2,3,3,4,4-pentafluoro-5-methoxy-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]tetrahydrofuran

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.054 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.054 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: limit test, no effect at only loading rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: limit test, no effect at only loading rate

Conclusions:

Novec 7700 is estimated to have no effect on Pseudokirchneriella subcapitata at its limit of water solubility (OECD 201)

Executive summary:

Novec 7700 toxicity to algae is assessed by readacross from Novec 7800. Toxicity of Novec 7800 to algae was examined in a limit test on Pseudokirchneriella subcapitata under OECD 201 guidelines. A water-accomodated fraction was made at a loading rate of ca. 100 mg/L. Measured concentrations at the beginning and end of the test were 0.124 mg/L and 0.0301 mg/L, respectively, with a geometric mean concentration of 0.0537 mg/L. No biologically relevant effects were observed (growth rate or cell morphology). The EC50 based on measured concentration was >0.0537 mg/L, with an EL50 of >100 mg/L based on nominal loading rate. As a limit test, the NOEC and NOELR were not exactly defined but were at least 0.0537 mg/L and 100 mg/L, respectively. As explained in the justification for type of information, the structural difference between Novec 7700 and Novec 7800 is unlikely to lead to a difference in toxicity to algae.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 - 31 May 2007

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

Guideline revision 23 March 2006

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Lot No.of test material: Lot number 1

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature, darkness
- Stability under test conditions: Stable

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Dedicated vessels were set up to allow for destructive sampling at 24 and 48 hours. 100-mL volumes were drawn by syringe from the middle of the flask at these time points. Equal volumes from each growth flask were drawn and pooled for the 72-hour measurement.
- Sample storage conditions before analysis: Samples analyzed day of sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A water-soluble fraction was prepared at a loading rate of ca. 100 mg/L. After stirring 48 hours at 23 °C in a closed flask with minimal headspace, the suspension was allowed to settle for 2 hours and liquid drawn from the middle of the flask. The withdrawn liquid was divided into the test vessels. It is unclear whether the solution was allowed to rest 24 hrs before filling the test vessels.
- Controls: untreated test medium
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none, test solutions were clear and colorless at start of test

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: ATCC 22662
- Source (laboratory, culture collection): Stock purchased from American Type Culture Collection and propagated at testing lab for ca. 12 years,
- Age of inoculum (at test initiation): 3 days, culture was in exponential growth phase
- Method of cultivation: Same conditions (medium, etc.) as experiment

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

22.9 - 23.4 °C

pH:

7.9 - 9.6

Nominal and measured concentrations:

Limit test, negative control and loading rate of ca. 100 mg/L
Measured concentrations,

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterilized 500 mL Erlenmeyer flasks (closed) with 100 mL medium
- Aeration: Continuous shaking
- Initial cells density: 5000 cells/ml.
- Control end cells density: 34,000 cells/mL
- No. of vessels per concentration (replicates): Six
- No. of vessels per control (replicates): Six

GROWTH MEDIUM
- Standard medium used: yes, OECD medium
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: Fluorescent light with wavelength range 400-700 nm, 92-99 E/m²/s (LI-COR Model LI-250A irradiance meter)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Particle counter Beckman Coulter model Z1
- Other: Cell condition examined post-experiment with Olympus model BX41 microscope.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: none, limit test
- Justification for using less concentrations than requested by guideline: no toxicity seen in preliminary study with a saturated solution.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.054 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: limit test, no effect at only loading rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.054 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: limit test, no effect at only loading rate

Details on results:

- Exponential growth in the control (for algal test): Yes
- Observation of abnormalities (for algal test): Yes, no abnormalities found

- Other:
- Any stimulation of growth found in any treatment: Yes
- Effect concentrations exceeding solubility of substance in test medium: Yes

Results with reference substance (positive control):

A toxicity test of K2Cr2O7 with the test organisms was conducted 4 days prior to the current study to confirm the reproducibility of the test conditions. The 72-hour ErC50 of K2Cr2O7 was 0.900 mg/L. This value was within the normal range in this laboratory [mean ± SD: 0.891 ± 0.097 mg/L, (n=3)].

Reported statistics and error estimates:

A small effect (0.06 - 3.87% inhibition) was found among individual test samples (mean, 2.11%). This effect was statistically significant, but given the small size of the inhibition (see table 3), the inhibition was not considered biologically significant.

