1,1,1,3,3,3-hexafluoro-2-methoxypropane

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 January 2019 thru 1 February 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Remarks:

Extra care taken to minimize volatilization losses

GLP compliance:

yes

Specific details on test material used for the study:

Reference ID: Propane, 1, 1, 1, 3, 3, 3-hexafluoro-2-methoxy- / CAS No. 13171-18-1
Label ID: 1,1,1,3,3,3,-HEXAFLUORO-2-METHOXYPROPANE-CAS NO.: 13171-18-1
LOT #: 17004
Date & Qty. Received: 06 Nov 18; 65.1 g (GW)
Physical Description: Clear liquid
Storage: Room temperature

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 and 100 mg/L

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

Method: The limit stock solution was prepared by dissolving 370 µL of test substance in 1000 mL of OECD medium and mixing for 15 minutes. This prepared a 200 mg/L solution as the concentration was double the desired final concentration until media containing algae cells was added in equal volume to prepare the 100 mg/L test concentration.

Controls: . A test substance control solution was made using only dilution water. A positive control solution was prepared using zinc chloride (Mfg: Acros, Lot: A037487, Exp: 27 Feb 2022).
Chemical name of vehicle (organic solvent, emulsifier or dispersant): Not applicable
Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): Not applicable
Evidence of undissolved material (e.g. precipitate, surface film, etc.): None

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum)
- Source (laboratory, culture collection): STILLMEADOW, Inc. cultures
- Age of inoculum (at test initiation): 3 - 7 days
-
CULTIVATION METHOD: Pseudokirchneriella subcapitata parent and daughter cultures are continuously maintained at STILLMEADOW, Inc. Prior to testing, 1000 mL of autoclaved OECD medium was inoculated with 5-day old organisms. This new mass culture was then placed in a 24°C environmental chamber. Autoclaved media had a pH of 8.1 ±0.1; therefore, no adjustment to pH was needed. All procedures were conducted aseptically

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

None

Test temperature:

23 - 26 deg C

pH:

7.4 - 9.5

Nominal and measured concentrations:

Nominal: 100 mg/L. To account for volatilization losses during preparation and sampling of solutions, nominal dose concentrations were calculated based on an active of 40% concentration and a density of 1.38 g/mL.
Measured (at start): 129.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL sterile Erlenmeyer flasks with foam stoppers; filled with 100 mL of the appropriate solution
- Type (delete if not applicable): closed
- Headspace: Minimized due to the substance being highly volatile from water
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): Not applicable.
- Renewal rate of test solution (frequency/flow rate): Not applicable.
- Initial cells density: 10000 cells/mL
- No. of organisms per vessel: Not applicable.
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 6 (negative); 3 (positive)
- No. of vessels per vehicle control (replicates): Not applicable.

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: Not applicable.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 4300 lux
- Salinity (for marine algae): Not applicable.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: hemocytometer
- Chlorophyll measurement: Not applicable.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not applicable.
- Justification for using less concentrations than requested by guideline: Not applicable.
- Range finding study: Yes, resulting in decision to conduct limit test.
- Test concentrations: 1, 5, 10, 50, 100 mg/L.
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Remarks:

Zinc chloride

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 129.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Unusual cell shape: no
- Colour differences: no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? Yes

Reported statistics and error estimates:

The NOEC and EC50 were determined by a commercially available statistical program (ToxCalc Version 5.0™). Linear Interpolation was used for EC50 determination.

Limit Test Average Growth Rate Results:

Concentration (mg/L)*	Rep	Cell Density x 10^4cells/mL			Initial pH	Terminal pH	Avg. Growth Rate
		24 hours	48 hours	72 hours
Control	A	12	28	99	8.1	8.3	0.064
	B	13	33	110		8.3	0.065
	C	11	28	97		8.5	0.064
	D	10	25	32		7.4	NA
	E	10	23	107		8.3	0.065
	F	10	19	28		7.4	NA
129.8	A	10	11	93	8.1	9.5	0.063
	B	9	25	96		9.3	0.063
	C	8	6	21		8.2	NA
	D	8	27	101		9.5	0.064
Positive Control (10 mg/L)	A	0	1	0	7.0	7.7	0
	B	1	1	1		7.7	0
	C	1	0	0		7.6	0

*Measured.

Validity criteria fulfilled:

yes

Conclusions:

The 72-hour EC50 for Pseudokirchneriella subcapitata (Green algae) is >129.8 mg/L.

Executive summary:

In a GLP guideline study conducted according to OECD Method 201, green algae (Pseudokirchneriella subcapitata) were exposed to the test substance under static conditions in tightly sealed containers at a nominal limit dose concentration of 100 mg/L (measured concentrations at time zero was 129.8 mg/L). No inhibition of growth was observed. Based on these results, the 72 -hour EC50 is >129.8 mg/L and can be considered to not pose a danger in the aquatic environment.

Description of key information

In a GLP guideline study conducted according to OECD Method 201, green algae (Pseudokirchneriella subcapitata) were exposed to the test substance under static conditions in tightly sealed containers at a nominal limit dose concentration of 100 mg/L (measured concentrations at time zero was 129.8 mg/L). No inhibition of growth was observed. Based on these results, the 72 -hour EC50 is >129.8 mg/L and can be considered to not pose a danger in the aquatic environment.