2-Propenamide, N-(2-hydroxyethyl)-

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 May 2006 to 26 May 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch number: 050804
Purity: >99%

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: In the laboratory, the sample was maintained under aerobic conditions until required.
- Name and location of sewage treatment plant where inoculum was collected: Worlingworth Sewage treatment works
- Method of cultivation: aliquots (25 mL) of the activated sludge were filtered through dried and prpeweighed filter papers then dried again at 105oC for one hour, allowed to cool in a desiccator and reweighed.
- Preparation of inoculum for exposure:
- Pretreatment: Synthetic sewage (50 ml/L) was added to the sample of activated sludge and the mixture aerated overnight.
- Initial biomass concentration: 4 g/L

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

19.7 to 20.1 ± 2°C

pH:

7.5 to 8.1

Nominal and measured concentrations:

Nominal concentrations; 1, 10 and 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume:
- Aeration:
- No. of vessels per concentration (replicates): 1 or 3
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates):
- No. of vessels per abiotic control (replicates):
- Biomass loading rate: 1.6 g/L

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : rate of oxygen consumption, pH and temperature.

Reference substance (positive control):

yes

Remarks:

3.5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

HEAA was considered to have had no biologically significant inhibitory effect on the respiration rate of actived sludge at any of concentrations employed in the test. The sludge respiration rate was decreased at most by 3% of the mean control in the mixture containing the test substance at 1 mg/L and 2% in one mixture at 100 mg/L.

Results with reference substance (positive control):

The 3h 50% effect concentration EC50 for 3,5-DCP was calculated to be 8.3 mg/L.
The specific respiration rate of the control culture established at the end of test was 97% of rate of that established at start.
These results show that the test was valid and the sample of activated sludge employed was sensitive to inhibition.

Validity criteria fulfilled:

yes

Conclusions:

HEAA was considered to have had no biologically significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. The EC20, EC50 and EC80 of the test substance could not, therefore, be calculated but these must be greater then 100 mg/l, the highest level tested.

Executive summary:

The effect of HEAA on the respiration rate of activated sludge was assessed by OECD Guideline 209, under GLP.

HEAA was considered to have had no biologically significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. The EC20, EC50 and EC80 of the test substance could not, therefore, be calculated but these must be greater then 100 mg/l, the highest level tested.

Description of key information

HEAA had no significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test.The EC20, EC50 and EC80 of the test substance could not, therefore, be calculated but these must be greater than 100 mg/l, the highest level tested.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

The effect of HEAA on the respiration rate of activated sludge was assessed by OECD Guideline 209, under GLP.

HEAA was considered to have had no biologically significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. The EC20, EC50 and EC80 of the test substance could not, therefore, be calculated but these must be greater then 100 mg/l, the highest level tested.