Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
other information
Study period:
April 28, 1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented and reported study, conducted equivalent to internationally accepted technical guideline in recognized research organization.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
, 1984
Deviations:
yes
Remarks:
: instead of a centrifuged sludge a settled sludge was used. Due to the poor solubility of the test substance at test concnetrations, no stock solution was prepared. The test substance was given directly into the medium. Therefore, a constant factor betw
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Identification Code (as cited in study report) : PBS 2354.0
Generic/Trade name : Iminodibenzyl dest.
Batch No.: P. 4/92
Appearance: yellow solid
Purity : 97.1 %
Solubility (in water): < 2 mg/l (20°C)
Received : 08/04/93
Storage : room temperature
Stability : 12/93

Sampling and analysis

Analytical monitoring:
not required

Test solutions

Vehicle:
no
Details on test solutions:
20.9, 8.4, 4.0, 1.3, 0.6 and 0.4 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 ml with dechlorinated drinking water.

Test organisms

Test organisms (species):
activated sludge
Details on inoculum:
- Source of inoculum/activated sludge: Activated sludge collected from the sewage treatment plant of CH-4153 Reinach on 27/04/93. The pH after collection was 7.2.
- Preparation of inoculum for exposure: The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation. The pH of the sludge before use was 8.0.
- Initial biomass concentration: no data

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h

Test conditions

Hardness:
no data
Test temperature:
20 ± 2 °C
pH:
8.4 - 8.6
Dissolved oxygen:
no data
Salinity:
not applicable (freshwater)
Nominal and measured concentrations:
nominal 104.5, 42.0, 20.0, 6.5, 3.0, 2.0 and 0 (blank) mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 ml BOD flasks with gas inlet
- Aeration: yes
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Biomass loading rate: 1.57 g/l (dry weight

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated drinking-water
- Intervals of water quality measurement: The pH was measured after 3h aeration.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : respiration inhibition after 3-hour aeration

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5 - 3.1. Due to the poor solubility of the test substance at test concentrations, no stock solution was prepared. The test substance was given directly into the medium. Therefore, a constant factor between the test concentrations could not been achieved.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol; 32.0, 10.0 and 3.2 mg/l

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
other: EC20
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
other: EC80
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
Oxygen consumption rates were 47.8 and 49.6 mg/l/h for the controls and 46.1-49.6 mg/l/h for the test substance.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC50 (3h) = 18.4 mg/l (accepted range: 5-30 mg/L)
Reported statistics and error estimates:
The Results ( ECxx Values ) were calculated with linear regression.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Criteria of OECD Guideline 209: The difference between the controls was within 15% of each other. The EC50 of 3,5-dichlorophenol was in the accepted range of 5-30 mg/l.
Executive summary:

In a 3-h toxicity study activated sludge from a sewage treatment plant was exposed to PBS 2354.0 in accordance with OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test). The study was performed in compliance with GLP. Reliability grade 1 was assigned. Tested concentrations were 0 (controls), 2.0, 3.0, 6.5, 20.0, 42.0, and 104.5 mg/l. PBS 2354.0 was not toxic to waste water (activated sludge) bacteria up to and including a nominal concentration of 104.5 mg/l. Thus, the 3h-EC20, -EC50 and -EC90 was above 100 mg/L.