Boron, (benzenemethanamine)trifluoro-, (T-4)-, reaction products with Bu glycidyl ether

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

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained on 12 December 2016 from the aeration stage of the Severn Trent Water Plc sewage treatment
plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

Preparation of Inoculum
The activated sewage sludge sample was washed twice by settlement and re-suspension in mineral medium to remove any excessive amounts of dissolved organic carbon (DOC) that
may have been present. The washed sample was then maintained on continuous aeration in the laboratory at a temperature of approximately 21 ºC and used on the day of collection.
Determination of the suspended solids level of the activated sewage sludge was carried out by filtering a sample (100 mL) of the washed activated sewage sludge by suction through
preweighed GF/A filter paper* using a Buchner funnel. Filtration was then continued for a further 3 minutes after rinsing the filter three successive times with 10 mL of deionized
reverse osmosis water. The filter paper was then dried in an oven at approximately 105 ºC for at least 1 hour and allowed to cool before weighing. This process was repeated until a
constant weight was attained. The suspended solids concentration was equal to 3.0 g/L prior
to use.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Preparation of Test System
The following test preparations were prepared and inoculated in 5 liter test culture vessels each containing 3 liters of solution:
a) An inoculated control, in duplicate, consisting of inoculated mineral medium.
b) The procedure control containing the reference item (sodium benzoate), in duplicate,
in inoculated mineral medium to give a final concentration of 10 mg carbon/L.
c) The test item, in duplicate, in inoculated mineral medium to give a final concentration
of 10 mg carbon/L.
d) The test item plus the reference item in inoculated mineral medium to give a final
concentration of 20 mg carbon/L to act as a toxicity control (one vessel only).
Data from the inoculum control and procedure control vessels was shared with similar concurrent studies. Each test vessel was inoculated with the prepared inoculum
at a final concentration of 30 mg suspended solids (ss)/L. The test was carried out in a temperature controlled room at temperatures of between 19 and 24 °C,
in darkness.
Approximately 24 hours prior to addition of the test and reference items the vessels were filled with 2400 mL of mineral medium and 30 mL of inoculum and aerated overnight.
On Day 0 the test and reference items were added and the pH of all vessels measured using a Hach HQ40d Flexi handheld meter. If necessary the pH was adjusted to pH 7.4 ± 0.2 using
diluted hydrochloric acid or sodium hydroxide solution prior to the volume in all the vessels being adjusted to 3 liters by the addition of mineral medium which had been purged
overnight with CO2 free air.
The test vessels were sealed and CO2-free air bubbled through the solution at a rate of 30 to 100 mL/min per vessel and stirred continuously by magnetic stirrer.
The CO2-free air was produced by passing compressed air through a glass column containing self-indicating soda lime (Carbosorb®) granules.
The CO2 produced by degradation was collected in two 500 mL Dreschel bottles containing 350 mL of 0.05 M NaOH. The CO2 absorbing solutions were prepared using purified water.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

Preliminary Investigational Work
The results obtained from the samples taken for DOC analysis from the preliminary investigational work indicated that the test item did not adsorb to filter matricesor to activated sewage sludge. Therefore, for the purpose of the study, the samples taken for DOC analysis were filtered to remove the suspended solids present without the loss of any test item.

Test performance:

Definitive Test
Percentage biodegradation values of the test and reference items and the toxicity control are given below.
Validation Criteria
The total CO2 evolution in the inoculum control vessels on Day 28 was 41.46 mg/L and therefore satisfied the validation criterion given in the OECD Test Guidelines. Although the
CO2 evolution was in excess of 40 mg/L at the end of the test, this was considered not to affect the integrity of the study given that the upper level of 70 mg CO2/L given in the OECD
Test Guidelines was not exceeded, and that all other validation criteria were satisfied.
The IC content of the test item suspension in the mineral medium at the start of the test (see Table 3) was below 5% of the TC content and hence satisfied the validation criterion
given in the OECD Test Guidelines.
The difference between the values for CO2 production at the end of the test for the replicate vessels was <20% and hence satisfied the validation criterion given in the OECD Test
Guidelines.
Biodegradation
The test item attained 76% biodegradation after 28 days and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the
biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.
The toxicity control attained 74% biodegradation after 10 days, 87% biodegradation after 15 days and 92% biodegradation after 28 days thereby confirming that the test item did not
exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test.
Sodium benzoate attained 82% biodegradation after 10 days, 77% biodegradation after 15 days and 88% biodegradation after 28 days thereby confirming the suitability of the
inoculum and test conditions. The slight decrease in biodegradation between Days 10 and 15 was considered to be due to sampling/analytical variation.

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

0 d

Parameter:

% degradation (CO2 evolution)

Value:

13

Sampling time:

2 d

Parameter:

% degradation (CO2 evolution)

Value:

53

Sampling time:

6 d

Parameter:

% degradation (CO2 evolution)

Value:

69

Sampling time:

8 d

Parameter:

% degradation (CO2 evolution)

Value:

69

Sampling time:

10 d

Parameter:

% degradation (CO2 evolution)

Value:

86

Sampling time:

15 d

Parameter:

% degradation (CO2 evolution)

Value:

84

Sampling time:

21 d

Parameter:

% degradation (CO2 evolution)

Value:

83

Sampling time:

28 d

Parameter:

% degradation (CO2 evolution)

Value:

76

Sampling time:

29 d

Remarks on result:

other:

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Boron, (benzenemethanamine)trifluoro-,(t-4)-, reaction products with bu glycidyl ether attained 76% biodegradation after 28 days and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Executive summary:

Boron, (benzenemethanamine)trifluoro-,(t-4)-, reaction products with bu glycidyl ether attained 76% biodegradation after 28 days and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Description of key information

Boron, (benzenemethanamine)trifluoro-,(t-4)-, reaction products with bu glycidyl ether attained 76% biodegradation after 28 days and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable