Methyl ricinoleate

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:

28 Aug - 01 Sep 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with restrictions (no analytical monitoring), only three replicates used.

Qualifier:

according to guideline

Guideline:

other: Annex of EU guideline 92/69/EWG, adopted 1992

Qualifier:

according to guideline

Guideline:

other: VCI concept draft for (acute) aquatic testing of poorly soluble substances, adopted 1994

Principles of method if other than guideline:

The VCI concept schedules a maximum of 4 test steps:(1) Limit test at nominal 100 mg/L without separation of phases(2) Limit test at nominal 100 mg/L after separation of insoluble components(3) Testing at saturation level: 3- to 5-fold saturation concentration and separation of insoluble components(4) Testing of dilutions of the saturated solution prepared in (3)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)- Method 1: 100 mg/L after separation of undissolved material:111 mg test substance were added to 1 L deionised water and continuously stirred for 24 h using a magnetic stirrer. Insoluble parts of the test substance were separated by filtration through a glass fibre filter pre-treated with 1 M NaOH.- Method 2: 100 mg/L direct weighing without separation of undissolved material:After weighing, the test substance solution was incubated for 24 h on a shaker.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM- Source (laboratory, culture collection): Laboratory stock at Henkel KGaA, originally obtained from Universität Göttingen, Institute of Plant Physiology- Age of inoculum (at test initiation): 3 to 4 days pre-incubation in test medium without test substanceACCLIMATION- Culturing media and conditions (same as test or not): same

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

no data

Test temperature:

23 °C

pH:

Method 1: 6.9 - 7.0 at test startMethod 2: 6.8 - 7.2 at test end

Dissolved oxygen:

no data

Nominal and measured concentrations:

Nominal test substance concentration: Method 1: 100 mg/L (with filtration)Method 2: 100 mg/L (without filtration)

Details on test conditions:

TEST SYSTEM- Test vessel: Erlenmeyer flasks- Size, fill volume: 300 mL, 100 mL- Initial cells density: 10,000 cells/mL- Control end cells density: 220,000 cells/mL- No. of vessels per concentration (replicates): 3- No. of vessels per control (replicates): 3GROWTH MEDIUM- Standard medium used: mineral salt medium following DIN 38412/9- Detailed composition if non-standard medium was used: no details givenOTHER TEST CONDITIONS- Sterile test conditions: Bacterial growth was observed in the test series with direct weighing of the test substance.- Photoperiod: continuous illumination- Light intensity and quality: max. 300 lux with daylight spectrum- Shaking: 120 rpmEFFECT PARAMETERS MEASURED (with observation intervals if applicable) :- Determination of cell concentrations: counting chamber

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Remarks on result:

other: Method 1: with filtration

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 2: without filtration

Details on results:

- Exponential growth in the control (for algal test): yes- Other: In the test series with direct weighing of the test substance, turbidity of the medium occured due to growth of bacteria- Effect concentrations exceeded solubility of substance in test medium in part 2 of the study.The decrease in the algal growth observed in the replicates without filtration are presumably due to physical effects.

Algal growth rate:

Method 1 (with filtration): average growth inhibition: 0%

Method 2 (without filtration): average growth inhibition: 61.2%

Algal biomass:

Method 1 (with filtration): average growth inhibition: 0%

Method 2 (without filtration): average growth inhibition: 92.7%

Part 2 of the study (after separation of undissolved test substance): No negative effects at the level of water solubility (< 0.025 mg/L).

Based on these results it can be assumed that the effects occurring in the presence of undissolved test substance components are due to the physical effects of undissolved fractions rather than to systemic toxicity.

Table 1: Cell concentrations after 24, 48 and 72 h of exposure to the test substance

Test Concentration (mg/L)	Cell Concentration (cells/mL)
	24 h	48 h	72 h
0	3.0E04	9.0E04	2.2E05
100 (method 2)	0	2.3E04	3.3E04
100 (method 1)	2.0E04	1.5E05	3.6E05

Description of key information

No effects up to the limit of water solubility

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

Additional information

Experimental data on the acute toxicity of methyl ricinoleate (CAS 141-24-2) to aquatic algae are not available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, toxicity data from structurally related substance Fatty acids, C16-18 and C18 unsaturated isobutyl esters (CAS No. 84988-79-4) was used to assess the toxicity to algae in a read across approach.

Based on the high degree of similarity between the structural and physico-chemical properties of the target and source substance, the source substance is considered as a suitable representative for the evaluation of the short-term toxicity of the target substance to aquatic invertebrates. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

The study on the read across substance Fatty acids, C16-18 and C18 unsaturated isobutyl esters (CAS No. 84988-79-4) was performed as a limit test according to the EU guideline 92/69/EWG and GLP (BASF, 1995). The test organism Scenedesmus subspicatus was exposed to the test substance in a static system for 72 hours, at the nominal test concentration 100 mg/L. The test was performed with and without separation of undissolved test material (the test substance was separated by filtration). With undissolved test substance present, algal growth was significantly inhibited. An inhibition of the algal growth was not observed in the filtered test solutions. The inhibition can be thus regarded as physical effect caused by undissolved material. It can be concluded that the substance has no toxic effects on test organism up to the limit of water solubility.

Based on the results obtained for the structurally related read across substance an acute toxicity of methyl ricinoleate (CAS 141-24-2) to aquatic algae is not expected within the limit of its water solubility.