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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 April 2017 - 14 September 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP compliant
Cross-reference
Reason / purpose:
reference to other study
Reference
Endpoint:
bulk density
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 September 2016 - 11 January 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP compliant
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 109 (Density of Liquids and Solids)
Version / remarks:
02 October 2012
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.3 (Relative Density)
Version / remarks:
31 May 2008
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 830.7300 (Density / Relative Density / Bulk Density)
Version / remarks:
June 2002
Deviations:
no
GLP compliance:
yes
Type of method:
pycnometer method
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL:
- At room temperature

OTHER SPECIFICS:
- Purity/composition correction factor: No correction factor required.
- Test item hanling: No specific handling conditions required, but for practical reason the test item could be kept on ice to avoid evaporation of the material before and between performance of physico-chemical tests.
Key result
Type:
bulk density
Density:
1.23 g/cm³
Temp.:
6 °C
Conclusions:
The density of 1,1,1-trifluoroacetone at 6ºC ± 1°C was 1.23 g/cm3.
Executive summary:

Measurement of the density of 1,1,1 -trifluoroacetone was performed using a volumetric flask according to standardised guidelines (OECD TG 109, EU A.3 and OPPTS 830.7300) under GLP conditions.

The test item is a volatile liquid with a boiling temperature of 20.5°C. It was observed that te density of the test item could not be experimentally determined at 20°C due to significant evaporation (gas bubbles) at about 19°C. The density of the test item was determined at a lower constant temperature of about 6°C.

The density of 1,1,1-trifluoroacetone at 6ºC ± 1°C was 1.23 g/cm3.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)
Version / remarks:
Adopted March 23, 2006, corrected 26 September 2014
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Inspection dates: 7 - 11, 14 and 16 September 2015. Date of the certificate: 03 November 2015.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
- Appearence: clear colourless liquid
- Test item storage: in refrigerator (2-8°C)

For further details, see section "confidential details on test material"
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Appearence: clear colourless liquid
- Test item storage: in refrigerator (2-8°C)

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: activated sludge freshly obtained from a municipal sewage treatment plant receiving predominantly domestic sewage [Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands]
- Storage conditions: kept under continuous aeration [synthetic air (CO2< 1 ppm): mixture of oxygen (ca. 20%) and nitrogen (ca. 80%)]
- Preparation of inoculum for exposure: before use, the sludge was allowed to settle (35 minutes) and the liquid was decanted for use as inoculum at the amount of 10 mL/L of mineral medium
- Concentration of sludge: 3.9 g/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
62.3 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
inorg. C analysis
Details on study design:
TEST CONDITIONS
- Composition of medium: 1 litre mineral medium contains: 10 mL of solution (A), 1 mL of solutions (B) to (D) and Milli-RO water.
*A) 8.50 g KH2PO4, 21.75 g K2HPO4, 67.20 g Na2HPO4.12H2O and 0.50 g NH4Cl dissolved in Milli-Q water made up to 1 litre, pH 7.4+/-0.2
*B) 22.50 g MgSO4.7H2O dissolved in Milli-Q water and made up to 1 litre
*C) 36.40 g CaCl2.2H2O dissolved in Milli-Q water and made up to 1 litre
*D) 0.25 g FeCl3.6H2O dissolved in Milli-Q water and made up to 1 litre
- Test temperature: 20.0 to 21.7 °C
- pH: 7.5 to 7.9
- Suspended solids concentration: 3.9 g/L
- Continuous darkness: yes with a shaking rate sufficient to keep the vessels well mixed and in suspension
- Other: Since 1,1,1-trifluoroacetone was volatile, aliquots of 5.6 µL were added directly to each vessel by injection through the septum, using a glass Hamilton GC syringe, corresponding with 6.7 mg test item/vessel of 107 mL.

