Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well performed OECD study with GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
not specified
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
Test concentrations: 100, 180, 320, 580, 1000 mg/L.. Suspended by ultrasonic

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Source:domestic waste water treatment plant of Hildesheim
Pre-treatment: after sedimentation two times washing with dechlorinated water
nutrient solution: synthetic waste water according to OECD 209
dry-weight of the sludge: 2.44 g/L
not adapted activated sludge

Study design

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

Test conditions

Test temperature:
18 - 22 °C
Reference substance (positive control):
yes
Remarks:
Copper(II)sulfate-pentahydrate

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
other: EC20
Effect conc.:
280 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:
EC50
Effect conc.:
375 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: 228 mg/L < EC50 < 607 mg/L
Duration:
3 h
Dose descriptor:
other: EC80
Effect conc.:
500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
Conentration Respiration Rate inhibition
[mg/L] [mg O2/l x h) [%]
test substance 1000 0 100
test substance 580 10.2 68
test substance 320 16.4 48
test substance 180 31.2 1
test substance 100 33.2 - 5
reference 100 16.0 49
reference 180 6.8 79
reference 58 24.8 22
Results with reference substance (positive control):
see above

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The EC50 for toxicity to bacteria was determined as 375 mg/L (228 mg/L < EC50 < 607 mg/L)
Executive summary:

The toxicity to bacteria was tested according to OECD guideline 209 in a respiration inhibition test using not adapted activated sludge from a domestic waste water treatment plant. 5 concentrations were tested (1000, 580, 320, 180 and 100 mg/L) for three hours.

As reference substance (positive control) copper(II)sulphate-heptahydrate was used.

The results were integrated in a graphic and the EC-values were taken from that.

EC20: 280 mg/L

EC50: 375 mg/L (228 mg/L<EC50<607 mg/L)

EC80: 500 mg/L