Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Activated sludge from laboratory wastewater plants treating municipal sewage
- Concentration of dry substance 1 g/L

PREPARATION OF INOCULUM
- Inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated for ca. 24 h
- 50 ml were added to total volume of 250 ml to obtain concentration of 1 g/L dry substance in the test
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
180 min
pH:
6.6 - 7.8
Dissolved oxygen:
7.2 - 8.7 mg O2/L
Nominal and measured concentrations:
Concentrations (mg/L): 1000, 500, 101, 50, 10 (nominal)
Details on test conditions:
TEST SYSTEM
- Test vessels: Erlenmeyer-vessel (nominal volume 250 ml)
- Test volume: 250 ml
- Synthetic medium: 8 ml/vessel 100-fold concentrated OECD medium
- Test substance was added in required amount to test vessel with about 180 ml deionized water; mixture was stirred for 22 +/- 2 h to obtain optimal solution; then, inoculum and synthetic medium was added and test started
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Key result
Duration:
180 min
Dose descriptor:
other: EC20
Effect conc.:
18 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Key result
Duration:
180 min
Dose descriptor:
EC50
Effect conc.:
50 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Duration:
180 min
Dose descriptor:
other: EC80
Effect conc.:
170 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Details on results:
OXYGEN MEASUREMENTS
- Oxygen consumption rate (mg O2/L*6 min): 0.2 - 2.2
- Oxygen consumption rate (mg O2/L*h): 2 - 22
- Change in oxygen consumption rate compared with blank control (%): 0 - 91
Results with reference substance (positive control):
EC VALUES
- 180 min EC50 4.5 mg/L nominal test mat.

OXYGEN MEASUREMENTS
- Oxygen consumption rate (mg O2/L*6 min): 0.2 - 1.7
- Oxygen consumption rate (mg O2/L*h): 2 - 17
- Change in oxygen consumption rate compared with blank control (%): 23 - 91
Validity criteria fulfilled:
yes
Conclusions:
For ´α,α'-propylenedinitrilodi-o-cresol´ the influence on the respiration of microorganisms was investigated in a GLP guideline study according to OECD 209. The study was conducted with activated sludge from laboratory wastewater plants treating municipal sewage.

After 3 hours of incubation the EC20 was 18 mg/L and EC50 = 50 mg/l based on nominal concentration.

Description of key information

The influence of the substance on the respiration of microorganisms was investigated in a GLP guideline study according to OECD 209. The study was conducted with activated sludge from laboratory wastewater plants treating municipal sewage.

After 3 hours of incubation, the EC20 was 18 mg/l and the EC50 was 50 mg/l basedon nominal concentration.

Key value for chemical safety assessment

EC50 for microorganisms:
50 mg/L
EC10 or NOEC for microorganisms:
18 mg/L

Additional information

Depending on local conditions and existing concentrations, disturbances in the biodegradation process of activated sludge are possible.

Categories Display