Fatty acids, coco, iso-Bu esters

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: redworms
- Source: in-house breed, originally obtained from Regenwurmfarm Tacke
- Age at test initiation: 3 - 6 months
- Mean Weight: 361.3 ± 65.7 mg

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20 ± 2 °C

pH:

Begin: 6.42
End: 6.50

Moisture:

26.1 - 26.5%

Details on test conditions:

TEST SYSTEM
- Test container: 1000 mL glass beaker covered with a perforated foil
- Amount of soil or substrate: 750 g substrate
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): 10% sphagnum peat, 20% kaolin, 70% quartzsand, CaCO3 to adjust pH

OTHER TEST CONDITIONS
- Photoperiod: 24 hours permanent, diffuse light
- Light intensity: 500 Lux

EFFECT PARAMETERS MEASURED: mortality after 7 and 14 d

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: control, 0.2, 2.0 and 20.0 g/kg substance, solvent: Isopropanol
- Results used to determine the conditions for the definitive study: 20 and 30% mortalities after 14 days in all concentrations including control (was explained with residual solvent)

Nominal and measured concentrations:

nominal: 0 and 20000 mg/kg soil

Reference substance (positive control):

yes

Remarks:

Chloracetamid

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 20 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality at end of exposure period: 0% after 14 days at 20000 mg/kg soil and control

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: Concentrations used: control, 0.1, 1.0 and 10 mg/kg soil; 60% in 14 days at 10 mg/kg, 20% mortality at 1.0 mg/kg and 0% mortality at 0.1 mg/kg substrate. LC50(14d) = 6.0 mg/kg dw, NOEC(14d) = 0.1 mg/kg dw
- Total mass of adults at beginning of test: 344.9 mg ± 32.8 mg

Reference 2

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) and the source substance FATTY ACIDS, C16-18, ISOBUTYL ESTERS (CAS 85865-69-6) are both Short Chain Alcohol Esters (SCAE C2-C8) composed by a fatty acid (C16-C18) and a C4 alcohol (isobutanol).
The source and the target substance show therefore the same reactive groups and a similar composition. A read-across to the source is therefore justified.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with organic acids (e. g. stearic acid) in the presence of an acid catalyst. The esterification reaction is started by a transfer of a proton from the acid catalyst to the acid to form an alkyloxonium ion. The carboxylic acid is protonated on its carbonyl oxygen followed by a nucleophilic addition of a molecule of the alcohol to a carbonyl carbon of acid. An intermediate product is formed. This intermediate product loses a water molecule and proton to give an ester. Monoesters are the final product of esterification.

3. ANALOGUE APPROACH JUSTIFICATION
Since both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with an organic acid and therefore share similar/overlapping structural features and functional groups, it is justified to use a read across approach. The source substance has been registered already and its short term toxicity to SOIL MACRORGANISMS except arthropods has been investigated using a grouping of substance and read across approach. It has been concluded that no toxicological short term effects on SOIL MACRORGANISMS except arthropods have been observed for of Fatty acids, C16-18, isobutyl esters (CAS No. 85865-69-6). LC50 > 20,000 mg/kg soil DW for Eisenia fetida (OECD 207) .
The same behaviour is predicted for the target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) .

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

20 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Conclusions:

No toxicological short term effects on SOIL MACRORGANISMS except arthropods have been observed for of Fatty acids, C16-18, isobutyl esters (CAS No. 85865-69-6). LC50 > 20,000 mg/kg soil DW for Eisenia fetida (OECD 207) .
The same behaviour is predicted for the target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) .

Executive summary:

Both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with an organic acid and therefore, share similar/overlapping structural features and functional groups, it is justified to use a read across approach. The source substance has been registered already and its short term toxicity to SOIL MACRORGANISMS except arthropods has been investigated using a grouping of substance and read across approach. It has been concluded that no toxicological short term effects on SOIL MACRORGANISMS except arthropods have been observed for of Fatty acids, C16-18, isobutyl esters (CAS No. 85865-69-6). LC50 > 20,000 mg/kg soil DW for Eisenia fetida (OECD 207) .

The same behaviour is predicted for the target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) .

Description of key information

LC50 > 20,000 mg/kg for Eisenia fetida (OECD 207)

Additional information

There are no studies available on the toxicity of Fatty acids, C16-18, isobutyl esters (CAS No. 85865-69-6) on terrestrial macroorganisms. The assessment was therefore based on a study conducted with the category member isopropyl myristate (CAS No. 110-27-0).

 

The study conducted with isopropyl myristate (CAS No. 110-27-0) was performed as a limit test according to OECD guideline 207 and GLP (Steber, 1999). The test organism Eisenia fetida was exposed to isopropyl myristate in artificial soil for 14 days, at the nominal test concentration 20,000 mg/kg. No mortality occurred during the test period.