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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
September 19, 2017 to December 14, 2017
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 (Carbon and Ammonium Oxidation))
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Name (as stated in the report): Silvial
Batch No.: SC00021294
Expiration date: March 25, 2018
Purity: 99.7%
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Activated sludge was obtained from a water treatment plant treating predominantly domestic sewage (Bois-de Bay, 1242 Satigny, Switzerland). The sludge was kept aerobic until being used on the next day. The pH was 7.5.
The suspended solids content was determined by drying 50 ml of the sludge and weighing: dry weight of suspended solids: 3.04 g/l.
A dilution to obtain a concentration of suspended solids of 3.0 g/l was not necessary. With the final dilution during the test, a concentration (i.e. in the range 0.8 to 1.6 g/l as recommended in ISO 8192-1986) was obtained.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
pH:
20 ± 2°C
Nominal and measured concentrations:
100 mg/L nominal concentration
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol was used as a reference substance to check the activity of the sludge: its EC50 (3 hours) should be within the range 2 to 25 mg/l.
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition
Validity criteria fulfilled:
yes
Conclusions:
At the tested concentration (100 mg/l) no significant inhibition was observed.
Therefore :
EC50(3 hours) of Silvial > 100 mg/l;
EC10(3 hours) of Silvial > 100 mg/l;
NOEC (3 hours) of Silvial = 100 mg/l;
Executive summary:

An activated sludge respiration inhibition test was performed with Silvial. In a limit test a test concentration of 100 mg/l was tested.

At the tested concentration (100 mg/l) no significant inhibition was observed.

Therefore :

EC50(3 hours) of Silvial > 100 mg/l;

EC10(3 hours) of Silvial > 100 mg/l;

NOEC (3 hours) of Silvial = 100 mg/l;

 

Description of key information

An activated sludge respiration inhibition test with Silvial (Study No. 16-E213, GLP) dated on December 14, 2017 was performed according to the OECD Guideline No. 209. At the tested concentration (100 mg/l) no significant inhibition was observed.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
100 mg/L

Additional information