Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1996-05-09 to 1996-06-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed acc. to Guideline, is well documented and run under GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Concentration of stock solution: 20000 mg/L
Preparation of stock solution:
20000mg of test substance was weighed in together with 800mL water.
Solution was stirred for 5 min. twice at 19°C
Afterwards it was treated 15min. twice by ultrasound
The pH was adjusted from 4.3 to 7.5 by using 10mol/L NaOH-solution.
The solution was then treated with ultrasound (15min) and was stirred (5min).
The test substance was only partially solublized. It was then filtrated and brought up to 1L.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Activated sludge was used.
source: municipal waste treatment plant Frankfurt/Sindlingen
Treatment: According to the guideline. The bacterial culture was adapted neither to the test substance nor to the reference substance before the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
Remarks on exposure duration:
The exposure period was reduced to 30 Min because of the volatility of the test substance. Results are related to the analytical measurements.

Test conditions

Test temperature:
19.7 - 20.3°C
pH:
7.3 - 7.4
Nominal and measured concentrations:
Test was run in duplicates. Measured test concentrations were 5.0, 10.2, 26.5, 37.2, 47., 84.7, 218.6 and 593.0
Details on test conditions:
Because of the high volatility of the test substance in aqueous solution, the incubation period was shortened to 30 minutes. Initially and after each test at the end the test substance content was determined via the dissolved organic carbon (DOC). Based on the analytical results the stability of the test concentrations cannot be guaranteed over the test time. At some concentration levels, a significant decrease (> 20%) of the test substance during the test period was found. Therefore, all concentration data refer to the values ​​which were analytically determined directly after recording the activity curves.
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorphenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
30 min
Dose descriptor:
other: EC20
Effect conc.:
36 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks on result:
other: confidence interval 15 - 67 mg/L
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
337 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks on result:
other: confidence interval 162 - 1597 mg/L
Duration:
30 min
Dose descriptor:
other: EC80
Effect conc.:
> 555 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The calculated EC50 is 360 mg/L wiith a confidence intervall of 173-1706 mg/L.