Tetraethylammonium tetrafluoroborate

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:

8 October - 23 October 2018

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:

OECD Guideline 301F, Section 3. Degradation and Accumulation. "Ready Biodegradability: Manometric Respirometry Test" (adopted July 17, 1992).

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

tetraethylammonium tetrafluoroborate

Cas Number:

429-06-1

Molecular formula:

C8H20BF4N

IUPAC Name:

tetraethylammonium tetrafluoroborate

Test material form:

solid: crystalline

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge: The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Storage conditions: The freshly obtained sludge was kept under continuous aeration until further treatment. Before use, the sludge was coarsely sieved (1 mm) and washed with mineral medium.
- Concentration: After treatment, the concentration of suspended solids (SS) was determined to be 3 g/L in the concentrated sludge as used for the test. The sludge was used as inoculum at a concentration of 2 mL per litre of mineral medium, leading to a final concentration SS of 6 mg/L.
- Preparation of inoculum for exposure: At the start of the test (day 0) mineral medium was inoculated with activated sludge.
At the start of the test (day 0), test and/or reference item were added to the respective bottles. The volumes of suspensions were made up to 360 mL or 244 mL using inoculated mineral medium. Rubber gaskets containing two pellets of sodium hydroxide were inserted into each bottle. Subsequently, each bottle was sealed by screwing an automated respirometer head on top.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

39 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: see materials and methods section
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 22-23 °C
- pH: The pH measured in all flasks at the start of the test was 7.7. At the end of exposure (Day 28), pH values in the range of 7.7 to 8.5 were measured.
- Suspended solids concentration: the concentration of suspended solids was determined to be 3 g/L in the concentrated sludge as used for the test.

TEST SYSTEM
- Test vessels: 500 mL brown colored glass bottles. The end volume of medium was 360 mL or 244 mL, in order to obtain the required headspace-to-volume ratio.
- Milli-RO water: Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon.
- Stock solutions of mineral components:       
A) 8.50 g KH2PO4
     21.75 g K2HPO4
     67.20 g Na2HPO4.12H2O
    0.50 g NH4Cl
     dissolved in Milli-RO water and made up to 1 litre, pH 7.4 ± 0.2
B) 22.50 g MgSO4.7H2O dissolved in Milli-RO water and made up to 1 litre.
C) 36.40 g CaCl2.2H2O dissolved in Milli-RO water and made up to 1 litre.
D) 0.25 g FeCl3.6H2O dissolved in Milli-RO water and made up to 1 litre.
- Mineral medium: 1 litre mineral medium contains: 10 mL of solution (A), 1 mL of solutions (B) to (D) and Milli-RO water.
- CO2 absorber: Sodium hydroxide pellets (Merck, Darmstadt, Germany).
- Illumination: The test media were excluded from light.
- Respirometer: Lovibond BD600-GLP manometric respirometry system, equipped with an inductive stirring system.

Reference substance

Reference substance:

other: Sodium acetate

Results and discussion

Preliminary study:

NDA

Test performance:

The ThOD of Tetraethylammonium tetrafluoroborate was calculated to be 2.10 mg O2/mg.
The ThOD of sodium acetate was calculated to be 0.78 mg O2/mg.
The relative biodegradation values calculated from the measurements performed during the test period based on ThOD, respectively 1% for bottle A and 2% for bottle B.
In the toxicity control, more than 25% biodegradation occurred within 14 days (54%, based on ThOD).
Functioning of the test system was checked by testing the reference item sodium acetate.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

1 - <= 2

Sampling time:

28 d

Details on results:

The relative biodegradation values calculated from the measurements performed during the test period based on ThOD, respectively 1% for bottle A and 2% for bottle B.

BOD5 / COD results

BOD5 / COD

Parameter:

ThOD

Value:

2.1 other: mg O2/mg

Results with reference substance:

The ThOD of sodium acetate was calculated to be 0.78 mg O2/mg.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Tetraethylammonium tetrafluoroborate was not readily biodegradable under the conditions of the Manometric Respirometry Test presently performed.

Executive summary:

The objective of the study was to evaluate the test item Tetraethylammonium tetrafluoroborate for its ready biodegradability in an aerobic aqueous medium with microbial activity introduced by inoculation with activated sludge; Manometric Respirometry Test.

Test duration was 28 days.

The relative biodegradation values calculated from the measurements performed during the test period revealed no biologically relevant biodegradation of Tetraethylammonium tetrafluoroborate, based on ThOD (1% and 2% for bottle A and B, respectively).

In the toxicity control, Tetraethylammonium tetrafluoroborate was found not to inhibit microbial activity.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

In conclusion, Tetraethylammonium tetrafluoroborate was designated as not readily biodegradable.