2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from Peer reviewed journal

Data source

Reference

Reference Type:

publication

Title:

THE ASSESSMENT OF THE POSSIBLE INHIBITORY EFFECT OF DYESTUFFS ON AEROBIC WASTE-WATER BACTERIA EXPERIENCE WITH A SCREENING TEST

Author:

Dr. D. Brown, Dr. H.R. Hitz, Dr. L. Schafer

Year:

1981

Bibliographic source:

Chemosphere, Vol. I0, No. 3, PP 245 - 261, 1981

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Activated sludge respiration inhibition test: 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.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

EC Number:

208-096-8

EC Name:

3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

Cas Number:

509-34-2

Molecular formula:

C28H30N2O3

IUPAC Name:

3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one

Test material form:

solid

Details on test material:

- Name of the test material: 3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one
- Molecular formula: C28H30N2O3
- Molecular weight: 442.556 g/mol
- Substance type: Organic
- Smiles: C12(c3c(Oc4c1ccc(c4)N(CC)CC)cc(N(CC)CC)cc3)c1c(cccc1)C(O2)=O
- Physical State: Solid

Specific details on test material used for the study:

- Name of the test material: 3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one
- Molecular formula: C28H30N2O3
- Molecular weight: 442.556 g/mol
- Substance type: Organic
- Smiles: C12(c3c(Oc4c1ccc(c4)N(CC)CC)cc(N(CC)CC)cc3)c1c(cccc1)C(O2)=O

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

No data

Test solutions

Vehicle:

yes

Details on test solutions:

No data

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

Where possible activated sludge should be obtained from a sewage works treating predominantly domestic sewage. If this is not convenient, the activated sludge may be obtained from a sewage works treating predominantly industrial waste water. On the return to the laboratory, the sludge is centrifuged and washed with tap water. This procedure is repeated three times. A small amount of the centrifuged wet sludge is weighed and dried. After drying the ratio R of the weight of the dry solid to that of the wet centrifuged sludge is 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 is then aerated overnight in a room at 20°C + 2°C, and kept aerated for use during the day. If the same sludge has to be used on subsequent days (up to a maximum of 4) a further 50 ml/litre of OECD concentrate sewage is added at the end of each working day.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test conditions

Hardness:

No data

Test temperature:

20 ± 2°C

pH:

7-8

Dissolved oxygen:

<2.5 mg/l

Salinity:

No data

Conductivity:

No data

Nominal and measured concentrations:

100 mg/l

Details on test conditions:

- 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

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

For those chemicals whose respiration rate is at least 80% of the control, the IC50 (concentration for 50% inhibition of respiration rate) is recorded as 100 mg/l.

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

No data

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one on activated sludge (aerobic bacteria) is determined to be >100 mg/1 after 3 hrs of exposure.

Executive summary:

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. For those chemicals whose respiration rate is at least 80% of the control, the IC50 (concentration for 50% inhibition of respiration rate) is recorded as >100 mg/l.

Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one on activated sludge (aerobic bacteria) is determined to be >100 mg/1 after 3 hrs of exposure.