3,5,5-trimethylcyclohex-2-enone

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Principles of method if other than guideline:

Method: other: OECD Guideline 209 "Activated Sludge, Respiration Inhibition Test", Draft 1.8.83

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- The test item was dissolved in a vehicle = dimethyl sulfoxide/surfactant HCO-40 (4:1)
- Concentration of vehicle: 2.0 g/l
- Other procedures: Synthetic sewage feed: 16 g/l peptone, 11 g/l meat  extract, 3 g/l urea, 0.7 g/l NaCl, 0.4 g/l CaCl2 x 2 H2O, 0.2 g/l MgSO4 x  7 H2O, 2.8 g/l K2HPO4 in dist. water

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

TEST ORGANISMS
- Origin: Gifu-Hokubu Sewage Treatment Plant
- Pretreatment: washing with dist. water >= 3 times, suspended in dist. water at 4 g/l

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 °C

Details on test conditions:

TEST SYSTEM
- Concentrations: at least five, factor 3.2
- Exposure vessel type: 1 l beaker filled as follows: 16 ml sewage feed, stock solution (volume determined by desired concentration), made up to  300 ml with dist. water, 200 ml activated sludge added
- Aeration: 1 l/min with Pasteur pipette
- Control: one each at beginning and end of test series (mean used as  reference in determination of inhibition)

TEST PARAMETER
- oxygen consumption after this procedure, measured over 10  min in 300 ml Erlenmeyer flask; graphical evaluation on log-normal paper

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

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

Remarks:

respiration rate

Validity criteria fulfilled:

not specified

Conclusions:

The EC50 (3 hours) was deterimed as 100 mg/L indicating that the substance does not pose a significant hazard to bacteria populations colonising
sewage sludge.

Executive summary:

A respiration inhibition test according to the draft OECD guideline 209 was conducted with activated sludge from a domestic Sewage Treatment Plant fed with synthetic sewage feed. The respiration rate was measured after a contact time of 3 hours at 5 different concentrations. The following endpoint was derived:

EC50 activated sludge: 100 mg/L

The study was assessed as "reliable with restrictions".

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: Bringmann and Kuehn, Z. Wasser Abwasser Forsch. 10, 87-98 (1977)

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

2.00 g Isophorone were made up to 1 L resulting in a test substance concentration of 2 g/L (stock solution).

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

18 h

Remarks on exposure duration:

+/- 1 hour

Test temperature:

25 +/- 2 °C

pH:

6.9

Nominal and measured concentrations:

200 / 400 / 800 / 1,600 mg/l (nominal)

Details on test conditions:

TEST SYSTEM
- 4 test concentrations
- Number of replicates: 5 growth controls, 4 controls, 3 replicates per test concentration   all performed twice
- Test vessel: 250 ml Erlenmeyer flasks, sterile, capped with cellulophotometric determination of turbidity at 436 nm, graphical evaluation
- the test was conducted twice (test 1 and 2)

EFFECT PARAMETER
- photometric determination of turbidity at 436 nm,  graphical evaluation

Reference substance (positive control):

no

Key result

Duration:

18 h

Dose descriptor:

EC10

Effect conc.:

435 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Mean of test 1 and test 2

Duration:

18 h

Dose descriptor:

EC10

Effect conc.:

530 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Test 2

Duration:

18 h

Dose descriptor:

EC10

Effect conc.:

340 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Test 1

Details on results:

Test 1: EC10 = 340 mg/L
Test 2: EC10 = 530 mg/L
Mean: 435 mg/L

mean EC10 = 435 mg/l

Validity criteria fulfilled:

not specified

Conclusions:

The EC10 (mean value) was determined as 435 mg/L indicating that the test item does not pose a significant risk to Pseudomonas putida.

Executive summary:

The effects of the substance on the growth of the bacterium Pseudomonas putida were evaluated by Hüls AG (1996) in a static test according to the method proposed by Bringmann & Kühn (1977). Four concentrations ranging from 200 to 1600 mg/L were tested over a period of 18 hours. The following endpoints were derived:

EC10 (18 hours, test 1): 340 mg/L

EC10 (18 hours, test 2): 530 mg/L                                   Mean: 435 mg/L

The study was assessed as "reliable with restrictions".

Description of key information

A respiration inhibition test according to the draft OECD guideline 209 was conducted (Yoshioka et al. 1986) with activated sludge from a domestic Sewage Treatment Plant fed with synthetic sewage feed. The respiration rate was measured after a contact time of 3 hours at 5 different concentrations. Another test was conducted with Pseudomonas putida based on a contact time of 18h. Whereas for the first test an EC50 values was derived an EC10 value was given for the second study (Huels AG, 1996)

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

EC10 or NOEC for microorganisms:

435 mg/L

Additional information

EC50 activated sludge: 100 mg/L.

EC10 Pseudomonas putida: 435 mg/L (mean value)

Both studies were assessed as "reliable with restrictions".