Potassium 2-(3-trifluoromethoxy-1,1,2,2,3,3-hexafluoropropoxy)-2,3,3,3-tetrafluoropropionate

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:

18 Jan - 15 Feb 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

MV31-K-salt

IUPAC Name:

MV31-K-salt

Details on test material:

- Name of test material (as cited in study report): MV31 K-salt, Potassiumperfluoromethoxypropoxypropionate
- Substance type: Pure active substance
- Physical state: solid, grey granules
- Analytical purity: ca. 88 %
- Storage condition of test material: darkness at approximately 20 °C in a fume cupboard

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Domestic sewage treatment plant, Kriftel, Germany
- Preparation of inoculum for exposure: After a settling period of approximately 30 minutes the supematant liquid phase was decanted and crude particles were removed by a sieve. After resuspension with mineral medium, settling down and decantation, the sludge was concentrated by centrifugation. Before resuspension, an aliquot of concentrated sludge was used for dry weight determination. 10 g concentrated sludge was then resuspended in 1 liter of mineral medium.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

400 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: standard mineral medium per OECD 301 guidelines.
- Test temperature: 21.1 - 22.8 °C
- pH: 7.4 - 7.5
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 500-mL bottles in an incubation cabinet, continuous stirring by magnetic induction
- Test solutions: Bottles contained suspended solids at 30 mg/L final concentration, test or reference substance suspended in mineral medium, and mineral medium to the indicated final volume (normally 250 mL).
- Number of culture flasks/concentration: two
- Measuring equipment: test done using Oxitop ® system (WTW GmbH, Germany) to measure reduction in pressure in bottles due to oxygen consumption. Bottles closed throughout test.
- Details of trap for CO2 and volatile organics if used: system uses a potassium hydroxide trap in bottle lid to trap evolved carbon dioxide.

SAMPLING
- Sampling frequency: daily
- Sampling method: electronic manometer in bottle lid, pressure read and BOD determined after data transfer

CONTROL AND BLANK SYSTEM
- Inoculum blank: duplicate flasks. Activated sludge plus mineral medium to 250 mL total volume
- Abiotic sterile control: single flask. 100 mg 3,5-dichlorophenol (as biocide), 100 mg test substance, activated sludge to 250 mL total volume.
- Toxicity control: 38.8 mg test substance, activated sludge, to 97 mL total volume.
- Procedural control: 15 mg aniline, activated sludge, to 250 mL total volume.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Oxygen demand was less in test bottles than inoculum control throughout test except test bottle 2, day 15 (see Table 2). Total oxygen demand in the toxicity control was roughly equivalent to oxygen demand for the reference substance (see Table 1)

BOD5 / COD results

Results with reference substance:

Reference substance aniline was 72% degraded by day 10 and 96% degraded on day 28 (see Table 2)

Any other information on results incl. tables

Table 1, Cumulative biochemical oxygen demand by test bottle (mg/L)
Test day	Test bottle 1 ¹	Test bottle 2 ¹	Blank bottle 1	Blank bottle 2	Ref bottle ²	Abiotic control ¹	Toxicity control ³
1	1.4	2.8	5.6	2.8	0	0	0
4	4.2	8.5	11.3	9.9	60.6	0	56.3
5	4.2	9.9	11.3	11.3	88.8	0	113
6	5.6	11.3	11.3	11.3	95.8	0	141
7	7.0	12.7	16.9	14.1	100	0	152
8	8.5	12.7	16.9	15.5	103	0	158
10	9.9	14.1	16.9	15.5	120	0	169
11	9.9	15.5	18.3	16.9	125	0	169
12	9.9	15.5	16.9	15.5	132	0	169
13	9.9	15.5	18.3	16.9	137	0	175
14	11.3	16.9	18.3	16.9	138	0	180
15	11.3	16.9	15.5	16.9	139	0	180
18	8.5	16.9	19.7	19.7	147	0	180
19	9.9	18.3	19.7	19.7	148	0	186
20	9.9	19.7	22.5	19.7	151	0	192
21	9.9	19.7	22.5	19.7	152	0	192
22	9.9	19.7	22.5	21.1	154	1.4	192
25	11.3	21.1	24.0	21.1	156	2.8	197
26	11.3	21.1	21.1	21.1	158	1.4	197
27	11.3	21.1	24.0	22.5	159	2.8	197
28	11.3	22.5	24.0	21.1	161	2.8	197
1, MV31-K-salt at 400 mg/L (ThOD[ammonium], 147.2 mg/L). Abiotic control was additionally treated with 400 mg/L 3,5 dichlorophenol as biocide. 2, Reference substance aniline at 60 mg/L (ThOD[ammonium], 144 mg/L) 3, Toxicity control contained MV31-K-salt at 400 mg/L and aniline at 60 mg/L, ThOD [ammonium], 291.4 mg/L total.

Table 2, Biodegradation (% BOD/ThOD)
Test flask	Test substance bottle 1	Test substance bottle 2	Reference substance	Toxicity control
1	0	0	0	0
4	0	0	35	16
5	0	0	54	35
6	0	0	59	45
7	0	0	59	47
8	0	0	60	49
10	0	0	72	52
11	0	0	75	52
12	0	0	80	52
13	0	0	83	54
14	0	0	84	56
15	0	0.5	85	56
18	0	0	88	55
19	0	0	89	57
20	0	0	90	59
21	0	0	91	59
22	0	0	92	58
25	0	0	93	60
26	0	0	95	60
27	0	0	94	60
28	0	0	96	60

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

difference in test sub biodeg <20%, ref sub passed by day 14, >35% biodeg in tox control, O2 demand in blank 20-30 mg/L

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

MV31-K-salt is not readily biodegradable (OECD 301 F), but does not inhibit biodegradation.

Executive summary:

Biodegradability of MV31-K-salt was assessed in a OECD301F assay. Aniline was used as reference substance and in a toxicity control. The reference bottle achieved a passing level (60% BOD/ThOD[ammonium]) by day 8. No biodegradation was observed in duplicate test substance bottles. In the toxicity control, total oxygen demand was roughly equivalent to oxygen deman in the reference substance bottle. MV31-K-salt is not readily biodegradable, but does not inhibit biodegradation.

The test was conducted according to internationally accepted guidelines in accord with GLP criteria. It is considered reliable without restrictions and is acceptable for Risk Assessment, Classification & Labeling, and PBT Analysis.