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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:
for read across
Justification for type of information:
Data for the target chemical is summarized based on the structurally similar read across chemicals
Reason / purpose:
read-across: supporting information
Reason / purpose:
read-across: supporting information
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
WoE report is based on two toxicity study of microorganism for the test chemical :
2) To study the toxicity of test material to the Marine Dinoflagellate Gymnodinium breve
3)To evaluate antibacterial activity of Benzoic acid on Activated sludge
GLP compliance:
not specified
Details on sampling:
3) - Concentrations: 0,1,10, 20, 50, 100, 200, 500, 1000 and 1000 ppm
- Sampling method: Potassium hydrogen phthalate is prepared by 1% solutions of these compounds in distilled water, i.e. 1.0 g of the compound in I00 ml of distilled water.
- Sample storage conditions before analysis: Test portions were placed in a single row in test tube racks which were placed 2 inches from 40-watt, cool-white fluorescent lights (incident light ca. I000 foot-candles) in a 25˚ constant room temperature. Special care was taken to insure uniform light on test portions to avoid variability of relative chlorophyll a values.
Test organisms (species):
other: 2) Activated sludge 3)Dinoflagellate Gymnodinium breve
Details on inoculum:
2) PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: test material is prepared by 1% solutions of these compounds in distilled water, i.e. 1.0 g of the compound in I00 ml of distilled water.
- Controls: Yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): distilled water
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 0.1, 0.2, 0.5, 1.0 ml in distilled water.
Test type:
static
Water media type:
freshwater
Total exposure duration:
96 h
Test temperature:
25˚C
pH:
7.6
Details on test conditions:
2) TEST SYSTEM
- Test vessel: Artificial sea water medium--NH-15.
- No. of organisms per vessel: 1000 and 5000 G. breve per milliliter.
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 2
- Biomass loading rate: The cultures contained between 1000 and 5000 G. breve per milliliter at the time the assays were started.

OTHER TEST CONDITIONS
- Adjustment of pH: Yes, pH 4.2 adjusted to pH 7.6
- Photoperiod: Constant
- Light intensity: cool-white fluorescent lights (incident light ca. I000 foot-candles)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Relative chlorophyll a values were observed.
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
not specified
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
498.52 - <= 997 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Details on results:
1) - Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The pH of these media (4.2) to be responsible, thus an additional assay was carried out in which the pH of the one percent solution of potassium hydrogen phthalate was adjusted to 7.6 with potassium hydroxide (yielding the dipotassium salt in situ) before adding aliquots to the culture portions.This adjustment alleviated the observed toxicity.
Reported statistics and error estimates:
1)Values were obtained by plotting on semilog paper the concentration of test material (ppm) versus the growth rate (linear axis of graph), expressed as a percentage of the growth of a "no-add" control. The concentration values (ppm) which caused a 50 percent growth reduction.
Conclusions:
The test chemical is not likely to be toxic to microorganism atleast in the concentration range of 498 - 1000 mg/l
Executive summary:

Data available for the test chemicals has been reviewed to determine the toxicity of microorganism of the test chemical .The studies are as mentioned below:

2)Test material was used as a test material to evaluate toxicity to microorganisms as per OECD guideline 209. Activated sludge was used as the test culture at pH 7.5 for 3 h The EC50 value on the basis of respiration inhibition test was observed to be >1000 mg/l.

3)In a study of toxicity of test mateial to the Marine Dinoflagellate Gymnodinium breve the effect of test material was evaluated. The test substance was tested in a concentration of 0,1,10, 20, 50, 100, 200, 500, 1000 and 1000 ppm. The results show Median growth when concentration of test material (ppm) versus the growth rate (linear axis of graph), expressed as a percentage of the growth of a "no-add" control at 498.52 and 997 mg/l. Therefore, EC50 of test material was considered to be be 498.52 and 997 mg/l when tested on Marine Dinoflagellate Gymnodinium breve for 96 hours.

Description of key information

Toxicity to microorganism:

Data available for the test chemicals has been reviewed to determine the toxicity of microorganism of the test chemical .The studies are as mentioned below:

2)Test material was used as a test material to evaluate toxicity to microorganisms as per OECD guideline 209. Activated sludge was used as the test culture at pH 7.5 for 3 h The EC50 value on the basis of respiration inhibition test was observed to be >1000 mg/l.

3)In a study of toxicity of test mateial to the Marine Dinoflagellate Gymnodinium breve the effect of test material was evaluated. The test substance was tested in a concentration of 0,1,10, 20, 50, 100, 200, 500, 1000 and 1000 ppm. The results show Median growth when concentration of test material (ppm) versus the growth rate (linear axis of graph), expressed as a percentage of the growth of a "no-add" control at 498.52 and 997 mg/l. Therefore, EC50 of test material was considered to be be 498.52 and 997 mg/l when tested on Marine Dinoflagellate Gymnodinium breve for 96 hours.

Key value for chemical safety assessment

EC50 for microorganisms:
498.52 mg/L

Additional information

Toxicity to microorganism:

Data available for the test chemicals has been reviewed to determine the toxicity of microorganism of the test chemical .The studies are as mentioned below:

2)Test material was used as a test material to evaluate toxicity to microorganisms as per OECD guideline 209. Activated sludge was used as the test culture at pH 7.5 for 3 h The EC50 value on the basis of respiration inhibition test was observed to be >1000 mg/l.

3)In a study of toxicity of test mateial to the Marine Dinoflagellate Gymnodinium breve the effect of test material was evaluated. The test substance was tested in a concentration of 0,1,10, 20, 50, 100, 200, 500, 1000 and 1000 ppm. The results show Median growth when concentration of test material (ppm) versus the growth rate (linear axis of graph), expressed as a percentage of the growth of a "no-add" control at 498.52 and 997 mg/l. Therefore, EC50 of test material was considered to be be 498.52 and 997 mg/l when tested on Marine Dinoflagellate Gymnodinium breve for 96 hours.