N-benzylprop-2-enamide

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:

26 October 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Qualifier:

equivalent or similar to guideline

Guideline:

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

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

yes

Remarks:

water

Details on test solutions:

A 0.5 g/L solution was prepared by adding 125.0 mg to 250 mL water (purified by reverse osmosis). After thorough mixing, the solution was treated by ultrasonication (10 min) and magnetic stirring (32 min). This resulted in a clear and colourless solution that was added to the medium.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Municipal Sewage Treatment Plant Waterschap De Maaskant, 's-Hertogenbosch
- Preparation of inoculum for exposure: sieved, washed and diluted with ISO-medium stored overnight (fed with 50 mg/L synthetic sewage feed) with aeration at 18 ˚C.
- Pretreatment: none
- Initial biomass concentration: SS 3.7 g/L

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Post exposure observation period:

oxygen consumption measured over a 10 min period

Test temperature:

18.0-18.8 ˚C

pH:

sludge: 7.8
test vessels: 8.2

Dissolved oxygen:

constant aeration during exposure

Nominal and measured concentrations:

100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 1L glass vessel (300 mL oxygen bottles)
- Aeration: yes
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2 (one analysed before and one after the test substance)
- Sludge concentration (weight of dry solids per volume): 3.7 g/L SS
- Nutrients provided for bacteria: 16 mL synthetic sewage feed according to the guideline
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: adjusted ISO-medium according to the guideline
OTHER TEST CONDITIONS
- Adjustment of pH: none
EFFECT PARAMETERS MEASURED: oxygen consumption

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Details on results:

see attachment
The difference between controls was 10% (< 15%)

Results with reference substance (positive control):

3,5-dichlorophenol as tested in the same test showed respiration inhibition of 49% at 5 mg/L and 83% at 30 mg/L. Therefore the EC50 is between the ranges of 5 and 30 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for inhibtion of respiration is > 100 mg/L

Executive summary:

In a respiration inhibition test the substance showed slight inhibition of the oxygen consumption of sludge (10 and 14% in duplicates) compared to controls. The EC50 is > 100 mg/L.

Description of key information

In a respiration inhibition test the substance showed slight inhibition of the oxygen consumption of sludge (10 and 14% in duplicates) compared to controls. The EC50 is > 100 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L