4-bromo-3,3,4,4-tetrafluorobut-1-ene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 October 2020 to 22 March 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-bromo-3,3,4,4-tetrafluorobut-1-ene

EC Number:

242-440-8

EC Name:

4-bromo-3,3,4,4-tetrafluorobut-1-ene

Cas Number:

18599-22-9

Molecular formula:

C4H3BrF4

IUPAC Name:

4-bromo-3,3,4,4-tetrafluorobut-1-ene

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): collected from the Easton Wastewater Treatment Facility which treats predominantly residential wastes.
- Preparation of inoculum for exposure: The sludge was sieved and then aerated at test temperature until use.
- Concentration of sludge: After sieving, adjusted to approximately 1000 mg total suspended solids/L with mineral media.
- Type and size of filter used, if any: 2mm screen

A total suspended solids measurement and standard plate count were performed on the inoculum on the day of use in the test.

Plates were incubated at 22 ± 2 ºC for approximately 48 hours

Duration of test (contact time):

29 d

Initial test substance concentration

Initial conc.:

10 other: mg C/L

Based on:

test mat.

Remarks:

0.1293 g (%C calculated as 23.21%) added to test chamber with final volume 3000 mL

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Prepared by adding, per litre of high quality water: 1 mL calcium chloride solution (2.75%), 1 mL of ferric chloride solution (0.025%), 1 mL of magnesium sulphate solution (2.25%) and 10 mL of phosphate buffer solution (pH 7.4)
- Test temperature: 20-22ºC, with the average test temperature as 21 ºC.
- pH: 7.50
- pH adjusted: No
- Aeration of dilution water: No
- Suspended solids concentration: ≤30 mg/L



TEST SYSTEM
- Number of culture flasks/concentration: three replicates
- Method used to create aerobic conditions: bubbling CO2-free air through sludge
- Measuring equipment: Shimadzu Model TOC-VCSH carbon analyzer.
- Details of trap for CO2 and volatile organics if used: Three traps, containing KOH solution to convert CO2 to K2CO3.


SAMPLING
- Sampling frequency: days 3, 6, 9, 12, 15, 20, 25 and 29
- Sampling method: the CO2 trap nearest the test chamber was collected for analysis of inorganic carbon. The two remaining traps were placed one position closer to the test chamber and a new trap was placed on the end of the series.


CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: No
- Toxicity control: Sodium benzoate/test material (10/10 mg C/L)
- Other: Sodium benzoate (10 mg C/L)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

< 0

St. dev.:

1.2

Sampling time:

29 d

Details on results:

The actual result at day 29 varied between -0.6 to -2.9% for the three replicates. The Cumulative average at day 29 was -1.6% degradation. The highest % degradation value observed at any sampling point during the study, was 3.1% at day 9 but the other two replicates taken on same day were both negative percentages.

BOD5 / COD results

Results with reference substance:

An average percent biodegradation of greater than 60% was achieved by Day 6, thereby fulfilling the criteria for a valid test by reaching the pass level by Day 14.

Any other information on results incl. tables

Table 1 Dissolved Organic Carbon (DOC) and pH of test solutions at test termination

Test Chamber (Nominal concentration)	DOC (mg C/L)	pH
Control Rep. 1	2.0	7.46
Control Rep. 2	1.3	7.48
Control Rep. 3	1.2	7.47
Sodium Benzoate Rep. 1 (10 mg C/L)	1.4	7.55
Sodium Benzoate Rep. 2 (10 mg C/L)	1.5	7.57
Sodium Benzoate Rep. 3 (10 mg C/L)	1.4	7.56
Test material Rep. 1 (10 mg C/L)	8.1	7.50
Test material Rep. 1 (10 mg C/L)	7.5	7.50
Test material Rep. 1 (10 mg C/L)	7.3	7.50
Toxicity control (sodium benzoate/test item (10/10 mg C/L)	7.8	7.61

 

Table 2 Measured inorganic carbon concentration of trapping solutions (mg C/L)

		Blank	Blank	Blank	Sodium	Sodium	Sodium				Toxicity Control
Date	Day	Control	Control	Control	Benzoate	Benzoate	Benzoate	BTFB	BTFB	BTFB	BTFB/	KOH
		Rep. 1	Rep. 2	Rep. 3	Rep. 1	Rep. 2	Rep. 3	Rep. 1	Rep. 2	Rep. 3	Sodium Benzoate	Blank
1-Nov-20	3	38.5	36.0	37.8	179.0	187.8	202.1	35.0	36.6	36.5	96.6	8.2
4-Nov-20	6	39.5	42.3	44.1	130.5	112.3	104.8	35.4	38.9	51.1	150.3	6.9
7-Nov-20	9	39.6	39.2	37.4	64.0	57.3	62.2	38.2	35.5	39.7	85.8	7.3
10-Nov-20	12	29.6	32.8	30.6	41.4	42.4	44.6	29.3	31.6	30.5	51.3	7.6
13-Nov-20	15	31.8	28.3	30.2	35.1	40.6	37.9	26.1	31.7	29.2	41.2	10.0
18-Nov-20	20	26.8	29.4	25.3	27.7	27.2	29.5	35.8	33.5	27.4	35.9	11.7
22-Nov-20	25	24.0	25.6	29.8	25.1	23.9	27.5	24.0	21.9	22.1	27.9	10.3
27-Nov-20	29	19.9	19.5	20.2	17.8	16.3	17.9	20.4	19.2	14.7	17.4	6.8

