Trimethylsulfonium bromide

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:

From 06 August to 10 September 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch No.: 20SP9-4
Appearance: White solid
Purity: 98.6%

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): A fresh sample of activated sludge was collected from the aeration tank of Shenyang North Sewage Treatment Plant two days before the test exposure was started.
- Preparation of inoculum for exposure: On the day of sludge collection, coarse particles were removed by filtration through a fine sieve and the sample was settled. After the supernatant was discarded, the sludge was washed twice with mineral medium and the concentrated sludge was suspended in mineral medium.
- Concentration of sludge: The suspended sludge was prepared with mineral medium to yield a concentration of 4.0 g/L as SS.

Duration of test (contact time):

28 d

Initial conc.:

62.8 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST SYSTEM
- Culturing apparatus: 250 mL flask
- Number of culture flasks/concentration: 2 replicates

CONTROL AND BLANK SYSTEM
- Inoculum blank: Test vessels containing only 250 mL inoculated mineral medium were prepared in duplicate and served as inoculum controls identified as IC-1 and IC-2.
- Toxicity control: Toxicity control test vessel contained both test item and reference item. Both, a weighed amount (0.0157 g) of test item and a weighed amount (0.0125 g) of reference item were added into test vessel. The concentration of test item was 62.8 mg/L (equivalent to 86.7 mg/L as ThODNH3) and the concentration of reference substance was 50.0 mg/L (equivalent to 83.5 mg/L as ThOD). The concentration expressed as total ThOD was 170.2 mg/L. One replicate (toxicity control identified as TC) was sufficient.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

78.1

Sampling time:

28 d

Details on results:

The average biodegradation of test item after 6 days and 1 hour was 10.7% (2 replicates), which was the initial time on which 10% biodegradation was exceeded, and when the 10-day window began. The average biodegradation were 74.9% within 10-day window (after 16 days and 2 hours), and 78.1% after 28 days.

Results with reference substance:

The biodegradation of the reference substance (Sodium benzoate) was 84.6% after 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The percentage biodegradation of Test item within 10-day window exceeded the pass level of 60% ThOD. The test item can be assumed to be readily biodegradable.

Executive summary:

The ready biodegradability test of Test item was conducted with unacclimatised sewage micro-organisms by measuring oxygen consumption over the 28-day test period, according to OECD Guideline 301F.

Based on the results, the percentage biodegradation of Test item within 10-day window exceeded the pass level of 60% ThOD. The test item can be assumed to be readily biodegradable under the described test conditions.

Description of key information

The ready biodegradability test of Test item was conducted with unacclimatised sewage micro-organisms by measuring oxygen consumption over the 28-day test period, according to OECD Guideline 301F.

Based on the results, the percentage biodegradation of Test item within 10-day window exceeded the pass level of 60% ThOD. The test item can be assumed to be readily biodegradable under the described test conditions.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater