N-[4-(2',7'-ditert-butyl-9,9'-spirobi[fluorene]-2-yl)phenyl]-9,9-dimethyl-N-(2-phenylphenyl)fluoren-2-amine

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:

Oct 17, 2019 to Jan 06, 2020

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 (Carbon and Ammonium Oxidation))

Version / remarks:

July, 2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Based on the results of the preliminary test it was concluded that the heterotrophic respiration as well as the nitrification are not inhibited. Therefore, the definitive study was carried out with the concentration of 1000 mg/L in 3 replicates (limit test to determine the NOEC).

The test item was weighed out directly in Erlenmeyer flasks and stirred overnight in 200 mL ultrapure water. Triplicates of the control without test item were included at the beginning and at the end of the test.
The reference item was tested with three concentrations with the concentration range 58 - 180 mg/L and a dilution factor of approx. 1.8.

A fresh sample of activated sludge taken from the sewage plant Hildesheim was used for the test procedure. It was washed twice and adjusted with chlorine free tap water to a dry sludge
concentration of 3.0 g/L ± 10 %. The oxygen uptake rates of all samples were determined following an incubation period of 3 h.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Test System: Activated sludge
Origin: MMunicipal sewage treatment plant of 30982 Pattensen, Germany
Reason for the selection: Non-adapted activated sludge from the sewage plant at Hildesheim is well suited as it receives predominantly municipal sewage and hardly any industrial chemical waste.
Pretreatment: The sludge was washed twice with chlorine free tap water and adjusted to a dry sludge concentration of 3.0 g/L ± 10 %. The sludge was used within 24 h after sampling.
Date of receipt: 2019-10-29
Dry sludge concentration: 2.85 g/L ( corresponding to 1.43 g/L suspended solids in the test vessels)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

19.5°C

pH:

pH of activated sludge: 7.40
pH of synthetic waste water: 7.21

Dissolved oxygen:

Control samples : 7.19 - 8.37 mg/O2/L

Nominal and measured concentrations:

Range Finder: 10, 100 and 1000 mg/L
Main study: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL Erlenmeyer flasks, DIN 12380
- Type: open
- Aeration:compressed air supply
- No. of vessels per test item concentration (replicates): 5
- No. of vessels of positive control (replicates): 3
- No. of vessels of control (replicates): 6
- Sludge concentration (weight of dry solids per volume): 2.85 g/L
- Nutrients provided for bacteria: no
- Nitrification inhibitor used (delete if not applicable): N-allylthiourea (only one replicate of the dose range finding study)

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 1000 mg/L
- Results used to determine the conditions for the definitive study: range finding test

Reference substance (positive control):

yes

Remarks:

Copper (II) sulphate pentahydrate (CAS No. 7758-99-8)

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of heterotrophic respiration

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of heterotrophic respiration

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of heterotrophic respiration

Results with reference substance (positive control):

copper-(II)-sulphate pentahydrate
EC50 = 95.6 mg/L, 95% range: (84.8-107.0) mg/L

Validity criteria fulfilled:

yes

Conclusions:

The test item caused no inhibiting effects on activated sludge of a municipal sewage treatment plant. The EC50 value exceeded the limit concentration of 1000 mg/L.

Description of key information

The test item caused no inhibiting effects on activated sludge of a municipal sewage treatment plant. The EC50 and EC10 value exceeded the limit concentration of 1000 mg/L. The NOEC was determined to be 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L