Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

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:
Jan 2017 - May 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Details on preparation of test solutions not given
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: 86.81
- Source (laboratory, culture collection): MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen), Germany
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
22.2 – 22.6 °C
pH:
7.6 - 8.6
Nominal and measured concentrations:
Nominal test substance concentrations: 0.1, 0.32, 1.0, 3.2, 10, 32 and 100 mg/L
Mean measured concentrations at 0 h: 0, 0, 0, 1.7, 8.1, 29.6 and 94.3 mg/L
Mean measured concentrations at 72 h: 0, 0, 0, 0.2, 6.1, 26.2 and 87.9 mg/L
Geometric mean: 0, 0, 0, 0.6, 7.0, 27.8 and 91 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: glass flasks, total volume 65 mL
- Type (delete if not applicable): open
- Fill volume: 45 ml
- Initial cells density: 5000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: demineralised water enriched with minerals

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: conintuous illumination
- Light intensity and quality: 4500 LUX

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter after 0, 24, 48 and 72 h

Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
7 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
48 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 91 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
56 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
ErC50 (72 h): 0.80 mg/L (study performed in October 2016)
Reported statistics and error estimates:
Microsoft Excel® and ToxRat® Professional, version 3.2.1.

Inhibition of growth rate and yield

 

 

% Inhibition

Nominal

Concentration in

mg/L

Measured

Concentration in

mg/L

Growth Rate
(0-72h)

Yield
(0-72h)

 

Blank control

--

0

0

0.1

--

9.44

33.47

0.32

--

-1.84

-6.63

1.0

--

2.97

12.93

3.2

0.6

-3.50

-13.97

10

7.0

-0.04

1.29

32

27.8

6.23

23.19

100

91.0

14.29

46.09

Negative inhibition values indicate a stimulation of algal growth compared to the blank control.

Description of key information

EC50 (72 h) >91 mg/L (measured, geom. mean)

Key value for chemical safety assessment

EC50 for freshwater algae:
91 mg/L
EC10 or NOEC for freshwater algae:
7 mg/L

Additional information

The toxicity of the target substance (EC 943-330-9) to aquatic algae was tested in a study following OECD 201 (GLP). Green algae (Desmodesmus subspicatus) were exposed to nominal test substance concentrations of 0.1, 0.32, 1.0, 3.2, 10, 32 and 100 mg/L. The test substance concentration was verified by DOC analysis at test start and test termination after 72 hours. The geometric mean measured concentrations were 0, 0, 0, 0.6, 7.0, 27.8 and 91 mg/L. Significant inhibition of algal growth was observed at measured substance concentrations of 27.8 mg/L and 91.0 mg/L (6.23% and 14.29% inhibition respectively). Based on the algal growth rate an EC50 (72 h) >91 mg/L (measured, geom. mean) was determined. The derived NOEC (72 h) was 7 mg/L (measured, geom. mean).