1,1,1,3,3,3-hexafluoropropan-2-ol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 - 27 Jul 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

28 Jul 2011

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD 23 "Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures"

Version / remarks:

23 Sep 2000

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1,3,3,3-hexafluoropropan-2-ol

EC Number:

213-059-4

EC Name:

1,1,1,3,3,3-hexafluoropropan-2-ol

Cas Number:

920-66-1

Molecular formula:

C3H2F6O

IUPAC Name:

1,1,1,3,3,3-hexafluoropropan-2-ol

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Remarks:

gas chromatography

Details on sampling:

- Concentrations: All concentration levels at the start of exposure, after 24 and 48 h, and at the end of exposure.
- Sampling method: Two additional replicates were prepared for sampling and analytical chemistry at 24 and 48 h. At the start of exposure as well as after 24 and 48 h, samples (100 mL) were taken from the separate replicates prepared for analytics. At the end of the test, samples (90 mL) were directly taken from the test vessels.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Test item solutions were prepared by measuring volume and taking account of the density of the test item (1.62 g/mL). A 100 mg/L stock solution was prepared by adding 0.065 mL test item below the surface of 1053 mL medium.
- Differential loading: No. The final test solutions were prepared by diluting the stock solution with medium. For the 100 mg/L concentration level, the test vessels were filled with undiluted stock solution.
- Controls: Medium without test item
- Evidence of undissolved material: The test solutions of all exposure levels were colorless and clear.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green freshwater microalga
- Strain: ATCC 22662
- Source: American Type Culture Collection (supply date: 30 Jun 1995)
- Age of inoculum: The inoculum was a 3 d old pre-culture, prepared under the same conditions as the test.
- Method of cultivation: Passage cultured under sterile conditions in the laboratory of the testing facility.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22.5 - 23.0 °C

pH:

7.8 - 8.0 (test start)
9.0 - 9.9 (test end)

Nominal and measured concentrations:

Control, 1.00, 3.16, 10.0, 31.6, and 100 mg/L (nominal)
Control, 0.976, 3.06, 9.26, 30.4, and 97.2 mg/L (geometric mean measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterilized 500 mL Erlenmeyer flasks
- Type: Closed, without headspace in order to avoid volatilisation of the test item.
- Initial cell density: 0.5E+04 cells/mL
- Control end cells density: 32E+04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: Yes, OECD medium according to guideline

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Purified water
- Culture medium different from test medium: Culture medium same as test medium
- Intervals of water quality measurement: The pH was measured in a separate replicate at test start and in one test vessel of every test level at the end of the test. Incubation temperature and light intensity were measured at test start and then daily.

OTHER TEST CONDITIONS
- Light intensity: 88 - 91 µmol*m^-2*s^-1
- Other: Incubation with rotary shaking (approximately 100 rpm)

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: Determination of biomass at the start and then every 24 h with a particle counter (Coulter Z2, Beckman Coulter, Inc.)
- Other: Appearance of cells (biological microscope, BX41 Olympus Corp.)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.16
- Range finding study: Yes
- Test concentrations: 0.10, 1.00, 10.0, and 100 mg/L
- Results used to determine the conditions for the definitive study: Yes, from the results of the preliminary study, the definitive study was carried out with nominal test item concentrations ranging from 1.00 to 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 97.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control: Yes, the number of cells in the control increased by a factor of 60 or more by the end of the test.
- Observation of abnormalities: The condition of the cells in all exposure levels and in the control was normal.
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes. The value is within the normal range (mean ± S.D. = 1.0 ± 0.20 mg/L, n = 31).
- ErC50 (0-3 d): 1.3 mg/L
- Other: The algae growth inhibition test with the reference substance and test organism is periodically conducted by the test facility. The last test dates from 22 - 25 May 2017

Reported statistics and error estimates:

Bartlett's test was used to determine the homogeneity of variance of the data.
A one-way ANOVA and Dunnett's multiple comparison test were used to determine the significant difference between the control and the exposure levels.
Statistical analysis was performed in Excel (Microsoft).

