4-trans-(4-trans-Propylcyclohexyl)-cyclohexancarbonic acid

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:

1996-08-05 to 1996-08-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: direct weighing in

Test organisms (species):

activated sludge

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: laboratory plant treating predominantly municipal sewage (Südlicher Wupperverband)
- Pre-treatment: no
- pH of the culture solution before measuring the consumption : 6.5
- Initial biomass concentration: 800 mg/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Test temperature:

20 ± 2 °C

pH:

7.3 - 7.5

Nominal and measured concentrations:

Nominal conc.: 1000, 1800, 3200, 5600, 10000 mg/L;
no measured concentration.

Details on test conditions:

TEST SYSTEM
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2

TEST CONCENTRATIONS
1000, 1800, 3200, 5600, 10000 mg/L
Abiotic control: 10000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol, purity 99 %

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: EC50 = 8.8 mg/L

 Results reference substance (3,5-dichlorophenol):

Concentration [mg/L]	Respiration rate [mg/L.h]	Inhibition [%]
2.5	40.0	20.5
5	40.8	18.9
10	27.0	46.3
20	9.0	81.1
40	1.5	97.0

 

Results test substance

Concentration [mg/L]	Respiration rate [mg/L.h]	Inhibition [%]
1000	34.8	30.8
1800	36.0	28.4
3200	31.2	38.0
5600	33.0	34.4
10000	34.5	31.4

 

Validity criteria fulfilled:

yes

Conclusions:

After 30 min of exposure the EC50 was determined to be > 10000 mg/L.

Executive summary:

The influence of the test item on the respiration rate of activated sludge was investigated after a contact time of 30 minutes in a study similar to OECD TG 209. Five concentrations were tested: 1000, 1800, 3200, 5600 and 10000 mg/L, while the abiotic control was run at the highest test substance concentration of 10000 mg/L. 3,5-dichlorophenol was used as the reference substance. After the 30-minutes exposure duration, for the reference substance 3,5-dichlorophenol an EC₅₀ value of 8.8 mg/L was determined. The determination was carried out using a Probit analysis. Based on the measurement results, the test item showed a 31.4 % inhibition of the respiration of activated sludge at an application concentration of 10000 mg/L. Thus, the EC₅₀ was determined to be > 10000 mg/L.

Description of key information

A test on respiration inhibition using activated sludge of a predominantly domestic sewage treatment plant was conducted in a method similar to OECD 209. After 30 min of exposure the EC₅₀ was determined to be > 10000 mg/L (reference 6.1.7-1).

Additional information

The influence of the test item on the respiration rate of activated sludge was investigated after a contact time of 30 minutes in a study similar to OECD guideline 209. Five concentrations were tested: 1000, 1800, 3200, 5600 and 10000 mg/L, while the abiotic control was run at the highest test substance concentration of 10000 mg/L. 3,5-dichlorophenol was used as the reference substance. After the 30-minutes exposure duration, for the reference substance 3,5-dichlorophenol an EC₅₀ value of 8.8 mg/L was determined. The determination was carried out using a probit analysis. Based on the measurement results, the test item shows a 31.4 % inhibition of the respiration of activated sludge at an application concentration of 10000 mg/L. Thus, the EC₅₀ was determined to be > 10000 mg/L.