2-Propen-1-one, 3-(dimethylamino)-1-(3-pyridinyl)-

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 31, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

434-770-8

EC Name:

-

Cas Number:

55314-16-4

Molecular formula:

C10 H12 N2 O1

IUPAC Name:

3-(dimethylamino)-1-(pyridin-3-yl)prop-2-en-1-one

Details on test material:

Name of test material (as cited in study report): STI571 Y5a
- Substance type: Brown solid
- Physical state: Solid
- Analytical purity: 98.6%
- Lot/batch No.: 992301
- Expiration date of the lot/batch: 01 July 2001
- Stability under storage conditions: Stable
- Storage condition of test material: In refrigerator in the dark
- Solubility in water: Not indicated

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

Since STI571 Y5A is well soluble in water a stock solution of 5 g/l was prepared in milli-Q water.
Thorough mixing was used to accelerate dissolving and to ensure homogeneity.
The pH of the clear orange, slightly foaming, stock solution was 10.3.
Five concentrations were tested: 100, 180, 320, 560 and 1000 mg/l, corresponding to 10, 18, 32, 56 and 100 ml of the prepared stock solution in 500 ml final volume

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge was coarsely sieved, washed and diluted with tap water. A small amount of the sludge was weighed and dried at ca. 105°C to determine the amount of suspended solids (3.2 g/l of sludge). Before use the pH was checked (measured value: 7.8). The batch of sludge was used on subsequent days (maximum four days). Therefore 50 ml of synthetic sewage feed was added to each litre of activated sludge at the end of each working day. The sludge was kept aerated at test temperature until use.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

Oxygen consumption was measured and recorded for approximately 10 minutes after the 3 hours exposure period

Test conditions

Test temperature:

The temperature of the test medium was 20°C.

pH:

Between 7.7 and 7.8

Dissolved oxygen:

Oxygen consumption:
Controls reference substance series: 54-56 mg/ O2/l/h
Reference substance 3, 5 Dichlorophenol:9-51 mg O2/l/h
Controls STI571 Y5A series:50-56 mg O2/l/h
STI571 Y5A Series:45-60 mg O2/l/h

The oxygen concentration at the start of measurement was at least 6.6 mg O2/l

Nominal and measured concentrations:

Nominal concentration: 0, 100, 180, 320, 560 and 1000 mg/l

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: All glass, approximately 300 ml oxygen bottles (measuring) and
500 litre test bottles(exposure)
- Aeration:During exposure with clean, oil-free air
- No. of vessels per concentration (replicates):1
- No. of vessels per control (replicates):2/ series
- Biomass loading rate:1.28 g/l suspended solids in final test mixture

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis (Milli-RO
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The respiration rate from each vessel, in mg O2/l/hr, was calculated from the linear part of the respiration curve, which was generally between 2.5 and 6.5 mg O2/l.

TEST CONCENTRATIONS
- Test concentrations:0, 100, 180, 320, 560 and 1000 mg/l

Reference substance (positive control):

yes

Remarks:

3.5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

No inhibition in respiration rate of the sludge was recorded at 100 and 180 mg STI571 Y5A per litre. At higher concentrations very slight inhibition in respiration rate of the sludge was recorded.
No dose dependent increase in inhibition was observed at the three highest concentrations tested. Inhibition in respiration rate of the sludge levelled-off at approximately 15%, which was reached at exposure to 320 mg/l and higher. Hence, the EC50 for STI571 Y5A exceeded 1000 mg/l, the highest concentration tested.

Results with reference substance (positive control):

Results with reference substance valid: Yes
The inhibitory effect of 3,5-dichlorophenol on aerobic waste water (activated sludge) bacteria increased with increased with increasing concentration , ranging from a 31 % inhibition at 3.2 mg/l to 84% at 32 mg/l.
Relevant effects levels: The EC50 of 3,5-dichlorophenol was: 7.3 mg/l

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Although STI571 Y5A was slightly toxic to waste water (activated sludge) bacteria in this present test, the EC50-value was not reached up to 1000 mg/l. The inhibitory effect of STI571 Y5A on aerobic waste water (activated sludge) bacteria appeared to level off at approximately 15%, which was reached at 320 mg/l and higher.