Reaction mass of bis[2-[2-(2-butoxyethoxy)ethoxy]ethyl]adipate and 2-[2-(2-butoxyethoxy)ethoxy]ethyl (3,6,9,12-tetraoxahexadecyl)adipate

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:

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

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

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).