Benzoic acid, 2-fluoro-5-(methylsulfonyl)-

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:

May 2012 - August 2012

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Due to a misinterpretation about 50 mg/l test item and about 30 mg/l reference substance were tested in the toxicity control as a mixture and not about 50 mg/l test item and about 60 mg/l reference substance as described in the study plan. No influence.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-fluoro-5-methanesulfonylbenzoic acid

EC Number:

689-137-0

Cas Number:

247569-56-8

Molecular formula:

C8 H7 F O4 S

IUPAC Name:

2-fluoro-5-methanesulfonylbenzoic acid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

BMG sample no. M1204-02810-01

Physical form Solid

Batch no BS11020465

Purity 99.5%, treated as 100% pure

CAS no. 247569-56-8

Theoretical oxygen demand 1.320 mg O2/mg (calculated according to chapter 5.2)

Test substance storage At room temperature

Stability Stable under storage conditions

Expiry date 21 May 2013


Test substance 75.8 mg/l (100 mg ThOD/l)

Reference substance 60.0 mg/l (97.4 mg ThOD/l)

Toxicity control 75.0 mg/l of the test substance and 30.0 mg/l of reference substance (149 mg ThOD/l)

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Duration of test (contact time):

ca. 28

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Sampling time:

28 d

Remarks on result:

other: No significant biodegradability of test substance based on O2 consumption was observed during 28 days as compared to the theoretical oxygen demand.

Details on results:

Determination of biodegradation

Based on the data of the individual O2 determinations (Table 2, Figure 1), no significant
biodegradability in the Manometric Respirometry Test of 5-Methylsulfonyl-
2-fluorobenzoic acid RO4638493 was observed after 28 days (Figure 1).

The positive control, sodium benzoate, reached 90% biodegradation after 14 days, thus confirming
suitability of inoculum and test conditions (Table 3, Figure 2).

The respective DOC concentrations at the beginning and at the end of the test after
28 days were (in mg/l):

33.4 (1) and 41.5 for the test units (mean of two replicates)
<0.5 and 5.34 for the inoculum blank (mean of two replicates)
68.5 (1) and 7.51 for the procedure control (mean of two replicates)

(1) theoretical concentration based on molecular formula

The calculated biodegradation based on the DOC measurements confirmed the results based on the ThOD with no significant biodegradability for 5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 and 97% for sodium benzoate, respectively.

5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 is not biodegradable in the Manometric Respirometry Test.


Additional controls

At the applied initial test concentration of 75.0 mg/l the test substance showed no significant toxic effect on the microbial population, since the biodegradation of the mixture (test substance + reference compound sodium benzoate) was within the expected theoretical value during the whole test period (Table 3, Figure 2). The test was considered valid, since more than 25% degradation occurred within 14 days.

5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 was not abiotically degraded (by processes using O2) during the whole test period of 28 days in the asence of microorganisms as confirmed by the lack of oxygen consumption (Table 3).

Further remarks

At the end of the test the pH value of both inoculum blanks and the procedure control was 7.3 and 7.5, respectively. The pH values of the test units and both controls were 7.3, 7.5 and 7.2, respectively.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 is not biodegradable in the Manometric Respirometry Test.

Executive summary:

The biodegradability of 5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions.

No significant biodegradability of 5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 based on O₂ consumption was observed during 28 days as compared to the theoretical oxygen demand (ThOD).

The procedure control sodium benzoate reached 90% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

The calculated biodegradation based on the DOC measurements confirmed the results based on the ThOD with no significant biodegradability for 5-Methylsulfonyl- 2-fluorobenzoic acid RO4638493 and 97% for sodium benzoate, respectively.

5-Methylsulfonyl-2-fluorobenzoic acid RO4638493 is not biodegradable in the Manometric Respirometry Test.