Cyclohexanecarboxylic acid, 1-[[2-(2,5-dimethylphenyl)acetyl]amino]-4-methoxy-, methyl ester, cis-

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Feb 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1988

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

methyl cis-1-{[(2,5-dimethylphenyl)acetyl]amino}-4-methoxycyclohexanecarboxylate

EC Number:

606-524-1

Cas Number:

203313-47-7

Molecular formula:

C19H27NO4

IUPAC Name:

methyl cis-1-{[(2,5-dimethylphenyl)acetyl]amino}-4-methoxycyclohexanecarboxylate

Test material form:

solid: bulk

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

Method: physico-chemical oxygen consumption
Controls: 3.5-Dichlorophenol, Purity 97%.
Test substance concentration: 10, 100, 1000 mg/L
Reference compound concentration: 5, 10 and 20 mg/L

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Type: mixed population of aquatic microorganisms (activated sludge)

Origin: aeration tank of a domestic sewage treatment plant (Municipal STP Cologne-Stammheim)

Microbial inoculum
first, the sludge was settled and the supernatant was decanted after centrifuging (15 min at 4000 rpm and 20°C) the supernatant was decanted approx. 1 g of the wet sludge was dried in order to calculate the amount of wet sludge to achieve a concentration of activated sludge of 3 g/L (dry weight) suspended solids the calculated amount of sludge was first dissolved in synthetic medium and than filled up to a defined end volume with deionised water

pH of the suspension before application: 6.8

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

18.8 - 18.9°C

pH:

7.2 - 7.7

Dissolved oxygen:

Start: 5.3 - 5.5 mg/L
End: 2.6 - 3.1 mg/L

Nominal and measured concentrations:

nominal: 10, 100, 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3.5-Dichlorphenol: 5,10, 20 mg/L

Results and discussion

Effect concentrations

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 total respiration

Remarks:

respiration rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test substance showed 0.0 % respiration inhibition of activated sludge at the highest test item concentration of 1000 mg/L.

Executive summary:

The study was conducted in accordance with Council Directive 67/548/EEC; Annex V, Method C.11 ”Activated sludge respiration inhibition” (1988). This test method is equal to OECD Guideline 209 (1984).

 

Analysis of the respiration rates after 3 hours gave the following values:

Results [mg/L]:

EC 50: > 1000

EC 10: > 1000

The test substance showed 0.0 % respiration inhibition of activated sludge at the highest test item concentration of 1000 mg/L.