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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
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):
Pseudokirchneriella subcapitata (previous names: Raphidocelis 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
pH:
pH 8.6 - pH 8.7
Nominal and measured concentrations:
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 103 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 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

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

Key value for chemical safety assessment

EC50 for freshwater algae:
100
EC10 or NOEC for freshwater algae:
100

Additional information

EC50: > 100 % v/v saturated solution and No Observed Effect Concentration: 100 % v/v saturated solution as the test item was not soluble.