1,1,1-trifluoroethane

Toxicity to microorganisms

Administrative data

Endpoint:

toxicity to microorganisms

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The reference substance, 1,1,1,2-tetrafluoroethane, is also a fluorinated gaseous, poorly soluble ethane and will have similar toxicity to 1,1,1-trifluoroethane.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1991

Reference 2

Reference Type:

publication

Title:

Biodegradation and toxicity of HFCs and HCFCs

Author:

Berends, AG, de Rooij, CG, Shin-ya S, Thompson, RS

Year:

1999

Bibliographic source:

Arch. Environ Toxicol 36: 146-151

Materials and methods

Principles of method if other than guideline:

Based on a method described by Bringman and Kuhn (ref 1) and modified by Slabbert (ref 2),
ref. 1 Bringman G and Kuhn, R (1980). Comparison of the toxicity thresholds of water pollutants to bacteria, algae and protozoa in the cell multiplication inhibition test. Water Research 14, 231-241.ref 2. Slabbert JL (1986). Improved bacterial growth test for rapid water toxicity screening. Bull. Environ Contam Toxicol 37 565-569.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Norflurane

EC Number:

212-377-0

EC Name:

Norflurane

Cas Number:

811-97-2

Molecular formula:

C2H2F4

IUPAC Name:

1,1,1,2-tetrafluoroethane

Details on test material:

The test material, 1,1,1,2-tetrafluoroethane is very similar to the 1,1,1-trifluoroethane. Both are fluorinated ethanes and gasses of low solubality and reactivity in water. However this material has a higher boiling point (-26.2 deg C) compared to HFC-143a (-47.4 deg C) and therefore gave more reliable results than would have been expected from a test with HFC-143a.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
IUPAC name 1,1,1,2-tetrafluoroethane; CAS number 811-97-2; EC number 212-377-0; Structure CF3CFH2; colorless gas, boiling point -26.2 deg C, Henry's Law constant 10220 Pa m3/mol; vapor pressure 570 kPa at 20 deg. C; solubality 720 mg/l For 1,1,1-trifluoroethane: structure CF3CH3; colorless gas; boiling point -47.4 deg C; Henry's Law constant 11.2 kPa m3/mol at 20 deg C; solubility 761 mg/l @ 25 deg C

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Aqueous samples were taken from the stock solution (70% saturated) and the test vessels to determine the concentration of the test substance. Samples were taken from each test substance and control blank at the start and finish of the 6 hour test period. Additional samples were taken from the two replicate test culture flasks at nominal 56%, at the start and finish of the test. At 65 and 64% nominal concentrations, the blanks were sampled during the test to determine the air/water partition of the test substance. All samples were taken via the septum port using a gas tight microlight syringe.

Test solutions

Vehicle:

no

Details on test solutions:

HFC-134a was bubbled at 250 ml/min, for 60 minutes through a sample of sterile deionized water (4200 ml) via a sintered glass diffuser to obtain a saturated solution of the gas. This was diluted to 70% saturated using sterile deionized water that had been saturated with oxygen from a pressurized tank. This was used as the stock solution for preparation of the test solutions. Three replicate flasks were prepared of each test substance treatment, containing 20 ml of nutrient solution plus the approximate quantities of the stock solution and deionized water to yield the nominal concentrations control (0), 5.6, 10, 18, 32, 56 64% saturation.

Test organisms

Test organisms (species):

other: Pseudomonas putida

Details on inoculum:

18-20 hours before the start of the test, 4 ml of the test medium concentrate was added to 46 ml of deionized water in a sterile conical flask. A loop of Pseudonomous putida stock culture was added to this growth medium solution and then incubated over night at 25 deg. C on an orbital shaker. After this period the cells were diluted by addition of fresh growth medium solution at 25 deg C to an optical density which gave an absorbance of 0.8 +/- 0.05 at 600 nm (4cm cells) on Uvikon 860 spectrophotometer. This was used as the test inoculum.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

6 h

Post exposure observation period:

none

Test conditions

Hardness:

deionized water

Test temperature:

25 deg C

pH:

not reported

Dissolved oxygen:

not reported

Salinity:

deionized water

Nominal and measured concentrations:

Results from replicate analysis: 83, 85, 84 mg/l initial; after 6 hours: 86, 86, and 92 mg/l
Test concentration: measured/nominal 87/110, 82/110, 84/200, 88/200, 220/360, 230/360, 400/640, 400/640, 640/1100, 620/1100, 740/1300, 720/1300. Average ratio: 60%

Details on test conditions:

Three replicate flasks were prepared for each test substance treatment containing 20 ml of nutrient solution plus the appropriate quantities of the 70 % saturated stock solution and deionized water to provide the nominal concentrations : control, 5.6, 10, 18, 32, 56, and 64% saturation. Vessels were sealed during incubation with a PTFE/rubber septum port. The total volume was 310 ml, the solution was 255 ml after inocculation. Vessels were incubated for 6-hours at 25 deg.C and the optical density was then measured at 600 nm.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

6 h

Dose descriptor:

EC0

Effect conc.:

> 730 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Details on results:

The mean optical density for all cultures and the control flasks was in the range of 0.637 to 0.666 demonstrating that there was no inhibition of growth.

Results with reference substance (positive control):

The test substance, 3,5-dichlorophenol, showed a 95% reduction in growth at a nominal concentration of 18 mg/l, indicating that the Pseudomonous putida culture was responding normally to this known toxicant.

Reported statistics and error estimates:

not reported

Any other information on results incl. tables

The bacterial growth inhibition of 1,1,1,2 -tetrafluoroethane was determined by measuring the toxicity of the substance to the bacterium Pseudomonous putida. The EC10 and EC50 values were found to be >730 mg/l based on the measured concentrations of test substance.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

positive control gave expected results

Conclusions:

The bacterial growth inhibition of 1,1,1,2 -tetrafluoroethane was determined by measuring the toxicity of the substance to the bacterium Pseudomonous putida. The EC10 and EC50 values were found to be >730 mg/l based on the measured concentrations of test substance. The positive control, 3,5-dichlorophenol showed a 95% reduction in growth demonstrating that the test was valid.

Executive summary:

The bacterial growth inhibition of 1,1,1,2 -tetrafluoroethane was determined by measuring the toxicity of the substance to the bacterium Pseudomonous putida. The 6 -hour EC10 and EC50 values were found to be >730 mg/l based on the measured concentrations of test substance. This was considered to be the maximum concentration that could be tested. There was no growth inhibition.