4-[2-[4-[benzylmethyl(ethyl)amino]phenyl]vinyl]-1-(2-hydroxyethyl)pyridinium acetate

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:

28 June 2017 to 28 July 2017

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 (Carbon and Ammonium Oxidation))

GLP compliance:

yes

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION: stock solution was prepared in deionized water (10 g/L) additional dilutions were sone with deionized water

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: from the mixed treatment plant of urban (about 66%) and industrial (about 34%) liquid sewage situated in San Rocco near Monza (Italy)
- Method of cultivation: under aeration
- Preparation of inoculum for exposure: no settlement, sludge was washed and used on day of collection
- Initial biomass concentration: 3 g SS/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20°C ± 2°C

pH:

7.31-7.42 at 6.25-100 mg/L

Nominal and measured concentrations:

pre-test 1, 10 and 100 mg/L
main study: 6.25, 12.5. 25, 50 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass bottles
- Aeration: contimuously
- No. of vessels per concentration (replicates): 5 (3 in pre-test)
- No. of vessels per blank control (replicates): 6 (3 in pre-test)
- No. of vessels per vehicle control (replicates): 5 (3 in pre-test)
- No. of vessels per abiotic control (replicates): 0 (3 in pre-test)
- Sludge concentration (weight of dry solids per volume): 1.5 g/L
- Nutrients provided for bacteria: synthetic sewage feed (as per OECD 209)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water
- Particulate matter: none

OTHER TEST CONDITIONS
- Adjustment of pH: yes with NaOH
- Photoperiod: NA

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : dissolved oxygen concentration over period of 6 minutes leading to calculation of the oxygen consumption rate

Reference substance (positive control):

yes

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

36.74 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- Blank controls oxygen uptake rate: 22.28 mg oxygen per one gram of activated sludge in an hour (pretest 16.79%)
- Coefficient of variation of oxygen uptake rate in control replicates: 8.47% (pretest 0.20%)

Results with reference substance (positive control):

EC50 3,5 Dichlorophenol 6.7 mg/L

Reported statistics and error estimates:

Probit analysis

Concentration	% of inhibition total respiration rate
6.25 mg/l	1.72
12.5 mg/l	11.14
25.0 mg/l	38.70
50.0 mg/l	59.88
100.0 mg/l	86.63

 

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for inhibition of respiration in bacteria from sewage sludge in 36.7 mg/L

Executive summary:

In a test according to OECD 209, bacteria in sewage sludge were exposed to 6.25, 12.5, 25, 50 and 100 mg/L of the substance during 3 hours under continuous aeration. The inhibition of total respiration was measured over a period of 6 minutes. The EC50 was 36.7 mg/L.

Description of key information

In a test according to OECD 209, bacteria in sewage sludge were exposed to 6.25, 12.5, 25, 50 and 100 mg/L of the substance during 3 hours under continuous aeration. The inhibition of total respiration was measured over a period of 6 minutes. The EC50 was 36.7 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

36.7 mg/L