 

Table 3 Cumulative milligrams of carbon dioxide evolved^1,2

Date	Day	Blank	Blank	Blank	Sodium	Sodium	Sodium				Tox Control	KOH
		Control	Control	Control	Benzoate^3	Benzoate^3	Benzoate^3	BTFB^3	BTFB^3	BTFB^3	BTFB/	Blank
		Rep. 1	Rep. 2	Rep. 3	Rep.1	Rep.2	Rep.3	Rep. 1	Rep. 2	Rep. 3	Sodium Benzoate
1-Nov-20	3	14.1	13.2	13.9	52.0	55.2	60.4	-0.9	-0.3	-0.3	21.7	3.0
4-Nov-20	6	28.6	28.8	30.1	84.4	81.0	83.5	-3.3	-1.5	3.0	61.5	5.5
7-Nov-20	9	43.1	43.1	43.8	93.7	87.8	92.1	-3.5	-2.6	3.4	78.8	8.2
10-Nov-20	12	54.0	55.2	55.1	97.5	92.0	97.1	-4.1	-2.4	3.2	86.2	11.0
13-Nov-20	15	65.7	65.6	66.1	99.3	95.8	99.9	-5.6	-1.9	2.8	90.2	14.7
18-Nov-20	20	75.5	76.3	75.4	99.5	95.8	100.8	-2.4	0.4	2.9	93.4	19.0
22-Nov-20	25	84.3	85.7	86.4	99.0	94.9	101.2	-3.4	-1.2	1.3	94.0	22.7
27-Nov-20	29	91.6	92.9	93.8	98.3	93.6	100.4	-3.2	-1.5	-0.6	93.1	25.2

¹The results of the inorganic carbon analyses of the CO2 traps were converted to mg CO2 produced using the following equation: mg CO2 = cumulative result (mg C/L) × vol. of KOH (L) × 3.67 mg CO2/mg C.
²Calculations performed in Excel 2010 full precision mode. Manual calculations may differ.
³Corrected for the CO2 attributed to the inoculum and the KOH by subtracting the average amount of CO2 evolved by the controls.

 

Table 4 Cumulative Percent of theoretical carbon dioxide evolved

		Blank	Blank	Blank	Sodium	Sodium	Sodium				Toxicity Control
Date	Day	Control	Control	Control	Benzoate	Benzoate	Benzoate	BTFB	BTFB	BTFB	BTFB/
		1	2	3	Rep. 1	Rep. 2	Rep. 3	Rep. 1	Rep. 2	Rep. 3	Sodium Benzoate
1-Nov-20	3	NA	NA	NA	47.2	50.1	54.9	-0.8	-0.3	-0.3	9.9
4-Nov-20	6	NA	NA	NA	76.7	73.6	75.8	-3.0	-1.3	2.7	27.9
7-Nov-20	9	NA	NA	NA	85.1	79.7	83.7	-3.2	-2.4	3.1	35.8
10-Nov-20	12	NA	NA	NA	88.6	83.5	88.2	-3.8	-2.2	2.9	39.1
13-Nov-20	15	NA	NA	NA	90.2	87.0	90.8	-5.1	-1.7	2.6	41.0
18-Nov-20	20	NA	NA	NA	90.4	87.0	91.6	-2.2	0.4	2.6	42.4
22-Nov-20	25	NA	NA	NA	89.9	86.2	91.9	-3.1	-1.1	1.2	42.7
27-Nov-20	29	NA	NA	NA	89.3	85.0	91.2	-2.9	-1.3	-0.6	42.3
Cumulative Average Day 29 (n=3)				88.5			-1.6		42.3
Standard Deviation				3.2			1.2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

In addition to valid result for positive control, also the toxicity control (containing both BTFB and sodium benzoate) achieved > 25% degradation by Day 14 and therefore BTFB may be considered non-inhibitory at the concentration tested in this study

Interpretation of results:

not readily biodegradable

Conclusions:

The final mean percent biodegradation for BTFB was -1.6% at the end of the test. Evidence of ready biodegradability in a Carbon Dioxide Evolution Test is 60% TCO2 within the 28-day test period.

The negative values for the test substance degradation could happen due to the slight variability between replicates for the test substance and the inoculum controls. A negative result in a test of ready biodegradability does not necessarily mean that the test substance will not be biodegradable under relevant environmental conditions, but that additional testing maybe needed.

The toxicity control achieved > 25% degradation by Day 14 and therefore BTFB may be considered non-inhibitory at the concentration tested in this study.