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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 Jun 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
no

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test solutions were prepared focussing on the maximum availability of the test substance for the micro-organisms. Treatment including magnetic stirring, mixing or with ultrasonic waves could be applied to ensure maximum availability. The exact procedure for preparation was based on the available test substance information. The batch tested was a clear colourless gas at room temperature. Testing was performed as worse-case situation. 2,3,3,3-Tetrafluoroprop-l-ene (HFO-1234yf) was tested by sparging the test medium with the test item at a rate of ~ 25 mL/min for approximately 2% hours during the 3 hour contact time. The gas flow rate was assessed using a soap-bubble flow meter. Optimal contact between the test substance and test organisms was ensured applying continuous aeration and stirring.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Source: Municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands
- Method of cultivation:
- Preparation of inoculum for exposure: The sludge was coarsely sieved, washed and diluted with ISO-medium. A small amount of the sludge was weighed and dried overnight at ca. 105 °C to determine the amount of suspended solids (3.8 g/L of sludge, as used for the test). The pH was 7.8 on the day of testing. The batch of sludge was used one day after collection; therefore 50 mL of synthetic sewage feed was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.
- Pretreatment:
- Initial biomass concentration:

Study design

Test type:
static
Water media type:
freshwater
Total exposure duration:
3 h

Test conditions

Test temperature:
18.8 - 19.9 °C
pH:
7.9 - 8.0
Nominal and measured concentrations:
The test medium was sparged with 2,3,3,3-Tetrafluoroprop-l-ene (HFO-1234yf) at a rate of ~ 25 ml/min for approximately 2.5 hours during the 3 hour contact time.
Details on test conditions:
TEST SYSTEM
- Test vessel: glass bottles
- Material, size, headspace, fill volume: All glass, approximately 300 mL oxygen bottles and 1-litre test bottles
- Aeration: yes
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Medium: Adjusted ISO medium, formulated using RO-water (tap-water purified by reverse osmosis; GEON Waterbehandeling, Berkel-Enschot, The Netherlands)
- Synthetic sewage feed: 16 g peptone, 11 g meat extract, 3 g urea, 0.7 g NaCI, 0.4 g CaCI2 x 2H2O, 0.2 g MgSO4 x 7H2O, 2.8 g K2HPO4. Dissolved in Milli-Q water, made up to 1 litre and filtered. The pH was within 7.5 ± 0.5.

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Oxygen consumption of the inoculum
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol

Results and discussion

Effect concentrations
Duration:
3 h
Dose descriptor:
EC50
Remarks on result:
other: See "Any other information on results incl. tables"

Any other information on results incl. tables

The 3-hour EC50 of 2,3,3,3-Tetrafluoropropene exceeded the concentration prepared by sparing the substance at a rate of ~ 25 mL/min for approximately 2.5 hours during the 3 hour contact time.

Applicant's summary and conclusion