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Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms, other
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data is from peer reviewed journal
Justification for type of information:
Data is from peer reviewed journal
Qualifier:
according to guideline
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Toxicity to microorganism study was carried out.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
yes
Remarks:
dimethyl sulfoxide (DMSO) was used as a vehicle.
Test organisms (species):
Tetrahymena pyriformis
Test type:
static
Water media type:
freshwater
Total exposure duration:
40 h
Details on test conditions:
TEST SYSTEM
- Test vessel: Flasks were used as a test vessel.
- No. of vessels per concentration (replicates): Duplicates
- Other: Two control vessels, one control with no test chemical but inoculated with T. pyriformis, and the other, a blank control, which has neither test chemical nor test organism were run simultaneously during the study.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Population density of test organism was measured spectrophotometrically at 540 nm.

TEST CONCENTRATIONS
- Range finding study: yes, range finding study was performed in duplicates prior to the initiation of study.
Reference substance (positive control):
not specified
Key result
Duration:
40 h
Dose descriptor:
other: IGC50
Effect conc.:
204.64 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Reported statistics and error estimates:
The 50% growth inhibitory concentrations, IGC50, were determined by Probit Analysis of Statistical Analysis System (SAS) software

Table: Toxicity of test chemical result.

 

Chemical

Log 1/IGC50

logKow (1-octanol/water)

Test chemical

-0.08

2.47

Validity criteria fulfilled:
not specified
Conclusions:
Based on effect on growth inhibition of the test organism Tetrahymena pyriformis, the 40 hr IGC50 value was determined to be 204.64 mg/l.
Executive summary:

Toxicity to microorganism study was performed using Tetrahymena pyriformis as a test organism. The study was carried out under static conditions. Stock solutions of test chemical were prepared in dimethyl sulfoxide. Exact test chemical concentrations used for the study was not known, but each test replicate consists of six to eight different concentrations. Range finding study was performed in duplicates prior to the initiation of study. Flasks were used as a test vessel. To each test flask were added test organism and a solution of test chemical. Two control vessels, one control with no test chemical but inoculated with T. pyriformis, and the other, a blank control, which has neither test chemical nor test organism were run simultaneously during the study. All test concentrations experiments were performed in duplicates. Test conditions allow for 8-9 cell cycles in control cultures. Only replicates with control-absorbency values > 0.6 but < 0.75 were used for the analysis. Population density of test organism was measured spectrophotometrically at 540 nm. The 50% growth inhibitory concentrations, IGC50, were determined by Probit Analysis of Statistical Analysis System (SAS) software. On the basis of the effect on growth inhibition of the test organism Tetrahymena pyriformis, the 40 hr IGC50 value was determined to be 204.64 mg/l.

Description of key information

Toxicity to microorganism study was performed using Tetrahymena pyriformis as a test organism (T. W. Schultz et. al., 1999 and authoritative database, 2012). The study was carried out under static conditions. Stock solutions of test chemical were prepared in dimethyl sulfoxide. Exact test chemical concentrations used for the study was not known, but each test replicate consists of six to eight different concentrations. Range finding study was performed in duplicates prior to the initiation of study. Flasks were used as a test vessel. To each test flask were added test organism and a solution of test chemical. Two control vessels, one control with no test chemical but inoculated with T. pyriformis, and the other, a blank control, which has neither test chemical nor test organism were run simultaneously during the study. All test concentrations experiments were performed in duplicates. Test conditions allow for 8-9 cell cycles in control cultures. Only replicates with control-absorbency values > 0.6 but < 0.75 were used for the analysis. Population density of test organism was measured spectrophotometrically at 540 nm. The 50% growth inhibitory concentrations, IGC50, were determined by Probit Analysis of Statistical Analysis System (SAS) software. On the basis of the effect on growth inhibition of the test organism Tetrahymena pyriformis, the 40 hr IGC50 value was determined to be 204.64 mg/l.

Key value for chemical safety assessment

Additional information

Toxicity to microorganism study was performed using Tetrahymena pyriformis as a test organism (T. W. Schultz et. al., 1999 and authoritative database, 2012). The study was carried out under static conditions. Stock solutions of test chemical were prepared in dimethyl sulfoxide. Exact test chemical concentrations used for the study was not known, but each test replicate consists of six to eight different concentrations. Range finding study was performed in duplicates prior to the initiation of study. Flasks were used as a test vessel. To each test flask were added test organism and a solution of test chemical. Two control vessels, one control with no test chemical but inoculated with T. pyriformis, and the other, a blank control, which has neither test chemical nor test organism were run simultaneously during the study. All test concentrations experiments were performed in duplicates. Test conditions allow for 8-9 cell cycles in control cultures. Only replicates with control-absorbency values > 0.6 but < 0.75 were used for the analysis. Population density of test organism was measured spectrophotometrically at 540 nm. The 50% growth inhibitory concentrations, IGC50, were determined by Probit Analysis of Statistical Analysis System (SAS) software. On the basis of the effect on growth inhibition of the test organism Tetrahymena pyriformis, the 40 hr IGC50 value was determined to be 204.64 mg/l.

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