Reaction products of behenic acid, Eicosadioic acid and Polyglyceryl-10

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:

01. February - 04. June 2018

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)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name Nomcort HK-P
Batch no. 7-4-C
Appearance white/pale yellow waxy solid
Composition Polyglyceryl-10 Behenate / Eicosadioate
CAS No. 457632-32-5
EINECS-No. 478-920-0
Purity 100%
Homogeneity homogeneous
Volatility 0.00000001 hPa (20°C)
Stability H2O: unknown; EtOH: unknown; acetone: unknown; CH3CN: unknown; DMSO: unknown
Solubility H2O: 0.1-1 g/L; EtOH: unknown; acetone: unknown; CH3CN: unknown; DMSO: unknown
Production date 17. Apr. 2017
Expiry date 17. Apr. 2020
Storage Room Temperature (20 ± 5°C)

Analytical monitoring:

yes

Details on sampling:

The content of DOC in the test vessels was measured at the start and at the end of the test.

Vehicle:

no

Details on test solutions:

The water-accommodated fraction (WAF) of the concentration to be tested was prepared. This was done by weighing 99.75 mg/L of test item, adding the appropriate amount of algal medium (demineralised water enriched with minerals but without algae) and shaking for 24.5 hours. After membrane filtration, the solution was used to prepare the lower treatments.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Selection of the test system was made following the proposal of the guidelines.
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 January 2016 by MBM Sciencebridge 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.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

At the end of the test, the treatments were examined microscopically in order to assess the appearance of the algae and detect abnormalities (e.g. caused by the exposure to the test item).

Hardness:

The algal medium corresponds to the OECD TG 201 medium.

Test temperature:

21.7 – 23.0 °C

pH:

7.6 - 8.2

Dissolved oxygen:

not determined

Salinity:

The algal medium corresponds to the OECD TG 201 medium.

Conductivity:

The algal medium corresponds to the OECD TG 201 medium.

Nominal and measured concentrations:

1 / 3.2 / 10 / 32 / 100 mg/L nominal concentration
In the 4 highest concentrations the measured concentrations were in a range of 11 % - 30 % of the nominal concentrations .Therefore, the determination of the results was based on the geometric mean of the measured concentrations. The measured DOC concentration in the lowest concentrated treatment was in the same range as in the control. Therefore, this concentration was not used for evaluation. This can be stated as uncritical because no toxicity was observed at this concentration.
The details are given in the tables section

Details on test conditions:

7.3 Experimental Conditions
Date: 13. – 16. February 2018
Treatments tested: 1 / 3.2 / 10 / 32 / 100 mg/L nominal concentration
The concentrations to be tested are based on a non GLP pre-test
Number of replicates: 6 replicates for the blank control
3 replicates for each treatment
Vessels: glass flasks total volume 65 mL
Duration: 72 hours
Lighting: 5000 lux
Temperature: 21.7 – 23.0 °C
Replicates (Blank control): 45 ±1 ml algal medium and algae
Replicates (Treatments): 45 ±1 ml test solution and algae

Reference substance (positive control):

yes

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

8.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Results with reference substance (positive control):

The results of the last study with the positive control K2Cr2O7 are presented in the following table. The study was performed under GLP conditions in August/ September 2017 .
Biological Results of K2Cr2O7
Parameter Value 95% confidence interval
72h ErC50 0.90 mg/L 0.77 - 1.1 mg/L
72h EyC50 0.42 mg/L 0.35 - 0.51 mg/L

Reported statistics and error estimates:

Calculation of results was performed with the help of validated software. Calculation was performed with Microsoft Excel® and ToxRat® Professional, version 3.2.1.
Note: All calculations are performed with unrounded values. Therefore, re-calculation with rounded values may lead to slightly different results.

Validity criteria fulfilled:

yes

Conclusions:

Nomcort HK-P is tested for Toxicity against Algae according OECD Guideline 201.
The substance shows toxic effects on Algae at certain concentrations:
Endpoint     NOEC LOEC        EC10 EC50
Growth Rate 0.6 mg/L    2.0 mg/L        8.7 mg/L   n.d.
Yield                 0.6 mg/L    2.0 mg/L        1.4 mg/L   21 mg/L
n.d. not determined due to mathematical reasons or inappropriate data

Executive summary:

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 1.0 to 100 mg/L. Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yield  were determined from the cell number at the respective observation times.

Significant inhibition of algal growth was observed at the two highest concentrations.

The water-accommodated fraction (WAF) was prepared for the test. This was done by mixing the nominal load with the corresponding amount of algal medium and shaking vigorously for 24.5 hours. The resulting solution was filtrated through 0.45 µm PTFE filters.

The lower treatments were prepared by dilution of this WAF with nutrient medium. This was in accordance OECD Guidance Document No. 23 where is stated that serial dilution of a stock WAF may be the only applicable method for chemicals being toxic at concentra-tions of 1 mg/L or lower.

At the start and at the end of the test, the content of the test item in the test solutions was estimated by determination of the dissolved organic carbon (DOC) content in the test solutions using a carbon analyser.

In the 4 highest concentrations the measured concentrations were in a range of 11 % - 30 % of the nominal concentrations .Therefore, the determination of the results was based on the geometric mean of the measured concentrations. The measured DOC concentration in the lowest concentrated treatment was in the same range as in the control. Therefore this concentration was not used for evaluation. This can be stated as uncritical because no toxicity was observed at this concentration.

Due to the low inhibition the EC50 values can only be specified as a limit value.

The following results for the test item Nomcort HK-P were determined:

Results of the test item

Endpoint              NOEC       LOEC       EC10       EC50

Growth Rate          0.6 mg/L       2.0 mg/L       8.7 mg/L       n.d.

Yield                     0.6 mg/L       2.0 mg/L       1.4 mg/L       21 mg/L

n.d. not determined due to mathematical reasons or inappropriate data

Description of key information

One Guideline Study on acute Toxicity to Algae available.

Key value for chemical safety assessment

EC50 for freshwater algae:

21 mg/L

Additional information

Reported is the EC50 (yield / biomass)