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Diss Factsheets

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethyl difluoroacetate
EC Number:
207-223-4
EC Name:
Ethyl difluoroacetate
Cas Number:
454-31-9
Molecular formula:
C4H6F2O2
IUPAC Name:
ethyl 2,2-difluoroacetate
Details on test material:
- Name of test material (as cited in study report): Ethyl difluoroacetate
- Physical state: Liquid /colourless, clear
- Analytical purity: 99.9%
- Batch No.: 33244/106 A
- Storage condition of test material: Storage in a refrigerator; avoid temperatures >70 °C

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: 2.0 g of the test substance was added to about 800 mL of demineralized water and stirred at room temperature until the test substance was completely dissolved. The pH-value was measured adjusted to 7.1 with 1 M sodium hydroxide solution. Finally the stock solution was made up to 1 L with demineralized water. The stock solution appeared clear.

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Preparation of inoculum for exposure: The activated sludge suspension was washed 3 times with tap water and sieved with a fine woven mesh (mesh size about 1 mm). This suspension was adjusted to a concentration of 7.5 g/L dry weight and pre-aerated over night. After the pre-aeration the lost water of the suspension was replaced
- Initial biomass concentration: 1.5 g/L dry substance

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
180 min

Test conditions

Test temperature:
22± 2 °C
pH:
7.2 - 7.3
Nominal and measured concentrations:
Nominal test concentrations: 62.4, 125, 250, 500, 1000 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer-vessel (nominal volume 250 ml)
- Test volume: 250 ml
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- No. of vessels per reference substance concentration (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 8 mL/vessel 100-fold concentrated OECD medium

EFFECT PARAMETERS MEASURED: respiration rate after 180 min
Reference substance (positive control):
yes
Remarks:
3,5 dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
180 min
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
180 min
Dose descriptor:
other: EC20
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
180 min
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
180 min
Dose descriptor:
other: EC80
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
EC20 (180 min) = 1.0 mg/L
EC50 (180 min) = 7.0 mg/L
EC80 (180 min) = 47.8 mg/L

Applicant's summary and conclusion