[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl](2-hydroxypropyl)dimethylammonium chloride

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-08-05

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Version / remarks:

OECD 208, 1984

Deviations:

yes

Remarks:

Valid. crit. (EC50 of ref. substance 3,5-DCP) fulfilled but: only one neg. control sample; test substance only measured after 30 min, not after 3 h → this is however in line with version of OECD 209 that was applicable at that time (OECD 209, 1984)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl]trimethylammonium] methyl sulphate

EC Number:

238-129-1

EC Name:

[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl]trimethylammonium] methyl sulphate

Cas Number:

14254-17-2

Molecular formula:

C19H25ClN5O2.CH3O4S

Constituent 2

Reference substance name:

[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl](2-hydroxypropyl)dimethylammonium chloride

EC Number:

259-033-6

EC Name:

[2-[[4-[(2-chloro-4-nitrophenyl)azo]phenyl]ethylamino]ethyl](2-hydroxypropyl)dimethylammonium chloride

Cas Number:

54229-13-9

Molecular formula:

C21H29ClN5O3.Cl

IUPAC Name:

[2-({4-[(E)-2-(2-chloro-4-nitrophenyl)diazen-1-yl]phenyl}(ethyl)amino)ethyl](2-hydroxypropyl)dimethylazanium chloride

Test material form:

solid

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

not applicable

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: laboratory sewage treatment plant; sludge fed with municipal wastewater
- Pretreatment: no
- Initial biomass concentration: 800 mg/L

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Test conditions

Test temperature:

20 +/- 2 °C

pH:

pH of culture solution prior to testing: 7.4

Nominal and measured concentrations:

Nominal: 0 (control), 10, 18, 32, 56, 100 mg/L;
Abiotic control for chemical oxygen consumption: 10000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-DCP

Results and discussion

Effect concentrations

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

35 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

The EC50 (30 min) of 3,5-dichlorophenol is 15.5 mg/L.

Any other information on results incl. tables

Table 1: Respiration rates of activated sludge exposed to the test item, contact time 30 minutes

Test concentration [mg/L]	Respiration rate [mg O2/L∙h]	Inhibition [%]
10	45.6	8.8
18	37.0	26.0
32	31.5	37.0
56	14.4	71.2
100	4.8	90.4
Control	50.0	-

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (30 min) of the test sample to microorganism originating from predominantly domestic sewage is 35 mg/L.

Executive summary:

The inhibitory effect of the test item to microorganisms originating from sewage sludge of a laboratory STP treating predominantly domestic sewage was investigated after 30 min of exposure at nominal concentrations of 0 (control), 10, 18, 32, 56 and 100 mg/L. The reference substance (positive control) 3,5-dichlorophenol resulted in an EC₅₀ value of 15.5 mg/L. Results with the reference substance were valid.

The present experimental results suggest that the sample tested shows a significant inhibitory effect on the respiration rate of activated sludge after a contact period of 30 minutes. The estimated EC₅₀ value for the sample was 35 mg/L. Considering the actual concentration of the active ingredient in the test sample of 92.7 %, the estimated EC50 value (30 min) for the active ingredient can be calculated as ca. 35 mg/L.