2,2,3,3,4,4,5,5,6,6-decafluoro-6-trifluorovinyloxyhexanenitrile

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:

22nd June 2001 - 19th July 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,2,3,3,4,4,5,5,6,6-decafluoro-6-trifluorovinyloxyhexanenitrile

EC Number:

443-050-2

EC Name:

2,2,3,3,4,4,5,5,6,6-decafluoro-6-trifluorovinyloxyhexanenitrile

Cas Number:

120903-40-4

Molecular formula:

C8F13NO

IUPAC Name:

2,2,3,3,4,4,5,5,6,6-decafluoro-6-[(1,2,2-trifluoroethenyl)oxy]hexanenitrile

Specific details on test material used for the study:

- Name of test material (as cited in study report): Perfluorohexane nitrile vinyl ether
- Lot/batch No.: Lot No. 3
- Expiration: 30th June, 2002
- Substance type: Pure active substance
- Physical state: clear colorless liquid
- Analytical purity: 93.8 Fl. % (GC)
- Storage condition of test material: In steel container, under inert gas (N2) at 2-8°C in refrigerator.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Domestic sewage purification treatment plant, Frankfurt am Main-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. Storage length and conditions were not specified.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

250 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 (22± 1°C), 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 test medium to 250 mL total volume
- Abiotic sterile control: single flask. 100 mg 3,5-dichlorophenol (as biocide), 62.5 mg test substance, activated sludge plus test medium to 250 mL total volume.
- Toxicity control: 24.3 mg test substance, activated sludge, test medium to 97 mL total volume.
- Procedural control: 15 mg aniline, activated sludge, test medium to 250 mL total volume.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

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 bottles 1 and 2 on days 1-3 (see Table 2).

BOD5 / COD results

Results with reference substance:

Reference substance aniline was 67% degraded by day 7 and 94% 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 1¹	Test bottle 2¹	Blank bottle 1	Blank bottle 2	Reference bottle²	Abiotic control¹	Toxicity control³
1	1.4	0	4.2	1.4	0	0	5.6
2	4.2	4.2	8.5	4.2	0	0	11.3
3	7.0	4.2	9.9	7.0	1.4	0	5.6
4	9.9	5.6	9.9	8.5	8.5	0	28.2
5	8.5	8.5	12.7	9.9	83.1	0	95.8
6	12.7	8.5	14.1	11.3	91.6	0	101
7	14.1	9.9	15.5	12.7	110	0	113
8	12.7	11.3	16.9	14.1	120	0	130
9	14.1	12.7	18.3	15.5	125	0	135
10	16.9	14.1	16.9	14.1	128	0	130
11	15.5	12.7	19.7	16.9	132	0	141
12	15.5	15.5	19.7	16.9	135	1.4	146
13	18.3	15.5	19.7	16.9	137	0	146
14	16.9	15.5	21.1	18.3	139	1.4	146
15	18.3	15.5	21.1	16.9	141	1.4	152
18	19.7	18.3	22.5	18.3	144	1.4	152
19	18.3	18.3	22.5	18.3	145	1.4	158
20	18.3	18.3	24.0	19.7	147	1.4	158
21	18.3	18.3	24.0	19.7	147	1.4	158
22	21.1	18.3	24.0	18.3	147	1.4	152
25	21.1	19.7	22.5	18.3	149	1.4	152
26	19.7	19.7	25.4	19.7	154	2.8	163
27	21.1	19.7	25.4	19.7	155	2.8	158
28	21.1	22.5	22.5	18.3	156	0	152

1. Perfluorohexane nitrile vinyl ether at 250 mg/L (ThOD[ammonium], 145 mg/L). Abiotic control was additionally treated with 250 mg/L 3,5 dichlorophenol as biocid

2, Reference substance aniline at 60 mg/L (ThOD[ammonium], 144 mg/L)

3, Toxicity control contained Perfluorohexane nitrile vinyl ether at 250 mg/L and aniline at 60 mg/L, ThOD [ammonium], 289 mg/L total

Table 2. Biodegradation (% BOD/ThOD)

Time	Test substance bottle 1	Test substance bottle 2	Reference substance	Toxicity control
1	-1	-2	-2	1
2	-2	-2	-4	-2
3	-1	-3	-5	-1
4	0	-2	0	7
5	-2	-2	50	29
6	0	-3	55	31
7	0	-3	67	34
8	-2	-3	73	40
9	-2	-3	75	41
10	1	-1	78	40
11	-2	-4	79	43
12	-2	-2	81	44
13	0	-2	83	44
14	-2	-3	83	44
15	0	-2	85	46
18	0	-1	86	46
19	-1	-1	87	48
20	-2	-2	87	47
21	-2	-2	87	47
22	0	-2	88	45
25	0	0	90	46
26	-2	-2	91	48
27	-1	-2	92	47
28	0	1	94	46

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Validity criteria: Difference in test sub biodeg <20%, ref sub passed by day 14 (67% degraded by 7d), >35% biodeg in tox control (46% degraded by 28d), O2 demand in blank 20-30 mg/L (18.3 and 22.5 mg/L).

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

MV5CN is not readily biodegradable (OECD 301 F), and does not inhibit biodegradation.

Executive summary:

Biodegradability of MV5CN was assessed in a OECD301F assay. Aniline was used as reference substance and in a toxicity control. The reference bottle achieved a passing level (67% BOD/ThOD[ammonium]) by day 7. No biodegradation was observed in duplicate test substance bottles. In the toxicity control, total oxygen demand was 46% after 28 days as compared to 92% oxygen demand in the reference substance bottle. MV5CN 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.