N-[2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyphenyl]acetamide

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:

1999-04-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

1000 mg/L test substance prepared with deionised water to get a stock solution. Stock solution treated for 10 min. in ultrasonic bath for dissolving.
Test concentrations prepared by dilution with test medium (synthetic sewage feed): 25.6, 64, 160, 400 and 1000 mg/L

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: ARA pro Rheno Basel
- Pretreatment: 3 times washed with tap water and addition of synthetic sewage feed one day before the main test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

180 min

Test temperature:

18 - 22°C

pH:

7.8 - 7.9

Nominal and measured concentrations:

25.6, 64, 160, 400, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Aeration: 0.1 - 0.2 L/min
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Sludge concentration (weight of dry solids per volume): 1.56 g/L
- Nutrients provided for bacteria: peptone, meat extract, urea (provided through synthetic sewage feed medium)

EFFECT PARAMETERS MEASURED: respiration inhibition

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

180 min

Dose descriptor:

IC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Key result

Duration:

180 min

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Results with reference substance (positive control):

180 min-IC50: 10 mg/L corresponding to normal sensitivity

Validity criteria fulfilled:

yes

Conclusions:

The test item has a 180-min IC10 of >1000 mg/L based on growth inhibition of activated sludge (determined via respiration rate). The substance is not expected to be inhibitory in wastewater treatment plants when released at much lower expected concentrations.

Description of key information

The IC10 and IC50 (growth inhibition via respiration inhibition) of activated sludge were determined >1000 mg/L, nominal (OECD 209). Disperse Blue 291:1 Br is not considered to be inhibitory to activated sludge.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L