4-aminoazobenzene

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study, non-GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-aminoazobenzene

EC Number:

200-453-6

EC Name:

4-aminoazobenzene

Cas Number:

60-09-3

Molecular formula:

C12H11N3

IUPAC Name:

4-[(E)-2-phenyldiazen-1-yl]aniline

Details on test material:

- Name of test material (as cited in study report): p-Amino-Azobenzol (4-Aminoazobenzene)
- Analytical purity: > 98%

Sampling and analysis

Analytical monitoring:

no

Test solutions

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test substance was added in the required amount to the test vessel with about 180 ml deionized water. The mixture was stirred for about 22 ± 2 hours to obtain an optimal solution. Then synthetic medium (8 ml of a 100-fold stock) was added, the pH-value was adjusted to 7.5 ± 0,5, the inoculum was added and the test started.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: The activated sludge inoculum used in this study originated from laboratory wastewater treatment plants fed with municipal sewage. The inoculum was washed, brought to a concentration of 5 g/l dry substance and aerated for 24 hours. 50 ml were added to a total volume of 250 ml to obtain a concentration of 1 g/l dry substance in the test.
- Initial biomass concentration: 1000 mg/L

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

180 min

Test conditions

Test temperature:

20 °C

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer-vessel (nominal volume 250 ml)
- Type (delete if not applicable): open / closed
- Fill volume: 250 ml
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- No. of organisms per vessel:
- No. of vessels per concentration (replicates):
- No. of vessels per control (replicates):
- No. of vessels per vehicle control (replicates):
- Biomass loading rate:


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic medium according to OECD
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:


OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod:
- Light intensity:


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

180 min

Dose descriptor:

other: EC20

Effect conc.:

ca. 15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

180 min

Dose descriptor:

EC50

Effect conc.:

ca. 47 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 3

Duration:

180 min

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

EC20 = ca. 1.5 mg/l
EC50 = ca. 6.5 mg/l
EC80 = ca. 40 mg/l