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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms, other
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
experimental data of read across substances
Justification for type of information:
Data for the target chemical is summarized based on the structurally similar read across chemicals
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
other: as mentioned below
Principles of method if other than guideline:
WoE report is based on two toxicity to microorganism studies as-
WoE 2. and WoE 3.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
not specified
Details on test solutions:
WoE 2: Test chemical concentrations used for the study was in the range of 500–5000 mg/L (nominal concentration).
WoE 3: Concentrations: The test chemical conc. used for the study was 1000 mg/l (0.1%) and 10000 mg/l (1%)

Test organisms (species):
other: WoE 2: Vibrio fisheri and WoE 3: Paramaecium caudatum
Test type:
static
Water media type:
saltwater
Limit test:
no
Total exposure duration:
30 min
Remarks on exposure duration:
WoE 2: 30 mins and WoE 3: After 20 mins, the mean survival time and the death rate was calculated.
Test temperature:
WoE 2: 20°C
WoE 3: no data available
Nominal and measured concentrations:
WoE 2: Test chemical concentrations used for the study was in the range of 500–5000 mg/L (nominal concentration).
WoE 3: The test chemical conc. used for the study was 1000 mg/l (0.1%) and 10000 mg/l (1%) (nominal concentrations)
Details on test conditions:
WoE 2: no data available

WoE 3:
TEST SYSTEM
Test vessel: Hollow slide glass
No. of organisms per vessel: 30 to 40 test organism for each test conc. was taken for the study.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): After 20 mins, the mean survival time and the death rate was calculated.

TEST CONCENTRATIONS
Test concentrations: 10000 mg/l (1%) and 1000 mg/l (0.1%) (Nominal concentrations)

Reference substance (positive control):
not specified
Duration:
0.5 min
Dose descriptor:
EC50
Effect conc.:
2 430 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition % of light production
Remarks on result:
other: WoE 2: EC50 value was reported as 2403 ± 17 mg/l
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
1 375 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition % of light production
Remarks on result:
other: WoE 2: EC50 value was reported as 1375 ± 46 mg/l
Duration:
20 min
Dose descriptor:
other: EC77.4
Effect conc.:
10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: mortality
Remarks on result:
other: WoE 3: The death rate of test organism was found to be 77.4%.

WoE 2: no data available

WoE 3:

The mean survival time (in sec) of test organismParamecium caudatumwas determined to be 695 seconds.

 

Table 1:EFFECT OF TEST CHEMICAL ON THE MEAN SURVIVAL TIME AND DEATH RATE OF Paramecium caudatum

 

Test chemical

Dye concentration

1.0%

0.1%

Mean survival time

(sec)

Death rate

(%)

Mean survival time

(sec)

Death rate

(%)

Test chemical

695

77.4

-*

3.3

-* indicates no deaths were observed for 20 minutes

Validity criteria fulfilled:
not specified
Conclusions:
On the basis of the experimental studies of the read across chemical and applying the weight of evidence approach and by evaluating the effect of test chemical on test organism, the 30 mins EC50 value can be expected to be 1375 mg/l.
Executive summary:

Data available of the read across chemicals has been reviewed to determine the effect of the test chemical on toxicity to microorganisms. The studies are as mentioned below:

Toxicity to micro-organism study was carried out for 30 mins. For assessing the effect of test chemical on test organism,  Kinetic bioluminescence test ‘‘flash test’’ was carried out. Vibrio fisheri was used as a test organism. Test chemical concentrations used for the study was in the range of 500–5000 mg/L (nominal concentration). During the first 5 sec after adding the batcerial suspension to the test chemical, the peak luminescence value was obtained. Kinetic measurement was performed with a 125 l Luminometer at 20°C. The results were calculated as the inhibition percentage of light productiom and expressed using the corresponding EC50 values. On the basis of the effect of test chemical on the inhibition in percentage of light production of the test organism Vibrio fisheri, the 0.5 min and 30 min EC50 value was determined to be 2403 ± 17 mg/l and 1375 ± 46 mg/l , respectively.

