4-[fluoro(dimethyl)silyl]butanenitrile

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:

October 5, 2016 - March 14, 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

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted 23. Mar. 2006, Annex 5 corrected: 28 July 2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-[fluoro(dimethyl)silyl]butanenitrile

EC Number:

812-925-4

Cas Number:

1639345-42-8

Molecular formula:

C6H12FNSi

IUPAC Name:

4-[fluoro(dimethyl)silyl]butanenitrile

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

During non GLP-pre-tests and this study the test item was obviously not soluble at the highest test item concentration of 100 mg/L. Therefore the water-accommodated fractions
(WAF) were prepared for the test for each concentration individually. This was done by weighing each nominal load, adding the corresponding amount of demineralised water and
shaking vigorously for 23 hours. The resulting solutions were filtrated through 0.45 μm PTFE filters. After filtration, the required amounts of minerals were added.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
-Genus: Desmodesmus
-Species: subspicatus
-SAG Strain Number: 86.81
-Taxonomic position: Chlorophyta - Chlorophyceae
- Source (laboratory, culture collection): MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen)
- Method of cultivation: The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

not mentioned in the report

Test temperature:

22.4 – 22.6 °C

pH:

blank control, 4.6 / 10 / 22 / 46 mg/L nominal concentration:7.1 - 7.7
100 mg/L nominal concentration:4.4 - 5.0

Dissolved oxygen:

not mentioned in the report

Salinity:

not applicable

Conductivity:

not mentioned in the report

Nominal and measured concentrations:

The measured concentrations lay between 75 % and 96 % of the nominal concentrations at the beginning of the test and between 96 % and 101 % of the nominal concentrations at the end of the test. Only in the lowest concentration the measured concentration was lower than 80 % of the nominal concentration. As this treatment was not necessary for evaluation of the biological results it was excluded from the determination of the biological results. Therefore, the determination of the results was based on the nominal concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks, total volume 65 mL
- Initial cells density: 4*10^3 cells/mL

- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Light intensity and quality: 4500 Lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter

TEST CONCENTRATIONS
- Range finding study: 1 / 10 / 100 mg/L
- Test concentrations: 4.6 / 10 / 22 / 46 / 100 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydolysis products

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

growth rate

Details on results:

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

Results with reference substance (positive control):

Biological Results of K2Cr2O7:
Parameter Value 95% confidence interval
72h ErC50 0.91 mg/L 0.80 – 1.0 mg/L
72h EyC50 0.66 mg/L 0.46 – 0.95 mg/L

The 72h-EC50s of potassium dichromate were determined in a separate reference test. For the estimation of the 72h-EC50s of the positive control, the fits showed sufficient statistical correspondence of the data with the dose-response-equation. The values were within the range of the laboratory.

Reported statistics and error estimates:

There were no inhibitory effects observed up to 46 mg/L in the test and therefore statistical analysis of the results was not required. (the highest treatment of 100 mg/Lwas excluded from the determination of the biological results because the pH value was significantly lower than in all other treatments
and the blank control. Therefore, the weakness of algal growth and its strongly scattering inhibition values is supposed to be the result from the very low pH.)

Any other information on results incl. tables

Table 1 Calculated Test item Concentrations

 

Nominal Concentration Test Item	Calculated Concentration Test Item t = 0 h	Calculated Concentration Test Item t = 72 h	% of Nominal concentration t = 0 h	% of Nominal concentration t = 72 h
mg/L	mg/L	mg/L	%	%
Blank control	--	--	--	--
4.6	3.4	4.7	75	101
10	8.8	9.8	88	98
22	20.1	21.0	92	96
46	43.3	44.0	94	96
100	96.3	98.0	96	98

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

A 72 h EC50 of > 46 mg/L, and a 72 h NOEC of 46 mg/L have been determined for the effects of the test substance on growth rate of Desmodesmus subspicatus. The results are expressed relative to nominal concentrations of the test substance. However, the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products.