Sodium methanesulphonate

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:

September 19 to October 26, 1995

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

None.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

The inoculum came from the activated sludge of biological wastewater treatment plant from Abidos (France-64). The effluent, obtained 2 days before seeding the flasks, was centrifuged at approximately 20°C for 20 minutes at 4000 g; the base was resuspended in dilution water in order to keep the concentration unchanged with respect to the sample. The inoculum was preconditioned (aeration) until the flasks were inoculated. The percentage of dry material in the inoculum, determined by desiccation at 105°C until a constant weight is obtained, is 5.62 g/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Eight flasks were prepared: two inoculum controls for basal oxygen consumption monitoring, two inoculum+test substance, two inoculum+reference substance (sodium benzoate) controls and two toxicity controls (inoculum+test substance+reference substance). The flasks were plugged and installed in the respirometer where the stirring system was started. After a waiting period of 30 min, which was necessary to reach the thermal equilibrium of the solutions at 22°C, the aerated inoculum was added to all flasks, so that final inoculum concentration was 29.9 mg/L suspended solid. The flasks were incubated for 28 days.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

None.

Test performance:

Sodium benzoate reached 86% biodegradation (i.e. more than the 60% validity criterion) within 14 days and the toxicity control reached 92% within 14 days (i.e. more than the 25% criterion below which it is considered that the test substance is toxic to the inoculum).

Key result

Parameter:

% degradation (O2 consumption)

Value:

90

Sampling time:

28 d

Details on results:

The maximum biodegradation level of methanesulfonate acid was 90% after 28 days. 11 days were needed to reach 10% biodegradation and 84% biodegradation were observed within 10 further days. Therefore, the test substance was biodegraded by more than 60% during this ten-day window and by more than 70% at the end of the test. The substance is considered readily biodegradable.

Results with reference substance:

Sodium benzoate reached 86% biodegradation within 14 days (i.e. more than the 60% after 28 days validity criterion set out in the OECD 301F guideline) .

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Methane sulfonate is readily biodegradable.

Executive summary:

The purpose of this study was to assess the ready biodegradability of the test item according to the OECD 301F guideline. According to this guideline, the pass level for ready biodegradability is 60% of ThOD. The level has to be reached in a 10 -day window which begin after biodegradation of the test item has reached 10%. The pass level must be observed within the 28 -day period of the study. Under the test conditions, ultimate biodegradation of methanesulfonate was 90% after 28 days. At the end of the 10 -day window, ultimate biodegradation was 84%. All validity criteria set out in the OECD 301F guideline were fulfilled. Therefore, the study showed that methanesulfonate must be considered readily biodegradable.

Description of key information

A read-across was done for sodium methanesulphonate from methanesulphonic acid (see read-across justification).

The purpose of this study was to assess the ready biodegradability of the test item according to the OECD 301F guideline. According to this guideline, the pass level for ready biodegradability is 60% of ThOD. The level has to be reached in a 10 -day window which begin after biodegradation of the test item has reached 10%. The pass level must be observed within the 28 -day period of the study. Under the test conditions, ultimate biodegradation of methanesulfonate was 90% after 28 days. At the end of the 10 -day window, ultimate biodegradation was 84%. All validity criteria set out in the OECD 301F guideline were fulfilled. Therefore, the study showed that methanesulfonate must be considered readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable