Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate

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:

From 2018-01-16 to 2018-12-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate from 25 September 2017

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate

EC Number:

911-467-3

Molecular formula:

C2O2F3K and CO2F3KS

IUPAC Name:

Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): a fresh sample of activated sludge was collected on Jan 16th, 2018 from the aeration tank of the Long Hua Wastewater Treatment Plant in Shanghai which treats predominantly domestic sewage with Anaerobic/Oxic (A/O) process. Sludge was kept under aeration until used.
- Preparation of inoculum for exposure: The sludge was washed with mineral medium. After centrifugation, the supernatant was decanted. This procedure was repeated three times (4000 rpm, 4°C, centrifuge 20 minutes). Then, 0.400 g of the concentrated sludge was weighed, dried at 105°C for 1 hour and then measured by moisture meter for 1 hour to determine the dry weight. According to the dry weight of 7.75%, 38.71 g of concentrated sludge was suspended in 1L mineral medium to yield a concentration of 3g dry matter/L. The final concentration of the activaged sludge in the test medium was 30 mg suspended solids/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

100 mg/L

Based on:

test mat.

Remarks:

Corresponding to 24.00 mg ThOD/L

Initial test substance concentration 2

Initial conc.:

210 mg/L

Based on:

test mat.

Remarks:

Corresponding to 50.40 mg ThOD/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral medium according to OECD 301
- Test temperature: 21.9 - 22.4°C
- pH: 7.05-7.83
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: BOD bottles (500 mL) with WTW Oxitop respirometer
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: the bottles were continuously stirred

TEST PROCEDURE
A stock solution of 500 mg test substance/L was prepared by dissolving 499.98 mg of the test substance in 1 L mineral medium. For the reference substance stock solution, 100.06 mg of sodium benzoate (Alfa Aesar, Lot SLBP6327V) was dissolved in 100 mL mineral medium to obtain a stock solution of 1 g/L. Blank control group (IB), procedure control group (PC), test substance group (TS) and toxicity control group (TC) were prepared as follows:
- Inoculum Blanks (IB1 & IB2): Inocolum (30 mg SS/L)
- Procedure Control: Reference substance (100 mg/L) + Inocolum (30 mg SS/L)
- Test Substance (TS1 & TS2): Test substance (210 mg/L, corresponding to ThOD of 50.40 mg/L) + Inoculum (30 mg SS/L)
- Test substance (TS3 & TS4): Test substance (100 mg/L, corresponding to ThOD of 24.00 mg/L) + Inocolum (30 mg SS/L)
- Inhbition Toxicity Control (TC1): Test substance (210 mg/L) + Reference substance (100 mg/L) + Inoculum (30 mg SS/L)
- Inhibition Toxicity Control (TC2): Test substance (100 mg/L) + Reference substance (100 mg/L) + Inoculum (30 mg SS/L)
The measuring flasks were placed on a stirring system for 28 days in the dark. The results of the oxygen measurements were auto-read once per 112 minutes during 28 days.

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

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

Validity criteria:
* Mean total O2 uptake in the inoculum blanks at the end of the test was less than 60 mg O2/L in 28 days
* reference substance was 90% by day 14
* different of extremes between replicates < 20%
* substance was not inhibitory to the inoculum
Based on these results it can be concluded that the validity criteria were met and that the test is considered valid.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

18

Sampling time:

22 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

22

Sampling time:

28 d

Details on results:

As the concentrations of the two test substance groups werre separated by a factor of around two, it was expected that the biological oxygen demand of these two groups would be separated by the same factor. However, results showed that under the experimental conditions, the biological oxygen demand in both test substance groups were around the same level at the end of the exposure period of 28 days. The toxicity control was negative, which demonstrates that the absence of difference of the biological oxygen demand was not due to the toxicity to the micro-organisms in the highest test substance group. Therefore, it is considered that the lowest tested concentration of test item was not sufficiently high to enable a correct determination of the percentage of degradation. Indeed, the concentration of ThOD in the lowest test substance group, i.e. 24 mg ThOD/L is outside the sensitivity of the method because it is far below the lowest recommended concentration in the OECD Guideline 301F, i.e. 50 mg ThOD/L.
The biodegradability of the test item is concluded on the results of the high test substance group (i.e. TS1-2). The biodegradation of the test substance attained an average of 18% at Day 22 (10-d window) and 22% at Day 28 which did not meet the 10-d window criteria of >60% ThOD removal.

