Fatty acids, coco, iso-Bu esters

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

12 - 15 Sep 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: VCI concept for the acute aquatic testing of hardly soluble substances from 31st Jan 1994

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Isopropyl myristate

EC Number:

203-751-4

EC Name:

Isopropyl myristate

Cas Number:

110-27-0

Molecular formula:

C17H34O2

IUPAC Name:

isopropyl myristate

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method 1: 100 mg/L nominal: Direct weighing-in of TS in Aqua bidest, shaking for 24 h
- Method 2: 100 mg/L filtered test solution: Direct weighing-in of 111 TS in 1 L Aqua bidest, stirring over a period of 24 h; filtration through glass fibre filter where unsoluble residues are removed, preconditioning of the glass fibre filter with 1 mol NaOH

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): laboratory culture, source Institute of Plant physiology, University of Göttingen, Germany
- Method of cultivation: 10000 cells/mL used as initial cell count for renewed cultures

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

21.9 °C

pH:

Test begin: 7.9
Test end: 9.1-9.4 (control); 9.4 (test substance, method 1), 7.8 (test substance, method 2)

Nominal and measured concentrations:

100 mg/L (nominal) as emulsion (method 1) and as filtered test solution (method 2)

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flask
- Material, size, headspace, fill volume: 100 mL test solution
- Initial cells density: 10000 cells/mL
- Control end cells density: 790000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: according to DIN 38412 part 9, mineral salt medium

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Photoperiod: 24 hours, permanent
- Light intensity and quality: 300 Lux
- other: shaking at 120 rounds per minute

EFFECT PARAMETERS MEASURED: growth
- Determination of cell concentrations: counting chamber (Thoma chamber)
- Determination of cell number at 24, 48 and 72 h

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: method 1

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.05

Nominal / measured:

meas. (not specified)

Conc. based on:

other: filtered test solution

Basis for effect:

growth rate

Remarks on result:

other: method 2

Details on results:

- Exponential growth in the control (for algal test): yes
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
Method 1: turbidity was observed in the test solution at all observation times. Method 2: no turbidity of the test solution (filtered).
The biomass was inhibited to 86.8% (area under the curve) and the growth rate was inhibited to 68.3% at 100 mg/L with method 1; the effects are discussed to be caused by the physical effect caused by undissolved chemical substance rather than a systemic toxic effect
- Effect concentrations exceeding solubility of substance in test medium: The limit solubility of the TS is approximately 0.05 mg/L.

Any other information on results incl. tables

Cells/mL counted with Thoma chambers for the different test solutions:

Concentration of TS	Incubation time (in h)
	24	48	72
Control	63000	290000	790000
100 mg/L emulsion (method 1)	27000	73000	40000
100 mg/L filtrate (method 2)	73000	290000	820000