[2R-[2α(E),3β]]-2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethyl-3-hydroxycyclopentan-1-one

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD guideline under GLP

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Principles of method if other than guideline:

not relevant

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

[2R-[2α(E),3β]]-2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethyl-3-hydroxycyclopentan-1-one

EC Number:

257-409-4

EC Name:

[2R-[2α(E),3β]]-2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethyl-3-hydroxycyclopentan-1-one

Cas Number:

51773-49-0

Molecular formula:

C20H26O3

IUPAC Name:

17 beta-Hydroxy-3-methoxy-18-methyl-8,14-seco-1,3,5(10),9(11)-estratetraen-14-one

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): 13-Ethylsecol
- Analytical purity: 97.9%
- Lot/batch No.: 57130532

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Any other information on results incl. tables

The EC50 (respiration inhibition) values for 13 -Ethylsecol have been determined as > 10 mg/L for

the 30-minute exposure time and > 10 mg/L for the 3-hour exposure time (10 mg/L was the

highest test concentration that could be prepareddue to the limited solubility of the test

substance in water).

The EC50 for the reference substance 3,5-dichlorophenol was 20 mg/L and 18 mg/L for the

30-min and the 3-hour exposure times respectively, which is within the specified limits of the

guideline.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The study demonstrated that a saturated solution of ZK 46.072 has no inhibitory effect on
activated sludge from a sewage treatment plant.

Executive summary:

A study on the inhibition ot respiration of activated sludge by 13 -Ethylsecol was performed in the

context ot the evaluation of the potential aquatic hazard . The study was conducted in accordance with OECD Guideline for Testing ot Chemicals No.209.

Cultures of activated sewage sludge were incubated with synthetic sewage under vigorous aeration and in the presence of the test substance. Aeration was interrupted after 30 minutes and again after 3 hours and the rates of respiration measured electrochemically for each culture. Percent inhibition of respiration was calculated for each culture after each contact .

period by comparing oxygen depletion rates for the test substance with those for the negative

control culture. A positive control Le. 3,S-dichlorophenol was tested concurrently with the test

substance in order to demonstrate the satisfactory performance of the procedure.

The EC50 (respiration inhibition) values for 13 -Ethysecol have been determined as >10 mg/L for the 30-minute exposure time and

> 10 mg/L for the 3-hour exposure time (10 mg/L was the highest test concentration that could be prepared due to the limited solubility of the test substance in water).

The EC50 for the reference substance 3,S-dichlorophenol was 20 mg/L and 18 mg/L for the 30-min and the 3-hour exposure times respectively, which is within the specified limits of the guideline.