Any other information on results incl. tables

VALIDITY CRITERIA

The test fulfills the validity criteria defined by the guideline (Table 1).

The pH of the control varied more than the range indicated in the guideline (not more than 1.5). However, it was decided that the increase of pH in the control was due to the limit of the algae growth and the absence of gas exchange between outside and inside of the test vessel due to the closed test system. All other environmental condictions (except pH) were within the suitable range. Therefore, it was concluded that this study complied with the test guidelines.

 

Table 1: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	The number of cells in the control increased by a factor of 60 or more by the end of the test.	Yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	The mean coefficient of variation for section-by-section specific growth rates in the controls was 23%.	Yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	The coefficient of variation of specific growth rates in replicate controls was 1.2% and therefore does not exceed 7%.	Yes

 

 ANALYTICAL RESULTS

The measured concentration of the test item in the test solutions were 0.998 – 102 mg/L (96.0 – 102% of nominal concentration) at the start of exposure, 1.00 – 98.5 mg/L (94.4 – 100% of nominal concentration) at 24 h, 0.956 – 94.8 mg/L (90.6 – 95.7% of nominal) at 48 h and 0.944 – 94.8 mg/L (89.9-94.8% of nominal concentration) at the end of exposure (Table 2). The measured concentrations of the test item were within ± 20% of the nominal concentration.

 

Table 2. Measured concentrations of test item in test solutions.

Nominal concentration [mg/L]	Measured concentration [mg/L] (percentage of measured concentration versus nominal concentration %)
	At the start	24 h	48 h	At the end	Geometric mean
Control	n.d.	n.d.	n.d.	n.d.	-
1.00	0.998 (99.8)	1.00 (100)	0.956 (95.6)	0.944 (94.4)	0.976 (97.6)
3.16	3.18 (101)	3.09 (97.8)	3.02 (95.7)	2.98 (94.2)	3.06 (96.9)
10.0	9.60 (96.0)	9.44 (94.4)	9.06 (90.6)	8.99 (89.9)	9.26 (92.6)
31.6	31.7 (100)	30.5 (96.6)	30.0 (95.0)	29.7 (93.9)	30.4 (96.2)
100	102 (102)	98.5 (98.5)	94.8 (94.8)	94.8 (94.8)	97.2 (97.2)

n.d.: < 0.247 mg/L

 

 

BIOLOGICAL RESULTS

 The algal growth rate in the 100 and 31.6 mg/L exposure levels were significantly higher compared to the control. Algae growth in the other exposure levels were almost the same as in the control (Table 3).

Table 3. Growth rate and growth inhibition rate.

Nominal concentration [mg/L]	No	Growth rate [0 – 3d]	Growth inhibition rate [%]
Control	A	1.41	-
	B	1.38	-
	C	1.38	-
	D	1.40	-
	E	1.41	-
	F	1.37	-
	Mean	1.39	-
	S.D.	0.0168	-
1.00	A	1.42	-2.2
	B	1.35	3.0
	C	1.38	0.70
	Mean	1.38	0.47
	S.D.	0.0362	2.6
3.16	A	1.37	1.5
	B	1.38	0.59
	C	1.36	2.1
	Mean	1.37	1.4
	S.D.	0.0108	0.78
10.0	A	1.40	-0.96
	B	1.42	-2.4
	C	1.45	-4.6
	Mean	1.43	-2.7
	S.D.	0.0255	1.8
31.6	A	1.45	-4.5
	B	1.47	-5.4
	C	1.47	-5.8
	Mean	1.46	-5.2
	S.D.	0.00875	0.63
100	A	1.48	-6.7
	B	1.51	-8.7
	C	1.47	-5.9
	Mean	1.49	-7.1
	S.D.	0.0202	1.4

                      

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to "Any other information on results incl. tables".