2,2,3,3,8,8,9,9-octafluorotricyclo[8.2.2.2⁴,⁷]hexadeca-1(12),4,6,10,13,15-hexaene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

1

Reference substance name:

2,2,3,3,8,8,9,9-octafluorotricyclo[8.2.2.2⁴,⁷]hexadeca-1(12),4,6,10,13,15-hexaene

EC Number:

639-791-8

Cas Number:

3345-29-7

Molecular formula:

C16H8F8

IUPAC Name:

2,2,3,3,8,8,9,9-octafluorotricyclo[8.2.2.2⁴,⁷]hexadeca-1(12),4,6,10,13,15-hexaene

Specific details on test material used for the study:

Batch n. 340421
Production date November 19, 2021
Expiry date November 19, 2024
Purity ≥98.00%

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Remarks:

The study was performed using aerobic activated sludge from BRIANZACQUE civil wastewater treatment plant.

Details on inoculum:

A homogenized aliquot of the wet sludge was centrifuged, the supernatant was removed while the solid phase was weighed, dried and the ratio of wet to dry weight was calculated to be equal to 7.4%.
Based on this ratio, calculated amounts of wet sludge was centrifuged, the supernatant was removed and the solid phase was suspended in the test medium to get a concentration equivalent to 3 g dry material per litre.
The prepared sludge inoculum was pre-conditioned to the experimental conditions by aerating it in the dark. The concentrated suspension was used as inoculum to give a final concentration of 15 mg dry material per litre into test flasks.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

100 mg/L

Initial test substance concentration 2

Initial conc.:

81.8 mg/L

Based on:

ThOD

Details on study design:

The assay on test item was carried out in parallel with the following bottles:
- a known ready biodegradable reference item (one replicate), Sodium Benzoate, at 100 mg/L;
- two inoculum control replicates (blank);
- two test item replicates at 50.0 mg/L concentration.
- one abiotic control containing the test item at 50.0 mg/L and a sterilizing agent (HgCl2) at 100
mg/L (without inoculum);
- one toxicity control, containing the test item at 50.0 mg/L and reference item at 100 mg/L.

BOD flasks of 500 mL capacity, equipped with pressure sensors fitted on the bottle mouth, were used as test units.

The method is based on an electro-chemical analyses process. The iodegradation process consumes the dissolved oxygen in liquid and generates CO2. Evolved carbon dioxide is adsorbed by potassium hydroxide and the total pressure decreases in the test flasks.
The pressure decrease is detected and converted into an electrical signal by means of an electrode type manometer.

Test item concentration should be 100 mg/L or a concentration giving at least 50-100 ThOD /L.
The tested concentration was 50.0 mg/L (corresponding to 81.8 mg ThOD/L).
All reported results are related to the nominal concentration of test item, since the test concentrations were not measured during the test.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

18.9

Sampling time:

10 d

Remarks on result:

other: mean percentage values between two test item replicates

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

16.5

Sampling time:

28 d

Remarks on result:

other: mean percentage values between two test item replicates (22%), after nitrification correction.

BOD5 / COD results

Results with reference substance:

The reference item exceeded (85.6%) the biodegradation pass level (60%) within the range fixed by
OECD Guideline 301F (first 14 days).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

At the end of the 10-day window the biodegradation was 18.9% (mean percentage values between two replicates).
Therefore, the test item, was found to be not ready and completely biodegradable under the
conditions applied in a manometric respirometry test.
At the end of the test (28 day) and after nitrification correction, a maximum biodegradation of 16.5% was found, (mean percentage values between two replicates).

Executive summary:

A study to evaluate the ready biodegradability of the test item PARYLENE HT®:, following the “Manometric Respirometry” method, was performed.

Test item concentration should be 100 mg/L or a concentration giving at least 50-100 ThOD /L.
The tested concentration was 50.0 mg/L (corresponding to 81.8 mg ThOD/L).
All reported results are related to the nominal concentration of test item, since the test concentrations
were not measured during the test.

The biodegradation was followed by measuring the oxygen uptake (mg/L) of the test item under
defined conditions by the means of a manometric method and calculating from these values the BOD
(Biochemical Oxygen Demand).

The ThODNH3 value (Theoretical Oxygen Demand without nitrification process) was calculated to be
equal to 1.67 mg O2/mg for reference item, Sodium Benzoate, while ThODNH3 value was assessed to
be 1.64 mg O2/mg for the test item.

These values, 1.67 mg O2/mg for reference item and 1.64 mg O2/mg for the test item, were used to calculate per % biodegradation.

Nitrate and nitrite concentration were measured at the start and at the test end.
At the start and test end no nitrite and nitrate were present.

At the test end nitrate concentration in the blank bottles (4.00 mg/L as mean value) was subtracted from the nitrate concentration found in test item bottles (8.35 mg/L as mean value), therefore the found value (4.35 mg/L), calculated as Total oxygen equivalent, was subtracted from the test biodegradation value at the end of the test.

At the end of the 10-day window the biodegradation was 18.9% (mean percentage values between two replicates).
Therefore, the test item, was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test.
At the end of the test (28 day) and after nitrification correction, a maximum biodegradation of 16.5%
was found, (mean percentage values between two replicates).

No significant degradation was observed in the abiotic control (equal to 7.3% at the test end).
The toxicity control clearly showed that the test item does not cause inhibitory effect on the microorganisms activity at the tested concentration. The toxicity control exceeded the 25 % pass level within the 14 days of exposure (42.1%).

The reference item exceeded (85.6%) the biodegradation pass level (60%) within the range fixed by OECD Guideline 301F (first 14 days).