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Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
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:
of read across substance
Justification for type of information:
Data for the target chemical is summarized based on the structurally similar read across chemicals
Reason / purpose:
read-across source
Related information:
Composition 1
Reason / purpose:
read-across source
Related information:
Composition 1
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
WoE report is based on two short term toxicity study of fish for the test chemical :
1. and 2.To evaluate inhibitory effect of test material on aerobic waste-water bacteria.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
IUPAC: 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one
Molecular Formula: C16H8O2S2
Molecular Weight: 296.369 g/mol
Smiles:O=C1c2c(S\C1=C1/Sc3c(cccc3)C1=O)cccc2
InChI:1S/C16H8O2S2/c17-13-9-5-1-3-7-11(9)19-15(13)16-14(18)10-6-2-4-8-12(10)20-16/h1-8H/b16-15-
Test organisms (species):
activated sludge
Details on inoculum:
1 and 2 ) Activated sludge was obtained from a sewage works treating predominantly domestic sewage. The activated sludge may be obtained from a sewage works treating predominantly industrial waste water. The sludge was centrifuged and washed with tap water. This procedure was repeated three times. A small amount of the centrifuged wet sludge was weighed and dried. After drying the ratio R of the weight of the dry solid to that of the wet centrifuged sludge was known. From this ratio R the amount of wet sludge can be calculated which has to be suspended in tap water in order to obtain an activated sludge with a mixed liquor suspended solids level of 4 g dry solids/litre. 50 ml OECD concentrate (2.2) is added to each litre of the activated sludge prepared as described above; this was then aerated overnight in a room at 20°C + 2°C, and kept aerated for use during the day.
Test type:
static
Water media type:
freshwater
Total exposure duration:
3 h
Test temperature:
1 and 2) 20 ± 2°C
pH:
1 and 2) 7-8
Dissolved oxygen:
1 and 2) <2.5 mg/l
Nominal and measured concentrations:
1 and 2) 100 mg/l
Details on test conditions:
1 and 2) - Test vessel: ACTIVATED SLUDGE RESPIRATION RATE APPARATUS
- Type (delete if not applicable): open / closed: No data
- Material, size, headspace, fill volume: 500 ml flask
- Aeration: Yes
- Type of flow-through: "Pasteur" pipette
-Renewal rate of test solution (frequency/flow rate): No data
- No. of organisms per vessel: No data
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates):No data
- Biomass loading rate: No data
Duration:
3 h
Dose descriptor:
IC50
Effect conc.:
> 10 - <= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of total respiration
Validity criteria fulfilled:
not specified
Conclusions:
The test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one is likely to be toxic to microorganism in the concentration range of 10-100 mg/l
Executive summary:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the toxicity of microorganism of the test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one .The studies are as mentioned below:

A screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. The test principle involves measuring the respiration rate of an activated sludge and comparing it with the respiration rate of the same activated sludge under identical conditions, but in the presence of the chemical under test. The test was carried out in activated sludge respiration rate apparatus with constant 20 ± 2°C and pH about 7-8. The test concentration used was 100 mg/l. OECD recommended synthetic sewage was used as feed, while activated sludge was obtained from a sewage works treating predominantly domestic sewage or from a sewage works treating predominantly industrial waste water. The respiration rate of an activated sludge and the respiration rate of activated sludge with test chemical were noted down. In order to calculate the inhibitory effect of a particular chemical at 100 mg/l test concentration its respiration rate is expressed as a percentage of the mean of the two control respiration rates. Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical on activated sludge (aerobic bacteria) is determined to be10 - 100 mg/1 after 3 hrs of exposure.

The test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one is  likely to be toxic to microorganism  in the concentration  range of 10-100 mg/l

Description of key information

Toxicity to microorganism:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the toxicity of microorganism of the test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one .The studies are as mentioned below:

A screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. The test principle involves measuring the respiration rate of an activated sludge and comparing it with the respiration rate of the same activated sludge under identical conditions, but in the presence of the chemical under test. The test was carried out in activated sludge respiration rate apparatus with constant 20 ± 2°C and pH about 7-8. The test concentration used was 100 mg/l. OECD recommended synthetic sewage was used as feed, while activated sludge was obtained from a sewage works treating predominantly domestic sewage or from a sewage works treating predominantly industrial waste water. The respiration rate of an activated sludge and the respiration rate of activated sludge with test chemical were noted down. In order to calculate the inhibitory effect of a particular chemical at 100 mg/l test concentration its respiration rate is expressed as a percentage of the mean of the two control respiration rates. Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical on activated sludge (aerobic bacteria) is determined to be10 - 100 mg/1 after 3 hrs of exposure.

The test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one is  likely to be toxic to microorganism  in the concentration  range of 10-100 mg/l

Key value for chemical safety assessment

Additional information

Toxicity to microorganism:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the toxicity of microorganism of the test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one .The studies are as mentioned below:

A screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. The test principle involves measuring the respiration rate of an activated sludge and comparing it with the respiration rate of the same activated sludge under identical conditions, but in the presence of the chemical under test. The test was carried out in activated sludge respiration rate apparatus with constant 20 ± 2°C and pH about 7-8. The test concentration used was 100 mg/l. OECD recommended synthetic sewage was used as feed, while activated sludge was obtained from a sewage works treating predominantly domestic sewage or from a sewage works treating predominantly industrial waste water. The respiration rate of an activated sludge and the respiration rate of activated sludge with test chemical were noted down. In order to calculate the inhibitory effect of a particular chemical at 100 mg/l test concentration its respiration rate is expressed as a percentage of the mean of the two control respiration rates. Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical on activated sludge (aerobic bacteria) is determined to be10 - 100 mg/1 after 3 hrs of exposure.

The test chemical 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one is  likely to be toxic to microorganism  in the concentration  range of 10-100 mg/l