2,5-di-tert-butyl-p-benzoquinone

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:

29.09.2017-28.12.2017

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)

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Yasho Indutries Pvt. Ltd. / 20016011417
- Expiration date of the lot/batch: June 2019
- Purity test date: July 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: forms a suspension in mineral medium at 200 mg/L
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: not specified

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: not specified

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, adapted

Details on inoculum:

- Source of inoculum (e.g. location, sampling depth, contamination history, procedure): Sewage Treat
ment Plant Bengaluru - 560058 India
- Storage conditions: at room temperature, aerated
- Storage length: 5 days
- Preparation of inoculum for exposure: The effluent was allowed to settle for one hour, decanted
and the decanted effluent was used in the test
- Initial cell/biomass concentration: 6.0 x 10^7 CFU/L
- Water filtered: no

Duration of test (contact time):

29 d

Initial conc.:

>= 10 - <= 20 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mixture of 24 mL of stock solution A with 1920 mL of Milli-Q water, then 2.4
mL each of stock solutions B, C and D was added and finally the volume was made up to 2400 mL
using Milli-Q water (See tables)
- Test temperature: 21-24 C
- pH: approx. 7.8
- pH adjusted: no
- Aeration of dilution water: with CO2 free air
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Conical flask 5 L - each fitted with an aeration tube reaching nearly to the botto
m of the flask and an outlet
- Number of culture flasks/concentration: 2 / 10-20 mg/L
- Method used to create aerobic conditions: The flasks were aerated with CO2 free air at 46 to 50 mL
/minute
- Test performed in closed vessels due to significant volatility of test substance: no
- Details of trap for CO2 and volatile organics if used:

SAMPLING
- Sampling frequency: Days 2, 4, 7, 9, 12, 15, 17, 21, 25 and 29
- Sampling method: the CO2 was trapped in barium hydroxide and was measured by titration of the
residual hydroxide or as inorganic carbon

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 flasks
- Toxicity control: yes

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 18.35

St. dev.:

3.274

Sampling time:

7 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 55.76

St. dev.:

2.857

Sampling time:

17 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 66.18

St. dev.:

1.068

Sampling time:

21 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 104.44

St. dev.:

5.176

Sampling time:

29 d

Table 1: Carbon dioxide production

Day	CO2 Produced (mg)							Cumulative CO2 produced (mg) Test - Blank Mean
	Test Flasks				Blank
	Flask 1	Flask 2	Flask 5	Flask 6	Flask 3	Flask 4	Mean	Flask 1	Flask 2	Flask 5	Flask 6
Day 2	17.49	18.26	23.54	18.81	9.13	8.91	9.02	8.47	9.24	14.52	9.79
Day 4	19.69	22.44	32.45	26.07	14.63	16.61	15.62	12.54	16.06	31.35	20.24
Day 7	25.96	30.25	40.92	31.02	12.21	10.78	11.5	27	34.81	60.77	39.76
Day 9	29.15	28.49	43.12	34.54	11.22	13.97	12.6	43.55	50.7	91.29	61.7
Day 12	34.98	36.41	37.18	34.1	14.85	11.11	12.98	65.55	74.13	115.49	82.82
Day 15	30.03	25.96	26.84	39.82	10.89	8.47	9.68	85.9	90.41	132.65	112.96
Day 17	20.35	22.66	32.23	34.98	16.94	14.52	15.73	90.52	97.34	149.15	132.21
Day 21	32.12	27.83	26.84	25.63	10.78	14.08	12.43	110.21	112.74	163.56	145.41
Day 25	53.35	53.02	20.9	31.79	13.75	12.98	13.37	150.19	152.39	171.09	16.83
Day 29	27.28	44.88	49.83	52.14	35.64	0	17.82	159.65	179.45	203.1	198.15
Day 29	10.12	2.64	1.43	8.47	0	0	0	169.77	182.09	204.53	206.62

Total CO2 produced in the inoculum blank during the test = 130.75 mg/3L = 43.58 mg/L

Note: Flask 1 and 2: Contain test item (methyl eugenol) and inoculum in mineral media

Flask 3 and 4: Contain inoculum in mineral media

Flask 5: Contain reference item (sodium benzoate) and inoculum in mineral media

Flask 6: Contain test item, reference item and inoculum in mineral media

Table 2: ph of Test Solutions

Flask No.	pH at the end of the test (Day 28)
Flask 1	7.83
Flask 2	7.8
Flask 3	7.82
Flask 4	7.79
Flask 5	7.82
Flask 6	7.84

