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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: screening tests
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed to GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report date:
2005

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: "Method for Testing the Biodegradability of Chemical Substances by Microorganisms" stipulated in "Testing Methods for New Chemical Substances" (November 21,2003; No. 1121002, Pharmaceutical and Food Safety Bureau, Ministry of Health, Labour and Welfare
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2,3,3-tetrafluorooxetane
EC Number:
700-202-5
Cas Number:
765-63-9
Molecular formula:
C3H2F4O
IUPAC Name:
2,2,3,3-tetrafluorooxetane
Details on test material:
- Name of test material (as cited in study report): 2,2,3,3-Tetrafluorooxetane
- Substance type:
- Physical state: Liquid
- Analytical purity: 99.0%
- Purity test date: No data
- Lot/batch No.: S4X01
- Expiration date of the lot/batch: Not reported
- Stability under test conditions: The test item was stable under the storage conditions, as shown by the finding that IR spectra of the test item before the experimental start and after the experimental completion were identical.
- Storage condition of test material: Cold and dark storage place.
- Other:

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
mixture of sewage, soil and natural water
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): On-site sludge sampling was carried out at the following ten locations in Japan:
Fushikogawa city sewage plant (Sapporo-shi, Hokkaido), Fukashiba industrial sewage plant (Kashima-gun, Ibaraki), Nakahama city sewage plant (Osaka-shi, Osaka), Ochiai city sewage plant (Shinjuku-ku, Tokyo), Kitakami River (Ishinomaki-shi, Miyagi), Shinano River (Niigata-shi, Niigata), Yoshino River (Tokushima-shi, Tokushima), Lake Biwa (Otsu-shi, Shiga), Hiroshima Bay (Hiroshima-shi, Hiroshima), Dokai Bay (Kitakyushu-shi, Fukuoka)
- Laboratory culture:
- Method of cultivation: After ceasing aeration of the sludge mixture for approximately 30 minutes, supernatant corresponding to about one third of the whole volume was removed. Dechlorinated water was added to the remaining portion so that the total volume reached 10 L. This mixture was aerated for 30 minutes or more, and then a pre determined amount of synthetic sewage was added to the mixture so that the concentration of the
synthetic sewage was 0.1% in the volume of dechlorinated water added. This procedure was repeated once every day.

Synthetic sewage: Glucose, peptone and potassium dihydrogenphosphate were dissolved in purified water to obtain 50 g/L of the solution for each component. The pH of the solution was adjusted to 7.0±1.0 with sodium hydroxide.
- Storage conditions:
- Storage length: 3 months
- Preparation of inoculum for exposure: The filtrate (5 L) of the supernatant of the activated sludge cultivated for about three months was mixed with the mixed filtrate (5 L) of the supernatant of a sludge newly collected at each sampling location. The mixed filtrate (10 L) was aerated after the pH
value of the mixture was adjusted to 7.0±1.0.
- Pretreatment:
- Concentration of sludge:
- Initial cell/biomass concentration:
- Water filtered: yes/no
- Type and size of filter used, if any:
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: Each 3 mL of solutions A, B, C and D, which are prescribed in JIS K 0102-1998 Section 21, were made up to 1000 mL with purified water (Japanese Pharmacopeia, Takasugi Pharmaceutical Co., Ltd.), and then the pH of this solution was adjusted to 7.0.
- Additional substrate:
- Solubilising agent (type and concentration if used):
- Test temperature: 25±1°C
- pH: 7.0±1.0
- pH adjusted: yes
- CEC (meq/100 g):
- Aeration of dilution water: Stirred with magnetic stirrer
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes
- Other:


TEST SYSTEM
- Culturing apparatus: Vessel 300 mL in volume (Improved type for volatile substance)
- Number of culture flasks/concentration: 4 (3 with sludge + test item, 1 with water + test item)
- Method used to create aerobic conditions: Mixtures stirred
- Measuring equipment: Closed system oxygen consumption measuring apparatus
(Temperature controlled bath and measuring unit : Ohkura Electric Co., Ltd.)
(Data sampler: Asahi Techneion Co., Ltd.)
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Details of trap for CO2: Soda lime
- Other:


SAMPLING
- Sampling frequency: For Biochemical oxygen demand, not stated.
- Sampling method: The change in BOD of the test solutions was measured by autorecording using a data sampler.
- Sterility check if applicable: No
- Sample storage before analysis: Cooled in refrigerator for 22 hrs before analysis for total organic carbon, dissolved organic carbon, GC analysis of TFO and analysis for fluoride ions.
- Other:


CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: Yes
- Toxicity control: No
- Other:


STATISTICAL METHODS:
Reference substance
Reference substance:
aniline

Results and discussion

Test performance:
Although the test item was not detected, approximately theoretical amount of DOC (dissolved organic carbon) was detected in all the test solutions. Therefore, DHA (2,2-difluoro-3-hydroxy-propionic acid, one of the expected converted products) was determined. As a result, 97% of the theoretical amount of DHA was detected (including percentage detection of DHA in soda lime). It was considered that the test item was hydrolyzed completely and converted into DHA. In addition, 45-49% of the theoretical amount of fluoride ion was detected. This result suggested that two of four fluorine atoms were desorbed from the test item when the test item was converted into DHA. The mass balance, which was calculated by the sum of the percentage residue of the test item and the percentage production (detection) of DHA, was as good as 97%. No peak corresponding to converted products except for DHA and fluoride ion was detected on the GC and HPLC chromatograms. It was considered that any converted products except for DHA and fluoride ion were not produced. From the above-mentioned results and the percentage biodegradation by BOD (0%), it was considered that DHA and fluoride ion were not biodegraded by microorganisms under the test conditions of this study.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Remarks on result:
other: Reduction due to hydrolysis not biodegradation

BOD5 / COD results

BOD5 / COD
Parameter:
BOD5
Results with reference substance:
Results with reference substance were valid, % biodegradation of aniline was 84% after 14 days under the test conditions. (Criterion for validity is >=60%.)

Any other information on results incl. tables

Table 1 gives the calculated biochemical oxygen demand (BOD) results for each of 6 vessels at 4 time points from day 7 to day 28. Vessel 1: Water + test item, Vessels 2,3,4: Sludge + test item, Vessel 5: Control blank, Vessel 6 sludge + aniline

Table-l Calculation table for percentage biodegradation by BOD

Vessel No.

Day 7

Day 14

Day 21

Day 28

Mean degradation

 

BOD (mg)

Deg. (%)

BOD (mg)

Deg. (%)

BOD (mg)

Deg. (%)

BOD (mg)

Deg. (%)

 

6

64.0

69

80.0

84

87.5

90

92.2

91

 

5

2.1

-

4.1

-

6.2

-

10.0

-

 

2

2.0

0

2.6

0

3.0

0

5.5

0

0

3

2.0

0

2.7

0

3.1

0

6.1

0

 

4

2.0

0

2.6

0

2.8

0

5.7

0

 

1

0.3

-

0.6

-

0.6

-

2.9

-

 

Applicant's summary and conclusion

Validity criteria fulfilled:
no
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item was hydrolyzed completely and converted into 2,2-difluoro-3-hydroxy-propionic acid and fluoride ion under the test condition of this study. 2,2-Difluoro-3-hydroxy-propionic acid and fluoride ion were not biodegraded by
microorganisms.

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