Table 2, Cell counts during the algae experiment

Measured concentration	Replicate	Cell count (x10,000 cell/ml)
		0 hr	24 hr	48 hr	72 hr
<0.00276 mg/L	1	0.500	2.01	9.17	31.3
(Control)	2	0.500	1.87	10.2	30.6
	3	0.500	1.71	8.22	33.4
	4	0.500	1.93	10.5	35.8
	5	0.500	1.95	11.4	35.7
	6	0.500	1.92	10.7	36.8
	Mean	0.500	1.90	10.0	34.0
	S.D.	0.500	0.103	1.14	2.56
0.0537 mg/L	1	0.500	1.97	9.20	31.1
	2	0.500	1.95	10.8	28.8
	3	0.500	1.74	8.77	31.3
	4	0.500	2.02	10.5	29.5
	5	0.500	1.83	10.8	33.8
	6	0.500	2.04	9.06	31.6
	Mean	0.5	1.92	9.85	31.0
	S.D.	0.5	0.117	0.943	1.76

Table 3, Section specific growth rates (/day) during the algae experiment

Measured concentration	Replicate	0-24 hr	24-48 hr	48-72 hr	0-72 hr	% inhibition
<0.00276 mg/L	1	1.39	1.52	1.23	1.38	─
(Control)	2	1.32	1.70	1.10	1.37	─
	3	1.23	1.57	1.40	1.40	─
	4	1.35	1.69	1.23	1.42	─
	5	1.36	1.77	1.14	1.42	─
	6	1.35	1.72	1.24	1.43	─
	Mean	1.33	1.66	1.22	1.41	1.40 (of means)
	S.D.	0.06	0.10	0.10	0.03	0.18 (of means)
	overall CV					16.9
0.0537 mg/L	1	1.37	1.54	1.22	1.38	2.02
	2	1.36	1.71	0.98	1.35	3.87
	3	1.25	1.62	1.27	1.38	1.85
	4	1.40	1.65	1.03	1.36	3.24
	5	1.30	1.78	1.14	1.40	0.0576
	6	1.41	1.49	1.25	1.38	1.63
	Mean	1.35	1.63	1.15	1.38	2.11
	S.D.	0.06	0.11	0.12	0.02	─

Validity criteria fulfilled:

yes

Remarks:

control growth rate >0.92/d (1.41/d), CV for average specific growth rate <7% (1.8%), CV for section growth rate <35% (16.9%)

Conclusions:

Novec 7800 has no effect on P. subcapitata at its limit of water solubility (OECD 201)

Executive summary:

Toxicity of Novec 7800 to algae was examined in a limit test on Pseudokirchneriella subcapitata under OECD 201 guidelines. A water-accomodated fraction was made at a loading rate of ca. 100 mg/L. Measured concentrations at the beginning and end of the test were 0.124 mg/L and 0.0301 mg/L, respectively, with a geometric mean concentration of 0.0537 mg/L. No biologically relevant effects were observed (growth rate or cell morphology). The EC50 based on measured concentration was >0.0537 mg/L, with an EL50 of >100 mg/L based on nominal loading rate. As a limit test, the NOEC and NOELR were not exactly defined but were at least 0.0537 mg/L and 100 mg/L, respectively.

The test was conducted according to an internationally accepted test guideline under GLP. Considerable test substance was lost during the experiment; however, as a volatile and insoluble material some losses are considered unavoidable. The study is deemed reliable with restriction and suitable for use in Risk Assessment, Classification & Labeling, and PBT Analysis.

Description of key information

Novec 7700 is estimated to have no effect on Pseudokirchneriella subcapitata at its limit of water solubility (OECD 201)

Additional information

Novec 7700 toxicity to algae is assessed by readacross from Novec 7800. Toxicity of Novec 7800 to Pseudokirchneriella was examined according to OECD 201 guidelines. Given a loading rate of 100 mg/L, the geometric mean measured concentration in the test medium was 0.0537 mg/L. No toxicity was observed. As explained in the Analog Reporting Format justifying the readacross, the structural difference between Novec 7700 and Novec 7800 is unlikely to lead to a difference in toxicity to algae.