3,3,4,4,4-pentafluorobut-1-ene

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:

21/03/2018 - 21/04/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,3,4,4,4-pentafluorobut-1-ene

EC Number:

206-775-3

EC Name:

3,3,4,4,4-pentafluorobut-1-ene

Cas Number:

374-27-6

Molecular formula:

C4H3F5

IUPAC Name:

3,3,4,4,4-pentafluorobut-1-ene

Test material form:

gas

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples of the algal populations were removed daily.

Test solutions

Details on test solutions:

A saturated solution was prepared by bubbling the test item at approximately 40 mL/minute for approximately 15 minutes through 11 liters of culture medium whilst stirring using a magnetic stirrer to give a 100% v/v saturated solution. A series of dilutions was made from this saturated solution to give further stock solutions of 32, 10, 3.2 and 1.0% v/v saturated solution. An aliquot (900 mL) of each of the stock solutions was separately inoculated with 4.7mL of algal suspension to give the required test concentrations of 1.0, 3.2, 10, 32 and 100% v/v saturated solution.
The stock solutions and each of the prepared concentrations were inverted several times to ensure adequate mixing and homogeneity.
The concentration and stability of the test item in the test preparations were verified by chemical analysis at 0 and 72 hours

Test organisms

Test organisms (species):

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

Details on test organisms:

The test was carried out using Pseudokirchneriella subcapitata strain CCAP 278/4. Liquid cultures of Pseudokirchneriella subcapitata were obtained from the Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd, Scottish Marine Institute, Oban, Argyll, Scotland. Master cultures were maintained in the laboratory by the periodic replenishment of culture medium (Section 3.3). The master cultures were kept under constant agitation by orbital shaker (approximately 150 rpm) and constant illumination at 24 ±1 °C.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Post exposure observation period:

All test and control cultures were inspected microscopically at 72 hours. There were no abnormalities detected in any of the control or test cultures.

Test conditions

Test temperature:

Temperature was maintained at 24 ±1 ºC throughout the test.

pH:

The pH value of the control cultures was observed to increase from pH 7.7 at 0 hours to pH 10.1 at 72 hours. This increase was considered to be due to the amount of carbon dioxide required by the large number of algal cells in the log phase of growth exceeding the transfer rate of CO2 from the gaseous phase to the aqueous phase. In this situation CO2 required for photosynthesis and growth would be derived from bicarbonate in solution which results in an increase in the pH of the culture. The increase in pH after 72 hours was in excess of that recommended in the Test Guidelines (1.5 pH units after 72 hours). This was considered to have had no adverse effect on the results of the study given that the increase in cell concentration in the control cultures exceeded the validation criterion given in the Test Guidelines.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 7.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 7.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

This study showed that there were no toxic effects at saturation.

Any other information on results incl. tables

ErC10 (0 to 72 hour): >100% v/v saturated solution ErC20 (0 to 72 hour): >100% v/v saturated solution ErC50 (0 to 72 hour): >100% v/v saturated solution

Where ErCx is the test concentration that reduced growth rate by x%.

Statistical analysis of the growth rate data was carried out for the control and all test concentrations using one way analysis of variance incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf, 1981) and Dunnett's multiple comparison procedure for comparing several treatments with a control (Dunnett, 1955). There were no statistically significant differences (P≥0.05), between the control and any test group and therefore the NOEC based on growth rate was 100% v/v saturated solution.

EyC10 (0 to 72 hour):  >100% v/v saturated solution EyC20 (0 to 72 hour):  >100% v/v saturated solution EyC50 (0 to 72 hour):  >100% v/v saturated solution

Where EyCx is the test concentration that reduced yield by x%.

Statistical analysis of the yield data was carried out.  There were no statistically significant differences (P≥0.05), between the control and any test group and therefore the NOEC based on yield was 100% v/v saturated solution.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

At saturation of the media by test compound, there were no effects observed, and therefore the nominal saturation dose, 7.9mg/L, is considered to be the No Observed Effect Concentration (NOEC) and the EC50 value.

Executive summary:

The 72h EC50 was determined to be > 7.9 mg/L and the 72h NOEC was 7.9 mg/L.