Trifluoroiodomethane

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Feb 10, 2000 to Mar 31, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Supplier: F-Tech, Inc.
- Purity:>99%
- Impurity: Trifluoromethane <1%
- Lot No. 990423

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: 1484mg/L, stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: does not react.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Returned sludge from sewage plant was collected.
- Storage conditions: Stored unde aerobic condition
- Water filtered: yes
- Type and size of filter used, if any: FIlter No. 2

Duration of test (contact time):

28 d

Initial conc.:

3.64 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Prepared the following stock solutions, using analytical grade reagents:
(a) Potassium dihydrogen orthophosphate, KH2PO4 8.5 g
Dipotassium hydrogen orthophosphate K2HPO4 21.75 g
Disodium hydrogen orthophosphate dihydrate, Na2HPO4.2H2O 33.40g
Ammonium chloride, NH4Cl 0.5g

Dissolve in water and make up to 1 litre. The pH of the solution should be 7.4.

(b) Calcium chloride, anhydraous, CaCl2 27.5g
or
Calcium chloride dihydrate, CaCl2.2H2O 36.40g
Dissolve in water and make up to 1 litre.

(c) Magnesium sulphate hyptahydrate, MgSO4.7H2O 22.50 g
Dissolve in water and make up to 1 litre.
(d) Iron(III) chloride hexahydrate, FeCl3.6H2O 0.25 g
Dissolve in water and make up to 1 litre.

Mix 1 ml of solutions (a),(b), (c) and (d) with water and make up to 1 litre.

- Solubilising agent (type and concentration if used):
The saturated solution of test substance was prepared by bubbling test substance into 50 ml water for 60 min.
The concentration of the test substance in saturated solution was 1484 mg/L.
Concentration of the test substance 3.6mg/L
- Test temperature: 20±1 °C
- pH adjusted: no
- Aeration of dilution water: No
- Continuous darkness: yes
- Other: Closed bottle

TEST SYSTEM
- Culturing apparatus: 102 ml culturing bottle
- Number of culture flasks/concentration: 12 (test sample), 4 (reference), 11 (blank)
- Test performed in closed vessels due to significant volatility of test substance: Yea
- Test performed in open system: For reference substance, aniline
- Analysis : Dissolved oxygen measurement: Titration: Winkler azide modification method.
- Other:

SAMPLING
- Sampling frequency: 7, 14,21 and 28 day

CONTROL AND BLANK SYSTEM
- Inoculum blank: 11

Reference substance:

aniline

Test performance:

Validity of this test was confirmed as follows;
1) The percentage degradation of the reference compound was 78% calculated by BOD after 14 days.
2) Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days.
3) The residual concentration of oxygen in the test tube did not fall below 0.5 mg/L.

Key result

Parameter:

% degradation (test mat. analysis)

Value:

>= 0 - <= 2

Sampling time:

28 d

Key result

Parameter:

other: % degradation (BOD)

Value:

>= 0 - <= 2

Sampling time:

28 d

Parameter:

other: % degradation (BOD)

Value:

0

Sampling time:

21 d

Parameter:

other: % degradation (BOD)

Value:

>= 0

Sampling time:

14 d

Parameter:

other: % degradation (BOD)

Value:

>= 1 - <= 2

Sampling time:

7 d

Details on results:

Recovery test and blank test for test substance
1) Recovery test
Water + test substance 97.0 % 99.2 % average 98.1 %
Sludge + test substance 96.1 % 99.4 % average 97.7 %

2) Blank test
Test substance peak was not observed with GC analysis in the blank test.

Results with reference substance:

Referenc substance: Aniline
Percentage biodegradation after 7 days 82 % 83% average 82%
Percentage biodegradation after 14 days 77 % 79% average 78%

Table 1-1 Calculation table for dissolved oxygen measurements (Closed Bottle Test)

Sample description	Time of incubation (After x day)
	0	7	14	21	28
Control blank	9.24	9.08	8.78	8.58	8.42
Control blank	9.26	9.12	8.84	8.68	8.54
Average (mb)	9.25	9.10	8.81	8.63	8.48
Sludge + test substance (mt1)	-	8.98	8.82	8.66	8.38
Sludge + test substance (mt2)	-	9.02	8.92	8.74	8.46
Sludge + sodium benzoate(mt1)	-	5.00	4.94	-	-
Sludge + sodium benzoate(mt2)		4.96	4.86	-	-

