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Ecotoxicological information

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:
2015-09-07 - 2015-12-18
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The GLP-Study was performed according to an internationally accepted guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
The temperature in the experiment was in a range of 20.8 - 23.0 °C and therefore slightly lower than stated in the study plan. Because normal growth was observed, this can be stated as uncritical.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Test material form:
semi-solid (amorphous): gel
Remarks:
migrated information: paste
Details on test material:
Purity: 99.98% UVCB substance, 0.02% Tocopherol

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
The water-accommodated fraction (WAF) was prepared for the test. This was done by mixing the load of 100.8 mg/L with the corresponding amount of nutrient medium (demin-eralised water enriched with minerals but without algae) and shaking vigorously for 23 hours. The resulting solution was filtrated through 0.45 µm nylon filters.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Specification: Unicellular freshwater green alga.
Genus Desmodesmus
Species subspicatus
SAG Strain Number 86.81
Taxonomic position Chlorophyta - Chlorophyceae
Origin and Culture:
The culture of Desmodesmus subspicatus was obtained in February 2014 by MBM Sci-encebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). 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:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
20.8 - 23.0°C
pH:
7.6 - 8.2
Details on test conditions:
At the beginning and at the end of the test, the content of the test item in the test solutions was estimated using DOC-determination.
Because of the very low solubility in test medium, no calculation from carbon content of the test item and DOC measurement was possible. The measured DOC concentrations in the treatment were in a similar low range as the blank control.
Therefore the determination of the biological results was based on the nominal concentration.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate K2Cr2O7

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 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:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Results with reference substance (positive control):
72h ErC50 1.1 mg/L
72h EyC50 0.39 mg/L

Any other information on results incl. tables

Growth Rate, Yield

Nominal Concentration in mg/L

Parameter

Growth Rate

(0-72h) [day-1]

Yield (0-72h)
[Cell Concentration/mL]

Blank control

Mean

1.60

396884

SD

0.06

61309

100

Mean

1.64

442699

SD

0.05

68253

Inhibition

Nominal concentration in mg/L

% Inhibition

Growth Rate (0-72h)

Yield (0-72h)

Blank control

0

0

100

-2.28

-11.54

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of Phytosteryl Macadamiate to aquatic algae was determined according to OECD Guideline 201 (Alga, Growth Inhibition Test). Under laboratory conditions no inhibitory effects of the test item on average specific growth rate and yield were determined. The NOEC (no observed effect concentration) after 72 hours was determined to be ≥ 100 mg/L.
Executive summary:

One valid experiment was performed.

The study was performed using 1 concentration containing 100 mg/L nominal concentration. Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the absorption of the solutions at 440 nm every 24 hours with a spectral photometer. The cell density of the cultures was calculated based on the correlation curve between the absorption and the cell density of the cultures determined with a cell counter. Growth rate µ and the yield[1]were determined from the cell number at the respective observation times.

Inhibition of algal growth was not observed in the treatment.

At the beginning and at the end of the test, the content of the test item in the test solutions was estimated by DOC measurement. The measured DOC concentrations in the treatment were in the same low range as in the control. Therefore no calculation from carbon content of the test item and DOC measurement was possible. The determination of the results was based on the nominal concentrations which represent the nominal loadings of the test item.

The 72h-EC50s of potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory.

The following results for the test item PHYTOSTERYL MACADAMIATE were determined:


Endpoint

NOEC

LOEC

EC10

EC50

Growth Rate

≥ 100 mg/L

> 100 mg/L

> 100 mg/L

> 100 mg/L

Yield

≥ 100 mg/L

> 100 mg/L

> 100 mg/L

> 100 mg/L

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