Cinnamaldehyde

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

Type : mixed population of aquatic microorganism (activated sludge)
Origin :aeration tank of a waste water treatment plant treating predominantly domestic sewage
Pretreatment : aeration of the activated sludge;daily feed with synthetic medium

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Post exposure observation period:

Incubation time : 3 hours with permanent aeration

Nominal and measured concentrations:

Test concentration (mg/l) : 10,18,32,56,100
Test concentration of the activated sludge : 6 g/l
Test substance concentration in physico-chemical oxygen consumption control (mg/l) : 100
Type of application : solution :1 g/l

Details on test conditions:

The respiration rate of an activated sludge is measured after a contact time of 3 hours.The respiration rate of the same activated sludge in the presence of various concentration of the test substance under otherwise identical conditions is also measured.The inhibitory effect of the test substance at a particular concentration is expressed as a percetage of the mean respiration rates of two controls.An EC50 value is calculated from determinations at different concentrations.

Reference substance (positive control):

yes

Remarks:

3.5 -dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

71 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: respiration inhibition

Reported statistics and error estimates:

The EC values are determined by statistical methods (Probit analysis)

Test concentration (mg/l)	Respiratory rate test substance (mg/l.h)	Inhibition (%)
10	30.0	0.0
18	24.0	14.3
32	23.3	16.8
56	15.0	46.4
100	11.1	60.4

 

Test concentrations are given as nominal concentration and have not been confirmed by analytical methods.

Validity criteria fulfilled:

yes

Conclusions:

Based on the effect of test chemical on respiration rate of the test organism activated sludge, the 3 hr EC50 value was determined to be 71 mg/l.

Executive summary:

Toxicity to microorganism study was carried out for 3 hrs. The study was performed in accordance with the ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation). Activated sludge obtained from aeration tank of a waste water treatment plant treating predominantly domestic sewage was used as a test organism. Pretreatment to sludge was given by providing the aeration and feeded with the synthetic medium daily. Nominal test chemical concentrations used for the study were 10, 18, 32, 56 and 100 mg/l, respectively. These chemical concentrations were not verified analytically. Study was performed in a static system for 3 hrs. 3.5 –dichlorophenol in the concentration range of 5 to 30 mg/l was used as a reference substance for the study. The respiration rate of an activated sludge was measured after a contact time of 3 hours. The EC values were determined by Probit analysis. On the basis of the effect of test chemical on respiration rate of the test organism activated sludge, the 3 hr EC50 value was determined to be 71 mg/l.

Description of key information

Toxicity to microorganism study was carried out for 3 hrs (Experimental study report, 1992). The study was performed in accordance with the ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation). Activated sludge obtained from aeration tank of a waste water treatment plant treating predominantly domestic sewage was used as a test organism. Pretreatment to sludge was given by providing the aeration and feeded with the synthetic medium daily. Nominal test chemical concentrations used for the study were 10, 18, 32, 56 and 100 mg/l, respectively. These chemical concentrations were not verified analytically. Study was performed in a static system for 3 hrs. 3.5 –dichlorophenol in the concentration range of 5 to 30 mg/l was used as a reference substance for the study. The respiration rate of an activated sludge was measured after a contact time of 3 hours. The EC values were determined by Probit analysis. On the basis of the effect of test chemical on respiration rate of the test organism activated sludge, the 3 hr EC50 value was determined to be 71 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

71 mg/L

Additional information

Various experimental studies of the test chemical were reviewed for toxicity to microorganism end point which are summarized as below:

 

In an experimental key study, toxicity to microorganism study was carried out for 3 hrs (Experimental study report, 1992). The study was performed in accordance with the ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation). Activated sludge obtained from aeration tank of a waste water treatment plant treating predominantly domestic sewage was used as a test organism. Pretreatment to sludge was given by providing the aeration and feeded with the synthetic medium daily. Nominal test chemical concentrations used for the study were 10, 18, 32, 56 and 100 mg/l, respectively. These chemical concentrations were not verified analytically. Study was performed in a static system for 3 hrs. 3.5 –dichlorophenol in the concentration range of 5 to 30 mg/l was used as a reference substance for the study. The respiration rate of an activated sludge was measured after a contact time of 3 hours. The EC values were determined by Probit analysis. On the basis of the effect of test chemical on respiration rate of the test organism activated sludge, the 3 hr EC50 value was determined to be 71 mg/l.

 

Another toxicity to micro-organism study was carried out for 120 minutes (Secondary source, 2000). Bacteria was used as a test organism. On the basis of effect on growth inhibition of the test organism bacteria, the 120 min EC100 value was determined to be in the range of 1000 to 20000 mg/l.

On the basis of the above results, the 3 hr EC50 value was evaluated to be 71 mg/l.