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Environmental fate & pathways

Biodegradation in water: screening tests

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biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: High because a scientifically defensible or guideline method was used. Critical study for SIDS endpoint. Only study summary reviewed from secondary source.

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to guideline
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Constituent 2
Reference substance name:
Ethane, 2,2-dichloro-1,1,1-trifluoro-
Ethane, 2,2-dichloro-1,1,1-trifluoro-
Details on test material:
- Name of test material (as cited in study report): HCFC-123
- Analytical purity: not reported.
- Name of test material (as cited in study report): HCFC 123
- Molecular formula (if other than submission substance): same as submission
- Molecular weight (if other than submission substance): same as submission
- Smiles notation (if other than submission substance): same as submission
- InChl (if other than submission substance): same as submission
- Structural formula attached as image file (if other than submission substance): same as submissiong.
- Substance type: halogenated ethane
- Physical state: liquid
- Analytical purity: not reported
- Impurities (identity and concentrations): not reported
- Purity test date: not reported
- Lot/batch No.: BB305 D55A
- Expiration date of the lot/batch: not reported
- Stability under test conditions: stable
- Storage condition of test material: at room temperature in the dark

Study design

Oxygen conditions:
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
A sample of secondary effluent was collected on the day if the test from a trickling-filter plant at a sewage treatment works that treats predominantly domestic waste. It was maintained under aerobic conditions in the laboratory. Immediately before use it was vacuum-filtered through a Whatman's GFC filter paper and filtrate used as the inoculum for the test (1 drop filtrate/liter test medium)
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
dissolved oxygen concentrations were measured by means of a YSI dissolved oxygen meter fitted with a self stirring DO/temperature bottle probe
Details on study design:
A test concentration of 12.5 mg/L was incubated in closed vials inoculated with an activated sludge culture obtained from a municipal wastewater treatment facility. Dissolved oxygen concentrations of duplicate vials were measured at the start of the experiment and after 5, 15, and 28 days at 20ºC. The experimental design is summarised in table 1.
- The mineral salt medium with a composition in accordance to the test guidance was prepared with tap water previously softened and treated by reverse osmosis and subsequently distilled.
- Test temperature was maintained at 20°C for the test duration
- pH was measured after dissolved oxygen and temperature measurement
- pH adjusted: no
- Aeration of dilution water: no information available
- Suspended solids concentration: no information available
- Continuous darkness: yes

- Culturing apparatus: BOD bottles equipperd with a dissolved oxygen meter
- Number of culture flasks/concentration: 8 flask/group in the main test
- Method used to create aerobic conditions: not reported
- Measuring equipment: dissolved oxygen meter fitted with a self-stirring DO/temperature bottle probe
- Test performed in closed vessels due to significant volatility of test substance
- Details of trap for CO2 and volatile organics if used: not reported

- Sampling frequency: 0, 5, 15 and 28 days
- Sampling method:

- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: 2 independent assays were carried out to assess bacterial inhibition
- Other:
Reference substance
Reference substance:
benzoic acid, sodium salt
2 mg/l

Results and discussion

Preliminary study:
Bacterial inhibition
The biodegradation of sodium benzoate was not significantly influenced by the presence of HCFC 123 in both assays. No significant deviations were observed in measure temperature and pH during the test period and among the different samples
Test performance:
0, 19 and 24% HCFC 123 (12.5 mg/l) was biodegraded after 5, 15 and 28 days, respectively. No significant deviations were observed in measure temperature and pH during the test period and among the different samples
% Degradation
% degradation (O2 consumption)
ca. 24
Sampling time:
28 d
Details on results:
Not readily biodegradable.

BOD5 / COD results

Results with reference substance:
about 60% sodium benzoate was biodegraded after 5 days of incubation

Applicant's summary and conclusion

Interpretation of results:
other: not readily biodegradable
Not readily biodegradable.