For the test chemical, toxicity to micro-organism study was carried out for 20 mins. Paramaecium caudatum was used as a test organism. The test organismParamecium caudatumwas maintained at 22°C on 0.15% dried lettuce infusion and fed withAerobacter aerogenes.Test chemical conc. used for the study was 1000 mg/l (0.1%) and 10000 mg/l (1%). The test concentrations were put in a hollow slide glass, and an equal volume of 0.04 M phosphate buffer, pH 7.0, was added. After 5 to 10 test organisms were added, their survival times were measured microscopically. Thirty to forty test organisms for each concentration were tested by the same method, and the mean survival time and the death rate were calculated. The survival time was defined as the time required until death was observed for each concentration. Death was assumed to have occurred when there was no movement. The death rate was defined as the percentage of deaths observed during 20 minutes. The mean survival time (in sec) of test organismParamecium caudatumwas determined to be 695 seconds.  The death rate of the test organism at 10000 mg/l was 77.4%. Thus, based on effect on mortality of the test organism Paramecium caudatum, the EC77.4 value was determined to be 100000 mg/l.

On the basis of the experimental studies of the read across chemical and applying the weight of evidence approach and by evaluating the effect of test chemical on test organism, the 30 mins EC50 value can be expected to be 1375 mg/l.

Description of key information

On the basis of the experimental studies of the read across chemical and applying the weight of evidence approach and by evaluating the effect of test chemical on test organism, the 30 mins EC50 value can be expected to be 1375 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:
1 375 mg/L

Additional information

Data available of the read across chemicals has been reviewed to determine the effect of the test chemical on toxicity to microorganisms. The studies are as mentioned below:

 

Toxicity to micro-organism study was carried out for 30 mins. For assessing the effect of test chemical on test organism, Kinetic bioluminescence test ‘‘flash test’’ was carried out. Vibrio fisheri was used as a test organism. Test chemical concentrations used for the study was in the range of 500–5000 mg/L (nominal concentration). During the first 5 sec after adding the batcerial suspension to the test chemical, the peak luminescence value was obtained. Kinetic measurement was performed with a 125 l Luminometer at 20°C. The results were calculated as the inhibition percentage of light productiom and expressed using the corresponding EC50 values. On the basis of the effect of test chemical on the inhibition in percentage of light production of the test organism Vibrio fisheri, the 0.5 min and 30 min EC50 value was determined to be 2403 ± 17 mg/l and 1375 ± 46 mg/l , respectively.

 

For the test chemical, toxicity to micro-organism study was carried out for 20 mins. Paramaecium caudatum was used as a test organism. The test organismParamecium caudatumwas maintained at 22°C on 0.15% dried lettuce infusion and fed withAerobacter aerogenes.Test chemical conc. used for the study was 1000 mg/l (0.1%) and 10000 mg/l (1%). The test concentrations were put in a hollow slide glass, and an equal volume of 0.04 M phosphate buffer, pH 7.0, was added. After 5 to 10 test organisms were added, their survival times were measured microscopically. Thirty to forty test organisms for each concentration were tested by the same method, and the mean survival time and the death rate were calculated. The survival time was defined as the time required until death was observed for each concentration. Death was assumed to have occurred when there was no movement. The death rate was defined as the percentage of deaths observed during 20 minutes. The mean survival time (in sec) of test organismParamecium caudatumwas determined to be 695 seconds.  The death rate of the test organism at 10000 mg/l was 77.4%. Thus, based on effect on mortality of the test organism Paramecium caudatum, the EC77.4 value was determined to be 100000 mg/l.

 

On the basis of the experimental studies of the read across chemical and applying the weight of evidence approach and by evaluating the effect of test chemical on test organism, the 30 mins EC50 value can be expected to be 1375 mg/l.