TEST SYSTEM
- Number of culture vessels: Five test vessels for analysis at the end of the test and triplicate test vessels for other time intervals for each treatment.
- Measuring equipment: a Shimadzu TOC-VCPH total organic carbon analyzer combined with a Shimadzu ASI-V autosampler
- Test performed in closed vessels due to significant volatility of test substance: Well sealed glass serum vessels
- Other: Pretreatment: 1 mL 7 M NaOH was injected through the septum of each vessel and the vessels were returned to the orbital shaker for 1 h. Thereafter, the vessels were removed from the shaker and allowed to settle. The supernatant was used for IC analysis.

SAMPLING
- Sampling frequency: Inoculum blank and test item: day 1, 7, 14, 23 and 28 / Procedure control and toxicity control: day 1, 7 and 14 / Abiotic control: day 1 and 28. Each sample was analyzed at least in triplicate.

CONTROL AND BLANK SYSTEM
- Inoculum blank: containing inoculated medium
- Procedure control: containing inoculated medium and reference item.
- Test item: containing inoculated medium and test item.
- Toxicity control: containing inoculated medium, reference item and test item.
- Abiotic control: containing untreated medium, test item and sterilising agent.

STATISTICAL METHODS: None
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Key result
Parameter:
% degradation (inorg. C analysis)
Value:
0
Sampling time:
28 d
Details on results:
The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of 1,1,1-trifluoroacetone.
In the toxicity control more than 25% biodegradation occurred within 14 days (37%, based on ThCO2). Curves of biodegradation of 1,1,1-trifluoroacetone and reference item are profided in section "Illustration (picture/graph)".
Therefore, the test item was assumed not to inhibit microbial activity.

BOD5 / COD results

Results with reference substance:
With the reference substance (benzoic acid, sodium salt), 77% biodegradation occurred within 14 days.

Any other information on results incl. tables

Degradation in Percentage of the Theoretical Maximum IC Production (ThIC)

    Nominal day Microbial degradation in percentage of the ThIC        Degradation 
Reference Item  Test Item Toxicity Control  Abiotic Control 
-2 
78  37  n.a. 
14  77  37  n.a. 
23  n.a.  n.a.  n.a. 
28  n.a.  n.a.  -5 

n.a.: Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test substance, 1,1,1-trifluoroacetone, was not readily biodegradable under the conditions of the Headspace Test performed.
Executive summary:

Evaluation of the readily biodegradability of 1,1,1-trifluoroacetone was performed in an aerobic, aqueous inoculated medium (Headspace Test) according to standardised guidelines (OECD TG 310) under GLP conditions.

The test item was added to the mineral medium to give a final organic carbon concentration of 20 mg C/L, corresponding with 62.3 mg test item/L. Since 1,1,1-trifluoroacetone was volatile, aliquots of 5.6 µL were added directly to each vessel by injection through the septum, using a glass Hamilton GC syringe, corresponding with 6.7 mg test item/vessel of 107 mL.

The test consisted of five groups:

1. Test item: vessels each containing 1,1,1-trifluoroacetone (CAS NR : 421-50-1) at 20 mg C/L,

2. Toxicity control: vessels each containing 1,1,1-trifluoroacetone (CAS NR : 421-50-1) at 20 mg C/L and reference item at 20 mg C/L,

3. Positive control: vessels each containing reference item at 20 mg C/L,

4. Blank control: vessels containing untreated mineral medium.

5. Abiotic control: vessels containing 1,1,1-trifluoroacetone (CAS NR : 421-50-1) at 20 mg C/L and mineral medium treated with sterilizing agent.

The CO2 evolution resulting from the aerobic biodegradation of the test item was determined by measuring the inorganic carbon (IC) produced in the test vessels in excess of that produced in blank vessels containing inoculated medium only. Biodegradation was expressed as a percentage of the theoretical maximum IC production, based on the quantity of test item (as C) initially added.

The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of 1,1,1-trifluoroacetone (CAS NR : 421-50-1). Since all criteria for acceptability of the test were met, this study was considered to be valid.

Therefore, under the conditions of the Headspace Test, 1,1,1 -trifluoroacetone was not readily biodegradable.