100	0.92	29.67
18	82	11	105	105	100	0.92	29.88
19	83	12	106	106	101	0.92	29.88
20	84	13	107	107	102	0.92	29.88
21	85	14	108	108	103	0.92	29.88
22	86	14	108	108	104	0.93	29.99
23	87	15	109	109	105	0.93	29.99
24	89	15	110	110	106	0.94	30.31
25	90	16	111	111	107	0.94	30.31
26	91	16	111	112	108	0.94	30.53
27	92	17	112	113	109	0.94	30.53
28	92	17	113	114	110	0.95	30.85

Note: BIC means abiotic control, IC means Inoculum Control, TI means Test Item.

Analytical results

TOC Analyzer was used to determined the total organic carbon in the samples. The Limit of Detection (LOD) was 0.280 µg C and the limit of quantitation was 1.12 µg C.

The TOC of the test item in solutions in reaction bottles were measured at thebeginning and the end of the test. Prior to the TOC measurement, the solutions wereoscillated for 10 min using ultrasonication to ensure homodisperse.

Table 2. TOC concentrations of the test item in solutions

No. of bottles	Beginning of the test	End of the test
1 (BIC)	62.46	45.64
2 (TI-1)	64.55	43.03
3 (TI-2)	65.86	42.34
4 (TI-3)	63.75	42.54
5 (PC)	/	/
6 (IC)	1.36	1.20

Note: the carbon content of the test item was calculated to be 79.25%.

 

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The test item showed 31 % biodegradation in a Modified MITI Test. Therefore, the test item is considered to be not readily biodegradable, but inherently biodegradable as more than 20 % biodegradation was observed.

Executive summary:

The ready biodegradability of the test item was determined with an activated sludge over a test period of 28 days in the Modified MITI Test (I) according to OECD 301C, Regulation (EC) No. 440/2008 Method C.4-F and Guidelines for the testing of chemicals, SEPA, P.R. China No. 301C "Modified MITI Test (I)" 2004. The test item was tested at a concentration of 100 mg/L in triplicates, corresponding to carbon content of 79.25 % and theoretical oxygen uptake of 3.09 mg O2/mg test item. The total organic carbon was measured with TOC Analyzer. The biodegradation of the test item came to 30.85 % after 28 days. The reference item showed 81.74 % degradation after 28 days. In conclusion, the test item is not readily biodegradable as the pass level of 60 % degradation was not reached in a 10-d-window within the 28 days period of the study. As more than 20 % biodegradation was observed, the test item can be cosidered as inherently biodegradable.

Description of key information

The test item degraded to 31 % in the modified MITI test. Based on this results, the test item is considerd as not readily biodegradable. As the test item showed more than 20 % biodegradation in the MITI test, the test item can be cosidered as inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, fulfilling specific criteria

Additional information

The ready biodegradability of the test item was determined with an activated sludge over a test period of 28 days in the Modified MITI Test (I) according to OECD 301C, Regulation (EC) No. 440/2008 Method C.4-F andGuidelines for the testing of chemicals, SEPA, P.R. China No. 301C "Modified MITI Test (I)" 2004. The test item was tested at a concentration of 100 mg/L in triplicates, corresponding to carbon content of79.25 % and theoretical oxygen uptake of 3.09 mg O2/mg test item.The total organic carbon was measured with TOC Analyzer. The biodegradation of the test item came to 30.85 % after 28 days. The reference item showed 81.74 % degradation after 28 days. In conclusion, the test item is not readily biodegradable as the pass level of 60 % degradation was not reached in a 10-d-window within the 28 days period of the study.

In conclusion, the test item is not readily biodegradable. As more than 20 % biodegradation were observed in the MITI test, the test item can be cosidered as inherently biodegradable.

[Type of water: freshwater]

[Type of water: freshwater]