BOD5 / COD results

Results with reference substance:

Toxicity control: The biodegradation percentage of the toxicity control (210.37 mg/L and 100 mg/L) was 65% and 74%, respectively by day 14, ≥ 25 ThOD, which met the guideline requirement of >25% biodegradation within 14 days.
Reference substance: The mean biodegradation of the reference substance (sodium benzoate) was 90% by Day 14, reaching the passlevel of the ready biodegradation test (>60% within 14 days).

Any other information on results incl. tables

Table 1: Biodegradation percentage of test substance group, procedure control and toxicity control (%)

Day (d)	Test Substance						Reference control			Toxicity control
	TS1	TS2	Average	TS3 (1)	TS4 (1)	Average	PC1	PC2	Average	TC1	TC2 (1)
1	-6	-6	-6	-7	-7	-7	12	12	12	-1	4
2	-5	-2	-4	-4	-4	-4	47	42	45	33	34
3	-1	-1	-1	-7	-7	-7	55	60	58	38	42
4	0	3	2	-6	-6	-6	64	67	66	44	52
5	2	0	1	-1	-1	-1	68	73	71	47	55
6	5	5	5	-1	-1	-1	78	78	78	53	62
7	8	8	8	0	0	0	81	83	82	57	65
8	9	7	8	2	2	2	80	82	81	58	66
9	9	9	9	8	2	5	80	84	82	59	66
10	9	9	9	8	8	8	82	86	84	60	67
11	6	9	8	7	7	7	85	89	87	63	70
12	8	11	10	16	16	16	88	88	88	64	71
13	9	12	11	18	30	24	90	89	90	64	74
14	10	13	12	27	33	30	90	90	90	65	74
15	12	14	13	36	36	36	91	90	91	66	75
16	13	13	13	40	40	40	92	91	92	67	76
17	14	14	14	41	41	41	95	93	94	68	77
18	14	17	16	41	41	41	95	93	94	68	77
19	11	19	15	41	41	41	96	94	95	70	79
20	15	23	19	49	43	46	95	95	95	72	80
21	17	22	20	53	47	50	97	97	97	72	82
22	18	18	18	50	44	47	97	96	97	71	82
23	18	18	18	50	44	47	97	94	96	71	82
24	18	18	18	50	44	47	96	96	96	71	81
25	17	20	19	48	42	45	97	95	96	72	82
26	21	21	21	55	49	52	97	94	96	71	82
27	20	26	23	54	48	51	95	94	95	72	82
28	19	25	33	53	47	50	97	95	96	72	82

(1)   Results of these columns are considered as not reliable because the concentration ThOD is too low (see explanations in "details on results").

(2)   Negative calculated values were regarded as zero

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

See in the field "Overall remarks".

Interpretation of results:

not readily biodegradable

Conclusions:

The biodegradation of the Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinateattained an average of 18% at Day 22 (10-d window) and 22% at Day 28. Therefore the test item is not considered to be readily biodegradable under the experimental conditions.

Executive summary:

The aerobic biodegradability of Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate was investigated in a GLP-compliant ready biodegradability study performed in accordance with OECD Guideline No. 301 F. The biodegradation was followed during 28 day, with an initial test substance concentration of 210 mg/L (corresponding to 50.4 mg ThOD/L) using a non-adapted inoculum. Dissolved oxygen consumption was measured continuously.

The mean total oxygen uptake in the inoculum blanks at the end of the test was < 60 mg O2/L. The biodegradation of the reference substance (sodium benzoate) reached the pass level of ready biodegradation test (>60% within 14 days). The degradation of the toxicity control after 14 days was >25%; the test item had no inhibitory effect on the inoculum according to the criterion of the guideline. Therefore the test is considered valid.

The biodegradation of the test item attained an average of 18% at Day 22 (10 -d window) and 22% at Day 28. Therefore the test item is not considered to be readily biodegradable under the experimental conditions.