Decanoic acid, mixed esters with heptanoic acid, octanoic acid and trimethylolpropane

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

25 Oct 2012 - 20 Feb 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study. For read-across, maximum reliability score is 2.

Qualifier:

according to guideline

Guideline:

OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 11268-2 (Effects of Pollutants on Earthworms. 2. Determination of Effects on Reproduction)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Details on preparation and application of test substrate:

- Method of mixing into soil (if used): A stock solution was prepared by dissolving the test substance in aceton (250 mg test substance/mL acetone). A serial dilution of the stock solution was prepared for the required test substance concentrations. The solutions were subsequently mixed with sand. The mixture was added to 496.4 g ww of artificial soil. 2.8 g calcium carbonate, 5 g food (horse manure), and 143.6 mL purified water were added and the substate was mixed in a laboratory mixer.
- Chemical name of vehicle: acetone
- Evaporation of vehicle before use: yes

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Source: Blades Biological Ltd, Cowden, United Kingdom
- Age at test initiation: adult, with clitellum
- Weight at test initiation (range): 310 - 594 mg

ACCLIMATION
- Acclimation period: 3 days
- Acclimation conditions : same as in test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

56 d

Remarks:

After 28 days the adult earthworms were removed and the cocoons and juveniles remained in the test substrate for another 28 days

Test temperature:

19 - 22 °C

pH:

6.1 - 6.3

Moisture:

33-41% of water holding capacity (WHC: 64.2 g /100 g dry soil).

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Plastic boxes (16.5 cx 12 x 6.5 cm, area about 200 cm2)
- Amount of soil or substrate: 650 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8 (incl. vehicle control)

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): 10% Sphagnum peat, 20% Kaolin clay, 69% Sand

OTHER TEST CONDITIONS
- Photoperiod: 16:8 h day-night regime
- Light intensity: 656-749 Lux

EFFECT PARAMETERS MEASURED:
Mortality and body weight of adult earthworms after 28 days, reproduction rate after 56 days

Nominal and measured concentrations:

Nominal test substance concentrations: 62.5, 125, 250, 500 and 1000 mg/kg dry soil.

Reference substance (positive control):

yes

Remarks:

Carbendazim, Batch No.: 12001/03

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

- Mortality at end of exposure period: control: no mortality observed; test substance: <2.5%

Results with reference substance (positive control):

75% mortality at a reference substance concentration of 8.33 mg/kg dry soil

Reported statistics and error estimates:

Changes in body weight and differences regarding mortalilty between treatment and control were evaluated by multiple Dunnett t-test (Dunnett, 1955; Dunnett, 1964) after a one-way analysis of variance (ANOVA).
The body weight change of the surviving worms in the positive control was compared to the control and was statistically evaluated by means of a Student-t test (Sachs, 1984).
Reproduction rates were analysed using a multiple Dunnett t-test [Dunnett, 1955; Dunnett, 1964] after a one-way analysis of variance (ANOVA).

Mortality, number of hatched juveniles and changes in body weight

Treatment (mg/kg dry weight)	Mortality (%) after a 4-week exposure	Juveniles per vessel (mean)	Juvenils per vessel (% of control)	Mean body weight per worm (% difference from test start)
Control	0	168	100	9
62.5	0	137	81	17
125	0	141	84	14
250	2.5	150	90	15
500	2.5	155	92	17
1000	0	152	90	14
Reference substance	7.5	0	0	-54

Description of key information

 No relevant studies are available for decanoic acid, mixed esters with heptanoic acid, octanoic acid and trimethylolpropane. An earthworm reproduction study is available for read-across substance, CAS 78-16-0.

As discussed in ECHA Decision number CCH-D-2114343360-61-01/F, ECHA notes that additional toxicity testing on fish and aquatic invertebrates is being requested as part of the present Decision and the results of these tests may subsequently allow the derivation of PNECwater. If the results allow the subsequent derivation of a PNECwater, the Registrant may consider the ITS as recommended in section R.7.11.6., Chapter R.7c of the ECHA Guidance on information requirements and chemical safety assessment (May 2008), and determine the need for further testing on terrestrial organisms. In this case it may be possible to waive the corresponding terrestrial toxicity tests by including a justified argument for adaptation of Annex IX, 9.4.3. and Annex X, 9.4.6. or of Annex IX, 9.4.1. and Annex X, 9.4.4. in the registration dossier.

As discussed above, the Daphnia study is still in progress due to significant analytical issues. Once the study is completed, then the ITS will be evaluated, and determined if these studies are actually required. On the basis of existing study data, the substance is considered to be non-toxic and biodegradable.  Structural analogues do not show toxicity, nor does existing study data on soil micro-organisms.  The registrant considers that it is highly likely that the ITS will demonstrate this fact.  Therefore a decision on whether to conduct these tests or not will be taken once the ITS investigation can be completed.

Additional information

An earthworm reproduction study (in accordance with OECD Guideline 222) was conducted with read-across substance, CAS 78-16-0. The NOEC (28 day) based on mortality was determined to be =/> 1000 mg/kg soil dw and the NOEC (56 day) based on reproduction was determined to be =/> 1000 mg/kg soil dw. Therefore, by read-across, the test substance is not expected to have toxic effects on soil macroorganisms.

A report justifying the read-across approach is included in IUCLID Chapter 13.