Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

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:

1988-10-07-1988-11-08

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP guideline study. Deviations to the updated OECD Guideline (adopted 2010). The coefficient of analysis of the control was not reported.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted 1984

Deviations:

yes

Remarks:

See "Principles of method if other than guideline"

Principles of method if other than guideline:

Instead of a centrifuged sludge a settled sludge was used. The substance was tested at one concentration (100 mg/L) in duplicate samples.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test substance was added directly to the test vessel.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Activated sludge collected from the sewage treatment plant of CH - 4153 Reinach on 07/11/1988.
- The preparation was carried out according to the method described in the guideline. Except the settling instead of centrifuging.
- Initial biomass concentration: 1.8 g/L

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

Nominal and measured concentrations:

Nominal test concentrations: 102.5 and 107.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL BOD flasks with gas inlet
- Fill volume: 200 mL
- Aeration: none
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: 1.8 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated drinking water

TEST CONCENTRATIONS
- Test concentrations: 102.5 and 107 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

other: IC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

other: IC80

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none reported
- Effect concentrations exceeding solubility of substance in test medium: none reported

Results with reference substance (positive control):

- Results with reference substance valid? YES
- Relevant effect levels: IC50 = 9 mg/L

Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations. 

Additional information

In a 3-hr acute toxicity study sewage sludge micro-organisms were exposed to the test item at nominal concentrations of 100 mg/L in accordance with OECD 209. The IC50 value based on respiration rate after was > 100 mg/L after a 3 h contact time.