Registration Dossier

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:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
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 concentrationsopen allclose all
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
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
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

Applicant's summary and conclusion