1-(2,4-dichlorophenyl)ethan-1-one

Toxicity to microorganisms

Administrative data

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: No guideline was followed. No data on GLP.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2001

Materials and methods

Principles of method if other than guideline:

The 2-d ciliate (T. pyriformis) population growth impairment (IGC50) data was determined experimentally by a static 40-h assay. Stock solutions were prepared in dimethyl sulfoxide. Ciliate toxicological assessments were performed following the protocol described by Schultz 1977. The population density was measured spectrophotometrically at 540 nm. Test conditions allow for 8 to 10 cell cycles in control cultures. Test substance was tested in a range finder prior to testing in duplicate for three additional replicates. Two controls, one without test chemical but inoculated with T. pyriformis and the other, a blank with neither test chemical nor ciliates, were used to provide a measure of the test acceptability and as a basis for interpretation of treatment data. Each definitive test replicate consisted of six to eight different concentrations with duplicate flasks of each concentration. Only replicates with control-absorbency values between 0.60 and 0.90 were used in the analyses. The 50% growth inhibition concentration (IGC50) was determined using the probit analysis routine in the Statistical Analysis System (SASt) software. All statistical analyses were performed on nominal concentrations; chemical analyses of concentrations were not performed.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

1-(2,4-dichlorophenyl)ethan-1-one

EC Number:

218-780-8

EC Name:

1-(2,4-dichlorophenyl)ethan-1-one

Cas Number:

2234-16-4

Molecular formula:

C8H6Cl2O

IUPAC Name:

1-(2,4-dichlorophenyl)ethan-1-one

Details on test material:

- Name of test material (as cited in study report): 2,4-Dichloroacetophenone
- Purity: 95% or greater and was not repurified prior to use.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

yes

Details on test solutions:

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): dimethyl sulfoxide.

Test organisms

Test organisms (species):

Tetrahymena pyriformis

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

40 h

Test conditions

Nominal and measured concentrations:

Six to eight different concentrations with duplicate flasks of each concentration.
No details reported.

Details on test conditions:

TEST CONCENTRATIONS
- Range finding study: The test substance was tested in a range finder prior to testing in duplicate for three additional replicates. Two controls, one without test chemical but inoculated with T. pyriformis and the other, a blank with neither test chemical nor ciliates, were used to provide a measure of the test acceptability and as a basis for interpretation of treatment data. Each definitive test replicate consisted of six to eight different concentrations with duplicate flasks of each concentration.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Population density, spectrophotometrically measured at 540 mm.

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Key result

Duration:

40 h

Dose descriptor:

other: log (1/inhibitory growth concentration [IGC50])

Effect conc.:

0.62 mmol/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Reported statistics and error estimates:

The 50% growth inhibition concentration (IGC50) was determined using the probit analysis routine in the Statistical Analysis System (SASt) software.

Any other information on results incl. tables

Log (1/LC50) = 0.62 mmol/L

LC50 = 0.239 mmol/L

LC50 = 45.18 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The log (1/inhibitory growth concentration [IGC50]) for 40h exposure of the test substance was reported to be 0.62 mmol/L (45.18 mg/L) in Tetrahymena pyriformis.

Executive summary:

The 2-d ciliate (Tetrahymena pyriformis) population growth impairment (IGC50) data was determined experimentally by a static 40-h assay. Stock solutions were prepared in dimethyl sulfoxide. Ciliate toxicological assessments were performed following the protocol described by Schultz 1977. The population density was measured spectrophotometrically at 540 nm. Test conditions allow for 8 to 10 cell cycles in control cultures. Test substance was tested in a range finder prior to testing in duplicate for three additional replicates. Two controls, one without test chemical but inoculated with T. pyriformis and the other, a blank with neither test chemical nor ciliates, were used to provide a measure of the test acceptability and as a basis for interpretation of treatment data. Each definitive test replicate consisted of six to eight different concentrations with duplicate flasks of each concentration. Only replicates with control-absorbency values between 0.60 and 0.90 were used in the analyses. The 50% growth inhibition concentration (IGC50) was determined using the probit analysis routine in the Statistical Analysis System (SASt) software. All statistical analyses were performed on nominal concentrations; chemical analyses of concentrations were not performed. The log (1/inhibitory growth concentration [IGC50]) for 40h exposure of the test substance was reported to be 0.62 mmol/L (~45.18 mg/L) in Tetrahymena pyriformis.