1,3-bis(2,4,4-trimethylpentan-2-yl)trisulfane

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:

27 June 2016 - 18 August 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Description/Appearance: Pale yellow liquid
Batch Number: L002
Purity: 95.4%
Storage Conditions: Room temperature, in the dark
Expiry Date : 15 August 2016

Analytical monitoring:

yes

Details on sampling:

- Concentrations: stock solution of 1000 mg/L (nominal concentration)
- Sampling method: chromatography
- Sample storage conditions before analysis: frozen

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Centrifugation and filtration
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): any undissolved test item was removed by filtration through a 0.2 µm filter

The test item was prepared using a saturated solution method of preparation at an initial loading rate of 100 mg/L, stirred for a period of 24 hours prior to the removal of any undissolved test item by filtration through a 0.2 μm filter (first approximate 1 liter discarded) to produce a 100% v/v saturated solution.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: CCAP 278/4
- Source: culture collection

Test type:

static

Water media type:

other: deionised reverse osmosis water

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

24 ± 1 °C

pH:

pH 8.6 - pH 8.7

Nominal and measured concentrations:

The range-finding test: 0.10, 1.0, 10 and 100% v/v saturated solution.
The definitive test: 100% v/v saturated solution.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass conical flasks were plugged with polyurethane foam bungs
- Type: closed
- Material, size, headspace, fill volume: 250 mL glass conical flasks
- Aeration: through polyurethane foam bungs
- Initial cells density: 5.00 x 10^3 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity and quality: continuous illumination (intensity approximately 7000 lux) provided by warm white lighting (380 – 730 nm)

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

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.10, 1.0, 10 and 100% v/v saturated solution.
- Results used to determine the conditions for the definitive study: See table 1

Reference substance (positive control):

yes

Remarks:

The positive control used potassium dichromate and was conducted between 07 December 2015 and 10 December 2015.

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v Saturated Solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v Saturated Solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Details on results:

See table 2

Results with reference substance (positive control):

Egrowth rateC50 (0 – 72 h): 1.5 mg/L; 95% confidence limits 1.3 – 1.7 mg/L
EyieldC50 (0 – 72 h): 0.79 mg/L; 95% confidence limits 0.70 – 0.89 mg/L

Reported statistics and error estimates:

A Students t-test was carried out on the growth rate and yield data.

Table2            Cell Densities and pH Values in the Definitive Test

Nominal Concentration (% v/v Saturated Solution)		pH	Cell Densities* (cells per mL)				pH
		0 h	0 h	25 h	48 h	72 h	72 h
Control	R1**	8.6	5.00E+03	2.25E+04	1.12E+04	1.98E+04	8.7
	R2		5.00E+03	2.24E+04	1.48E+05	6.80E+05
	R3		5.00E+03	2.73E+04	1.58E+05	8.22E+05
	R4		5.00E+03	2.92E+04	1.62E+05	8.15E+05
	R5		5.00E+03	2.81E+04	1.45E+05	8.50E+05
	R6		5.00E+03	2.37E+04	1.52E+05	7.41E+05
	Mean		5.00E+03	2.55E+04	1.29E+05	6.55E+05
100	R1	8.6	5.00E+03	2.68E+04	1.66E+05	8.42E+05	8.6
	R2		5.00E+03	2.63E+04	1.38E+05	7.27E+05
	R3		5.00E+03	2.92E+04	1.61E+05	7.50E+05
	R4		5.00E+03	2.72E+04	1.59E+05	6.41E+05
	R5		5.00E+03	2.72E+04	1.49E+05	7.13E+05
	R6		5.00E+03	2.66E+04	1.62E+05	8.68E+05
	Mean		5.00E+03	2.72E+04	1.56E+05	7.57E+05

 

*    Cell densities represent the mean number of cells per mL calculated from the mean of the cell counts from 3 counts for each of the replicate flasks.

R₁- R₆= Replicates 1 to 6

**Lack of growth observed, data omitted from statistical analysis calculations, no impact considered on test.

**Lack of growth observed, data omitted from statistical analysis calculations, no impact considered on test.

Validity criteria fulfilled:

yes

Conclusions:

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

Description of key information

72 hour toxicity study:

EC₅₀ > 100 % v/v saturated solution

No Observed Effect Concentration: 100 % v/v saturated solution

Additional information

An algal growth inhibition study was conducted (Envigo Research Limited, 2016, Study BC97KC) to determine the effect of DAILUBE IS-30 on the growth of Pseudokirchneriella subcapitata (previous names: Selenastrum capricornutum). The study was conducted according to OECD test guideline 201 and EC method C.3, and in compliance with GLP.

Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation. 6 replicates of algal cultures were exposed to 100% v/v saturated solution of DAILUBE IS-30 under continuous illumination for 72 hours at a temperature of 24 ± 1 °C under static test conditions. Six replicate control cultures were also incubated concurrently with the test samples.

The growth rate and yield of Pseudokirchneriella subcapitata were not affected by the presence of DAILUBE IS-30 at a nominal test concentration of 100% v/v saturated solution over the 72-Hour exposure period. There were no abnormalities detected in any of the control or test cultures at 72 hours. The EC50 in terms of both biomass and growth rate was greater than 100% v/v saturated solution.