4-trans-Butyl-4'-trans-propyl-[1,1'-bicyclohexyl]

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jul 04 - Sep 17, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Version / remarks:

22 Oct 2010

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

[trans(trans)]- 4-Methyl-4'-propyl-1,1'-bicyclohexyl

EC Number:

816-312-2

Cas Number:

92343-70-9

Molecular formula:

C16H30

IUPAC Name:

[trans(trans)]- 4-Methyl-4'-propyl-1,1'-bicyclohexyl

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Appropriate amounts of test item were directly weight into the test vessels and test water was added. The composition was stirred intensively
- Controls: pure water, synthetic sewage and inoculum, but without addition of test item

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Test System: Activated sludge
Origin: Municipal sewage treatment plant of Darmstadt, Germany
Reason for the selection: Non-adapted activated sludge from the sewage plant at Bensheim is well suited as it receives predominantly municipal sewage and hardly any industrial chemical waste.
Pretreatment: The activated sludge used for this study was used as collected, but coarse particles were removed by settling for a short period (15 minutes) and then the upper layer decanted.
During holding prior to use the sludge was fed with 50 mL synthetic sewage feed (see below) per litre and kept aerated at room temperature overnight. An aliquot of the final sludge suspension was weighed, dried
and the ratio of wet sludge to its dry weight determined.
Based on the sludge dry matter, calculated amounts of wet sludge were suspended in pure water to yield a concentration equivalent to 3 g/L on dry weight basis. This level gives a concentration of 1.5 g/L suspended solids in the
test medium. The pH of the activated sludge inoculum was 6.9 and therefore no adjustment necessary.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20.4°C

pH:

control: 7.3 (start) to 8.6 (end)
test item: 7.3 (start) to 8.6 (end)

Dissolved oxygen:

Control samples : 6.9 mg O2/L

Nominal and measured concentrations:

test item: 100 mg/L (nominal)
positive control: 1, 4 and 16 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass flasks (approx. 1 litre) and Karlsruher flasks (250 mL)
- Type: open
- Aeration:compressed air (1.017 litre per minute)
- No. of vessels per test item concentration (replicates): 1
- No. of vessels per positive control concentration (replicates): 1
- No. of vessels of control (replicates): 2
- Sludge concentration (weight of dry solids per volume): 3.5 g/L
- Nutrients provided for bacteria: no
- Nitrification inhibitor used: N-allylthiourea

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



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
TEST CONCENTRATIONS
- Test item concentrations: 100 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Effect concentrations 2

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

At a nominal test concentration of 100 mg test item/L less than 10% inhibition was observed after three hours of
incubation. The mean deviation in respiration rate was 4.2% at three replicates of 100 mg Art. 201498.
The respiration rate of the activated sludge to the test material at the rate of 100 mg/L was not statistically significant reduced when compared to the control (Two
sample t-test procedure). The test material at the rate of 100 mg/L had no toxic effects on respiration activity of activated sludge.
Therefore it can be assumed that the NOEC is above 100 mg test item/L.

Results with reference substance (positive control):

3,5-Dichlorophenol
EC50 = 8.1 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

At a nominal test concentration of 100 mg test item/L less than 10% inhibition was observed after three hours of
incubation. The mean deviation in respiration rate was 4.2% at three replicates of 100 mg test material.
The respiration rate of the activated sludge to the test material at the rate of 100 mg/L was not statistically significant reduced when compared to the control (Two
sample t-test procedure). The test material at the rate of 100 mg/L had no toxic effects on respiration activity of activated sludge.
Therefore it can be assumed that the NOEC is above 100 mg test item/L.