 

Table 1-2 Calculation table for the percentage biodegradation by BOD (Closed Bottle Test)

Sample description	After X day	C	D	E
Sludge + test substance   -1	7	0.12	2
-2	7	0.08	1	2
-3	14	0.00	0
-4	14	0.00	0	0
-5	21	0.00	0
-6	21	0.00	0	0
-7	28	0.10	2
-8	28	0.02	0	1
Sludge + sodium benzoate -1	7	4.10	82
-2	7	4.14	83	82
-3	14	3.87	77
-4	14	3.95	79	78

A: Concentration (mg/L)

   Test substance             3.64 (mg/L)

   Sodium benzoate         3.00 (mg/L)

B: TOD (mgO₂/L)

  TOD of test substance

    CF₃I + 10O₂= CO₂+ 3F + I

    10O₂/CF₃I = 319.99/195.91 = 1.63

    TOD = 3.64×1.63 = 5.95 (mgO₂/L)

  TOD of sodium benzoate

    C₇H₅NaO₂+ 7.5O₂= 7CO₂+ 2.5H₂O + 0.5Na₂O

    7.5O₂/C₇H₅NaO₂= 239.99/144.1 = 1.67

     TOD = 3.00×1.67 = 5.01 (mgO₂/L)

C: BOD after x days (mgO₂/L) = mb(x) – mt(x) (see table 1-1)

D: Percentage of biodegradation (%) = C/B×100

E: Average percentage of biodegradation (%)

 

Table 2 Calculation table for recovery rate by GC

Sample description	A	D	E	F
Standard solution 0.0576 mg/L	3367
Water + test substance – 1	2994	0.366	97.0
Water + test substance – 2	3063	0.374	99.2	98.1
Sludge + test substance – 1	2965	0.362	96.1
Sludge + test substance – 2	3067	0.375	99.4	97.7
Control blank	n.d.

 Amount of test substance added: 0.377 (mg)

A: Peak area (μV·sec)

B: Final volume: 70 (mL)

C: Ratio of portion used for analysis: 1/102

D: Recovery amount (mg)

    D = G×(A/A(Standard))×(B/C)/1000

E: Recovery rate (%)

    E = D/0.377 (mg)×100

F: Average recovery rate (%)

G: Concentration of standard solution: 0.0576 (mg/L)

 

Table 3 Calculation table for percentage biodegradation by GC

Sample description	A	E	F	G	H
Standard solution 0.0576mg/L	3248
Water + test substance   -1	2832	0.359	97
Water + test substance   -2	2922	0.370	100
Sludge + test substance  -1	2884	0.365	98	0
Sludge + test substance  -2	2817	0.365	96	2	1
Control blank	n.d.

   Amount of test substance added: 0.371 (mg)

A: Peak Area (μV·sec)

B: Final volume: 70(mL)

C: Ratio of portion used for analysis: 1/102

D: Recovery rate: 98.1 (%) (Water + test substance)

                97.7 (%) (Sludge + test substance)

E: Residual amount of test substance (mg)

   E = I×(A/A(standard))×(B/C)/(D/100)/1000

F: Percentage residue (%)

   F = E/0.371 (mg)×100

G: Percentage biodegradation (%)

     G = {(E(Water + test substance) – E(Sludge + test substance))/E(Water + test substance)}×100

H: Average percentage biodegradation (%)

I: Concentration of standard solution: 0.0576 (mg/L)

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under test condition, the test substance was not ready biodegradable.

Executive summary:

The screening of chemicals for ready biodegradability of the test substance was carried out with closed bottle method (OECD 301D). Under the test condition, the test substance was not ready biodegradable.

Description of key information

The substance is not readily biodegradable as observed in a biodegradation screening study according to OECD TG 301D

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The biodegradation potential of the substance in water was determined in a screening study according to OECD TG 301D (Closed Bottle Test) and in compliance with GLP criteria (Kurume Laboratory, 2001). In this study 3.64 mg/L test substance was inoculated with returned sludge (activated, non-adapted) from sewage plant for 28 days under aerobic conditions in the dark. After the 28-day incubation period, the cumulative percentages of biodegradation were calculated from both the oxygen depletion (biological oxygen demand; BOD) and from the decrease of test item concentrations. The observed biodegradation percentages did not exceed 2% in either of the two analysis methods. Based on these findings the substance is classified as not readily biodegradable.