Note: Flask 1 and 2: Contain test item (methyl eugenol) and inoculum in mineral media

Flask 3 and 4: Contain inoculum in mineral media

Flask 5: Contain reference item (sodium benzoate) and inoculum in mineral media

Flask 6: Contain test item, reference item and inoculum in mineral media

Table 3: Degradation of test item and refernce item

Day	Test item			Reference item	Test item + Refernce item
	Flask 1	Flask 2	Mean
Day 2	5.03	5.49	5.26	8.73	5.85
Day 4	7.44	9.53	8.49	18.86	12.09
Day 7	16.03	20.66	18.35	36.55	23.76
Day 9	25.85	30.1	27.98	54.91	36.87
Day 12	38.91	44.01	41.46	69.47	49.49
Day 15	50.99	53.67	52.33	79.79	67.5
Day 17	53.74	57.78	55.76	89.71	79
Day 21	65.42	66.93	66.18	98.38	86.89
Day 25	89.16	90.46	89.81	102.91	97.9
Day 29	94.77	106.53	100.65	122.16	118.4
Day 29	100.78	108.1	104.44	123.02	123.46

% degradation = (mg CO2 produced / (mg TOC added in test x 3.67)) x 100

Note: Flask 1 and 2: Contain test item (methyl eugenol) and inoculum in mineral media

Flask 3 and 4: Contain inoculum in mineral media

Flask 5: Contain reference item (sodium benzoate) and inoculum in mineral media

Flask 6: Contain test item, reference item and inoculum in mineral media

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Based on the results, it was concluded that the test item is bidoegradable as 104.44% mean degradation was achieved at the end of the test. Since, the test item degradation reached less than 60% pass level in 10 day window period after reaching 10& of ThCO2 production, the test item is not considered to be readily biodegradable.

Executive summary:

The ready biodegradability of 2,5 -di tertiary butyl 1,4 -benzoquinone (Yapox 2255) was tested using the CO2 Evolution Test. The test item was added to two vessels at the concentration of 60 mg/L of mineral medium (equivalent to 15.3 mg of Total Organic Carbon/L). Two control treatments containing only the medium only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each vessel. The residual barium hydroxide was measured on Days 2, 4, 7, 9, 12, 15, 17, 21, 25 and 29 after the initiation of the test.

The mean per cent degradation of test item was 104.44% at the end of the test while, the percent degradation of reference item was 123.02% and the toxicity control was 123.46% at the end of the test. It was observed that the mean degradation of test item reached 18.35% on Day 7 and further reached 55.76% on Day 17; and 66.18% on Day 21. Therefore, the degradation of test itme, 2,5 -di tertiary butyl 1,4 -benzoquinone (YAPOX 2255) reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production and within the 28 -d period of the test.

The test fulfilled the validity criteria.

Based on the results, it was concluded that the test item is biodegradable as 104.44% mean degradation was achieved at the end of test. Since, the test item degradation reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production, the test item is not considered to be readily biodegradable.

Description of key information

The ready biodegradability of 2,5 -di tertiary butyl 1,4 -benzoquinone (Yapox 2255) was tested using the CO2 Evolution Test. The test item was added to two vessels at the concentration of 60 mg/L of mineral medium (equivalent to 15.3 mg of Total Organic Carbon/L). Two control treatments containing only the medium only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each vessel. The residual barium hydroxide was measured on Days 2, 4, 7, 9, 12, 15, 17, 21, 25 and 29 after the initiation of the test.

The mean per cent degradation of test item was 104.44% at the end of the test while, the percent degradation of reference item was 123.02% and the toxicity control was 123.46% at the end of the test. It was observed that the mean degradation of test item reached 18.35% on Day 7 and further reached 55.76% on Day 17; and 66.18% on Day 21. Therefore, the degradation of test itme, 2,5 -di tertiary butyl 1,4 -benzoquinone (YAPOX 2255) reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production and within the 28 -d period of the test.

The test fulfilled the validity criteria.

Based on the results, it was concluded that the test item is biodegradable as 104.44% mean degradation was achieved at the end of test. Since, the test item degradation reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production, the test item is not considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window

Type of water:

freshwater