Methylium, triphenyl-, tetrakis(pentafluorophenyl)borate(1-).

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 October - 2 November 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

December 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

17 July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): municipal sewage treatment plant 'Waterschap de Maaskant', 's-Hertogenbosch, The Netherlands
- Storage conditions: under continuous aeration
- Preparation of inoculum for exposure: before use, the sludge was allowed to settle (38 minutes) and the liquid was decanted for use as inoculum
- Concentration of sludge: 4.5 g suspended solids per litre of concentrated sludge
- Initial cell/biomass concentration: 10 ml/l of mineral medium

Duration of test (contact time):

28 d

Initial conc.:

87.9 - 89 other: mg CO2/2L

Based on:

ThCO2

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Test vessels: 2 litre all-glass brown coloured bottles
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-Q water and made up to 1 litre, pH 7.4
B) 22.50 g MgSO4.7H2O dissolved in Milli-Q water and made up to 1 litre
C) 36.40 g CaCl2.2H2O dissolved in Milli-Q water and made up to 1 litre
D) 0.25 g FeCl3.6H2O dissolved in Milli-Q water and made up to 1 litre
Mineral medium: 1 litre mineral medium contains: 10 ml of solution A, 1 ml of solutions B, C and D, and Milli-RO water.
Barium hydroxide: 0.0125 M Ba(OH)2 stored in a sealed vessel to prevent absorption of CO2 from the air.
Synthetic air (CO2 < 1 ppm): a mixture of oxygen (21%) and nitrogen (79%) was passed through a bottle containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was sparged through the scrubbing solutions at a rate of 1-2 bubbles per second (ca. 30-100 ml/min).
Pre-incubation medium: mineral components, Milli-RO water (ca. 80% total volume) and inoculum (1% final volume) were added to each bottle. This mixture was aerated with synthetic air overnight to purge the system of CO2.
Type and number of bottles: 2 test suspension bottles (test substance + inoculum), 2 inoculum blank bottles (only inoculum), 1 positive control bottle (reference substance + inoculum), 1 toxicity control bottle (test substance + reference substance + inoculum)
Preparation: the test substance and positive control were added to the bottles containing the microbial organisms and mineral components. The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before. Three CO2-absorbers were connected in series to the exit air line of each test bottle.

Reference substance:

acetic acid, sodium salt

Test performance:

All criteria for acceptability of the test were met, so the study was considered valid.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

2 - 3

Sampling time:

29 d

Details on results:

The relative degradation values calculated from the measurements performed during the test period revealed no significant degradation of the test substance.
In the toxicity control more than 25% degradation occurred within 14 days (34% based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.
Temperature ranged between 21.5 and 22.8°C, pH 7.1-7.5.

Results with reference substance:

The degradation of sodium acetate after 29 days was 72%.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The substance was not readily biodegradable under the conditions of the modified Sturm test.

Description of key information

The substance was not readily biodegradable under the conditions of the modified Sturm test. Furthermore, in the toxicity control, more than 25% degradation occurred within 14 days. Therefore the test substance was assumed not to inhibit microbial activity.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater