undecan-2-one; methyl nonyl ketone

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

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

Data is from secondary source

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

activated sludge, domestic

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 ± 2°C

pH:

7.88 (at the start)

Nominal and measured concentrations:

Test chemical conc. used for the study were 0, 60, 120, 240, 480, 960 mg/l (nominal conc.), respectvely.

Details on test conditions:

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

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol was used as a reference substance.

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

379.49 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

After 3 hours of contact time the inhibition of respiration by the test item was – 2 %, 22 %, 37%, 65 % and 68 % hours for the nominal test concentrations of 60, 120, 240, 480, 960 mg/L respectively.
Respiration rates for the two control vessels were comparable

Results with reference substance (positive control):

The 3 hr EC50 value of the reference substance was determined to be 6.75 mg/l.

Validity criteria fulfilled:

not specified

Conclusions:

Based on the effect of test chemical on respiration inhibition of the test bacteria, the 3 hr EC50 value was determined to be 379.49 mg/l.

Executive summary:

Toxicity to microorganisms study was carried out for 3 hrs. Study was performed in accordance with the OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test. Activated sludge, domestic was used as a test organism. Test inoculum were exposed to different nominal test chemical conc. (i.e., 0, 60, 120, 240, 480, 960 mg/l (nominal conc.)) for a period of 3 hrs. Test trestment was performed in 1 replicate and control system was performed in duplicates. Test conditions involve a temperature of 20 ± 2°C and a pH of 7.88 (at the start), respectively. 3,5-dichlorophenol was used as a reference substance. The 3 hr EC50 value of the reference substance was determined to be 6.75 mg/l. After 3 hours of contact time the inhibition of respiration by the test item was – 2 %, 22 %, 37%, 65 % and 68 % hours for the nominal test concentrations of  60, 120, 240, 480, 960 mg/L respectively. Respiration rates for the two control vessels were comparable. Based on the effect of test chemical on respiration inhibition of the test bacteria, the 3 hr EC50 value was determined to be 379.49 mg/l.

Description of key information

Toxicity to microorganisms study was carried out for 3 hrs (Secondary source, 2008). Study was performed in accordance with the OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test. Activated sludge, domestic was used as a test organism. Test inoculum were exposed to different nominal test chemical conc. (i.e., 0, 60, 120, 240, 480, 960 mg/l (nominal conc.)) for a period of 3 hrs. Test trestment was performed in 1 replicate and control system was performed in duplicates. Test conditions involve a temperature of 20 ± 2°C and a pH of 7.88 (at the start), respectively. 3,5-dichlorophenol was used as a reference substance. The 3 hr EC50 value of the reference substance was determined to be 6.75 mg/l. After 3 hours of contact time the inhibition of respiration by the test item was – 2 %, 22 %, 37%, 65 % and 68 % hours for the nominal test concentrations of 60, 120, 240, 480, 960 mg/L respectively. Respiration rates for the two control vessels were comparable. Based on the effect of test chemical on respiration inhibition of the test bacteria, the 3 hr EC50 value was determined to be 379.49 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

379.49 mg/L

Additional information

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

 

In an experimental study from secondary source, toxicity to microorganisms study was carried out for 3 hrs. Study was performed in accordance with the OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test. Activated sludge, domestic was used as a test organism. Test inoculum were exposed to different nominal test chemical conc. (i.e., 0, 60, 120, 240, 480, 960 mg/l (nominal conc.)) for a period of 3 hrs. Test trestment was performed in 1 replicate and control system was performed in duplicates. Test conditions involve a temperature of 20 ± 2°C and a pH of 7.88 (at the start), respectively. 3,5-dichlorophenol was used as a reference substance. The 3 hr EC50 value of the reference substance was determined to be 6.75 mg/l. After 3 hours of contact time the inhibition of respiration by the test item was – 2 %, 22 %, 37%, 65 % and 68 % hours for the nominal test concentrations of 60, 120, 240, 480, 960 mg/L respectively. Respiration rates for the two control vessels were comparable. Based on the effect of test chemical on respiration inhibition of the test bacteria, the 3 hr EC50 value was determined to be 379.49 mg/l.

 

Another toxicity to microorganisms study was carried out. Tetrahymena pyriformis (ciliate) was used as a test bacteria. Stock solutions of each ketone were prepared in dimethyl sulfoxide (DMSO) at concentrations of 2.5, 5, 10, 25, or 50 parts per million. In all cases, the volume of stock solution added to each test flask did not exceed 0.35 ml, an amount that does not alter Tetrahymena population growth. Chemical was tested in a range-finder prior to testing in duplicate for three additional replicates. Only replicates with control-absorbency values from 0.6 to 0.9 were used in the analyses. Test bacteria were exposed to different test chemical conc. for a period of 2 days. All experiments were performed in duplicates. Population density was measured spectrophotometrically at 540 nm. The 50 percent growth inhibitory concentration, IGC50, was determined for each ketone using Probit Analysis of Statistical Analysis System (SAS) softwareI6 with Y as the absorbency normalized as percentage of control and X as the toxicant concentration in parts per million. Based on the effect on growth inhibition of the test bacteria, the 2 d IC50 value was determined to be 3652.8 mg/l (IC50 = 21.45 mM).

 

In a supporting study from peer reviewed journal and REAXY’s database,toxicity to microorganisms study was carried out. Vibrio fisheri was used as a test bacteria. It was bacteria were cultured to late log-phase growth and harvested. Bacteria was being frozen and maintained at -70°C in solution containing 15% dimethyl sulfoxide (DMSO). Test bacteria was thawed prior to testing and prepared in a 1:10 dilution in 2% NaCl. Stock solutions of each chemical were prepared in DMSO. Two-to-one serial dilutions of test chemical was made using 2% saline solution. Light emission was monitored using a Model 500 Analyzer (Azur Corp., Carlsbad, CA). All experiments were performed in duplicates. The 15-min EC50 values were determined using the Microtox Data Capture and Reporting Program, Version 7.82 (Azur Corp.). On the basis of the effect on growth inhibition of the test bacteria, the 15 mins EC50 value was determined to be 199.52 mg/l and the logarithm of the inverse of 15-min toxicity (pT15) was evaluated to be 2.3, respectively.

 

Additional toxicity to microorganisms study was carried out (Mark T. D. Cronin et. al., 1998). Tetrahymena pyriformis (ciliate) was used as a test bacteria. Study was performed under static conditions for 40 hrs. Population density of test organism Tetrahymena pyriformis was quantified spectrophotometrically. The reported endpoint is the 50% growth inhibitory concentration, IGC50. On the basis of the effect of test chemical on growth inhibition of the test bacteria, the 40 hr IC50 value was determined to be 31.62 mg/l (log(1/IG50) = 1.5).

 

For the test chemical, toxicity to microorganisms study was carried out. Tetrahymena pyriformis (ciliate) was used as a test bacteria. Study was performed under static conditions for 40 hrs. On the basis of the effect of test chemical on growth inhibition of the test bacteria, the 40 hr EC50 value was determined to be 5.76 mg/l.

 

On the basis of the above results, EC50 value of the test chemical was evaluated to be 5.76 to 3652.8 mg/l, respectively.