3-anilino-5-methyl-5-(4-phenoxyphenyl)-1,3-oxazolidine-2,4-dione;famoxadone (ISO)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Commission Directive 87/302/EEC: "Activated Sludge Respiration Inhibition Test", Official Journal of the European Communities No. L 133/118-122, dated May 30, 1988

Version / remarks:

1988

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Purity: 97.28%
DPX-JE874-221

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Two controls (tap water, synthetic sewage and inoculum, but without addition of the test substance) were tested in parallel

Details on test solutions:

Since the test substance is not soluble in water the test concentrations of nominal 10.0, 32.0 and 100.0 mg test substance/ L were prepared by weighing the test substance directly into each test flask. Due to the low amount of test substance needed at the nominal test substance concentrations of 1.0 and 3.2 mg/L a direct dosage of the test substance into the test flasks was not possible. Therefore, a stock suspension of nominal 100 mg test substance/L was prepared by dosing 10 mg test substance into 100 mL deionized water. The stock suspension was ultrasonically treated for 15 minutes and intensively stirred for 30 minutes to homogenize the test substance far as possible. Amounts of 16 and 5 mL stock suspension were taken from the intensively stirred suspension by pipette and were dosed into the test flasks to prepare the two lowest test concentrations.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture:
activated sludge, micro organisms from a domestic waste water treatment plant.
- Name and location of sewage treatment plant where inoculum was collected:
supplied by the sewage plant Groß-Zimmern, Germany
The sludge was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. The latter procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge (g) to its dry weight (g) determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3 g dry material per litre, were made up with tap water. To this mixture, 50 mL synthetic sewage feed per litre was added daily, starting two days prior to use, and the sludge was kept at room temperature under continuous aeration until use. Immediately before use, the dry weight of e activated sludge was determined, and adjusted to 3 g/L with tap water again. The pH of the activated sludge was determined to be pH 7.5.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

pH:

7.1 - 8.2

Nominal and measured concentrations:

Nominal: 0, 1.0, 3.2, 10.0, 32.0, and 100.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
glass flasks of approximately 1 litre volume and Karlsruher flasks of 250 mL volume
- Aeration:
with compressed air (approximately 0.6 litre per minute); air flow rate was determined manually
- No. of vessels per concentration (replicates):
1
- No. of vessels per control (replicates): 1

EFFECT PARAMETERS MEASURED :
For the measurement of the respiration rate a well mixed sample of each test medium was poured into a Karlsruher flask after exactly 3 hours incubation time, and was not further aerated. The oxygen concentration was measured with an oxygen electrode, and was recorded for about ten minutes. During measurement, the samples were continuously stirred on a magnetic stirrer. The oxygen consumption (in mg O2 L-1 minute-1) was determined from the most linear part of the respiration curve.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

other: inhibition of respiration rate

Details on results:

In comparison to the inoculum controls the respiration rate of the activated sludge was not or only slightly inhibited by -2.6 % to 7.7 % up to the highest tested concentration of nominal 100 mg test substance/L. From the determined inhibition rates, the 3-hour EC 20 and EC 50 could not be quantified because up to the highest nominal test concentration of 100 mg/L less than 20 % inhibition was noted after three hours contact time. Nevertheless, the 3-hour EC 20 and EC 50 are clearly higher than 100 mg/L nominal under the present test conditions.

For the reference substance, the 3-hour EC 50 was calculated to be 7.5 mg/L with the 95 % confidence limits from 6.8 to 8.3 mg/L.

Results with reference substance (positive control):

The 3-hour EC 50 for the positive control 3,5-dichlorophenol, which was tested in the same way as the test item, was found to be 7.5 mg/L and is within the range of 5-30 mg/L recommended by the test guidelines; thus, confirming suitability of the activated sludge.

EC50 for the test substance > 100 mg/L

Flask	Treatment	Concentration (mg/L)	Oxygen Consumption (mg O2/L min)	Inhibition (%)	pH		Oxygen concentration (mg O2/L)
					start	end	start	end
1	Control	-	0.380	-	7.1	8.1	8.0	7.6
10	Control	-	0.400	-	7.1	8.1	8.0	7.4
Mean			0.390
% deviation			5
5	Test item	100.0	0.368	5.6	7.5	8.2	7.9	7.9
6	Test item	32.0	0.360	7.7	7.4	8.2	8.1	8.0
7	Test item	10.0	0.390	0.0	7.2	8.2	8.1	7.4
8	Test item	3.2	0.400	-2.6	7.2	8.1	8.0	7.1
9	Test item	1.0	0.400	-2.6	7.1	8.0	8.0	7.4

Validity criteria fulfilled:

yes

Conclusions:

3-hr EC50 > 100 mg/L

Executive summary:

The influence of the test item Famoxadone Technical on the activity of activated sludge was evaluated by measuring the respiration rate under defined conditions. The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of various concentrations of the test item after an incubation period of 3 hours. Test concentrations: 100.0, 32.0, 10.0, 3.2 and 1.0 mg Famoxadone Technical/L; 32.0, 10.0 and 3.2 mg 3,5-dichlorophenol/L and two inoculum controls.

 

In comparison to the inoculum controls the respiration rate of the activated sludge was not or only slightly inhibited by -2.6% to 7.7% up to the highest nominal test concentration of 100 mg test substance/L. 

 

The 3-hour EC 50 for the positive control 3,5-dichlorophenol, which was tested in the same way as the test item, was found to be 7.5 mg/L and is within the range of 5 - 30 mg/L recommended by the test guidelines; thus, confirming suitability of the activated sludge.

 

The 3-hour EC 20 and EC50 of Famoxadone Technical was determined to be was higher than 100 mg test item/L.

Description of key information

3-hr EC50 (activated sludge)  > 100 mg/L, OECD 209 and Commission Directive 87/302/EEC: "Activated Sludge Respiration Inhibition Test", Official Journal of the European Communities No. L 133/118-122, dated May 30, 1988, Reliability = 1

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

The 3-hr EC50 value for Famoxadone when tested in activated sludge was > 100 mg/L.