[No public or meaningful name is available]

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

Study period:

1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

None

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

- Deion. water instead of dest. water for the stock solution. - Preparation of the inoculum : higher sludge weight after the washing procedure (Sludge concentrations in the test according to the guidelines) - 4 instead of 5 test concentrations

Principles of method if other than guideline:

Guideline followed

GLP compliance:

yes

Specific details on test material used for the study:

- Code number: FAT 20042/D
- Batch no. : 276
- Purity: ca 50%
- Solubility: insoluble
- Storage: room temperature
- Expiration date: 10/98

Analytical monitoring:

no

Details on sampling:

None

Vehicle:

not specified

Details on test solutions:

320, 100, 32 and 10 mg/l of the test substance
32, 10 and 3.2 mg/l of the reference substance

Test organisms (species):

activated sludge

Details on inoculum:

Organism: Activated sludge of a communal sewage treatment plant (ARA-Birsig Therwil)
Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage (a day before the main test)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

None

Post exposure observation period:

None

Hardness:

None

Test temperature:

21.0 °C

pH:

7.0 before the test beginning, after 3 h : 7.5 - 7.9

Dissolved oxygen:

None

Salinity:

None

Conductivity:

None

Nominal and measured concentrations:

320, 100, 32 and 10 mg/l of the test substance
32, 10 and 3.2 mg/l of the reference substance

Details on test conditions:

Sludge dry weight: 1.44 g/L
Test volume: 100 mL
Estimation technique: O2 - consumption, measured with an oxygen sensitive electrode system: OXI DIGI 530 (SAV : 00 109)
Aeration: 0.1 - 0.2 l/min by pasteur-pipette
pH of sludge: 7.0 before the test beginning

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Details on results:

The % inhibitions observed with 320, 100, 32 and 10 mg/L test concentrations were 3.27, 1.96, 4.58 and 12.42 % respectively.

Results with reference substance (positive control):

IC50 (3 h) of the reference substance 3,5-Dichlorophenol: 9.5 mg/l

Reported statistics and error estimates:

The respiration rate of each test concentration was calculated as a percentage of the mean of the two control respiration rates. The results were plotted on a logarithmic (concentration) / normal (% inhibition) graph, where the IC50 was evaluated.

None

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3 h) of the test substance FAT 20042/D was determined to be >320.0 mg/L

Executive summary:

The toxicity of FAT 20042/D to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test substance concentrations tested were 320, 100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l. The % inhibitions observed with 320, 100, 32 and 10 mg/L test concentrations were 3.27, 1.96, 4.58 and 12.42 % respectively. Based on the findings, the IC50 (3 h) of the test substance FAT 20042/D was determined to be >320.0 mg/l and the IC50 (3 h) of the reference substance 3,5-Dichlorophenol was 9.5 mg/l.

Description of key information

The IC50 of Acid Red 195 is greater than 320 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L

Additional information

The toxicity of FAT 20042/D to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test substance concentrations tested were 320, 100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l. The % inhibitions observed with 320, 100, 32 and 10 mg/L test concentrations were 3.27, 1.96, 4.58 and 12.42 % respectively. Based on the findings, the IC50 (3 h) of the test substance FAT 20042/D was determined to be >320.0 mg/l and the IC50 (3 h) of the reference substance 3,5-Dichlorophenol was 9.5 mg/l.

In other supporting studies that evaluated toxicity to microorganisms, the IC50 for Acid Red 195 was found to be >300 mg/l.