2-(3,5-dimethylhex-3-en-2-yloxy)-2-methylpropyl cyclopropanecarboxylate

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 08 July 2016 to 21 September 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals - Effects on Biotic Systems, 2013, 207 Earthworm, Acute Toxicity Test

Version / remarks:

China Guideline

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Solubility in water: 0.014 g/L at 20°C
- Vapour pressure: 0.459 Pa at 20°C
- log Kow: 4.4
- Conditions of storage: Keep in dark place at room temperature (T: 10-30°C, H: <45%)
- Stability at conditions of storage: Dry, well ventilled, preferably full, hermetically sealed.

Batch No. : SC00017257
Purity : 97.6%
Date of Expiry : 15 April, 2018

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

The test substance may be volatile and was added into soil directly. An amount of the test substance was separately added to an appropriate amount of the silica sand, and then incorporation into formulated artificial soil with deionised reverse osmosis water. The treatment groups were prepared by the following test matrix component: See table 6.3.1/1 in "Any other information on materials and methods incl. tables". These were mixed by a mixer respectively with a nominal moisture of 40-60% by mass of the total water-holding capacity with the deionized water. The test matrix components were mixed evenly and distributed to 4 containers.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

The earthworms were purchased from Jiang Su province Jurong Stock Farm. All newly acquired earthworms were quarantined and observed for 14 days prior to use in the test. Earthworms are bred on a substrate consisting of 50% by volume peat and 50% by volume cow manure and kept under 20 +/- 2°C for 7 days prior to testing. The test organisms were with clitellum and were transferred into artificial soil (without test substance) approximately 24 hours prior to the start of the test. At the start of the test, the adult earthworms used originated from the same population, were clitellum and wet weight of 300 to 600 mg.
The earthworms received no food during exposure.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

The measured temperature of the climate chamber remained 20.7 to 21.0°C throughout the study, which was in the range of 18-22°C.

pH:

pH values were 5.98 to 6.40 at initiation and 6.01 to 6.38 at termination.

Moisture:

Soil moisture content were 26.04% to 29.42% at initiation and 26.38% to 29.35% at termination.

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1 litre closed glass vessels
- Amount of soil or substrate: Each container was loaded with approximately 750 g wet weight of the 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 :
A defined artificial soil was used as a basic test substrate with the following composition: Sphagnum peat 10% w/w; Kaolinite clay (Sigma-Aldrich) 20% w/w; Silica sand (screened with 0.2 mm sieve) 70% w/w.
The pH of the artifical soil was adjusted to 6.0 +/- 0.5. Before the start of the test, measured maximum water holding capacity (WHC) of artificial soil was 52%. Moisture content of the test substrate was adjusted to 40-60% by mass of the total WHC with the deionized water. Appropriate moisture content is 21-31%. The water content does not vary with more than 10% from that at the start of the test (OECD 222, 2004).

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity: 610-630 lux

EFFECT PARAMETERS MEASURED :
The total gross weights of the earthworms added to each vessel in the controls and the treatment groups were recorded on Day 0 before addition. The surviving earthworms in each vessel were weighted on Day 14.
Mortalities were recorded 7 and 14 days after the start of treatment. Earthworm and soil were poured out from glass containers to the stainless steel basin on 7 days, counting number, observation, and then after record the surviving earthworms and soil were put back into the corresponding container.

RANGE-FINDING TEST
In the range-finding test, the earthworms were exposed to a series of nominal concentrations of 10, 100 and 1000 mg/kg and blank control, in single replicate. The results showed no mortality occurred in the blank control group and in the 10 and 100 mg/kg treatment groups on the 7th day and 14th day, but in 1000 mg/kg on 7th day, the mortality was 80%, and on 14th day, the mortality was 100%.

Nominal and measured concentrations:

The nominal concentrations of the treatment groups were 95, 153, 244, 391, 625 and 1000 mg test substance/kg dry artificial soil weight.

Reference substance (positive control):

yes

Remarks:

Chloroacetamide

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

361 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI: 327 - 400 mg/kg

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

291 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI: 269 - 315 mg/kg

Details on results:

- Mortalities: See table 6.3.1/2 in "Any other information on results incl. tables". Mortalities in control, 95 and 153 mg/kg group on 7th and 14th day both were 0%. Mortalities in 224 mg/kg group on the 7th day were 17.5% and 14th day were 22.5%. Mortalities in 391 mg/kg group on 7th were 60% and 14th day were 90%. Mortalities in 625 mg/kg group on 7th were 90% and 14th day were 100%. Mortalities in 1000 mg/kg group on 7th and 14th day were 100%.
- Behavioural or pathological symptoms: None
- Body weight: See Table 6.3.1/3 in "Any other information on results incl. tables".

Results with reference substance (positive control):

The validity of the test system and Eisenia fetida is regularly confirmed by determining the LC50 against a reference substance. For this purpose, chloroacetamide was employed. The most recent test was performed from 19th Jan 2016 to 2th Feb 2016 (14 days test). In this study, the reference substance was tested at 5 concentrations of 3.75, 7.50, 15, 30 and 60 mg/kg dry artificial soil weight.
Mortalities were shown to be between 22.5 to 95%. The 14d-LC50 for chloroacetamide was 25.7 mg/kg dry soil weight.
- Results with reference substance valid? yes

Table 6.3.1/2: The mortality of Eisenia fetida exposed to the test substance and control at 7 and 14 days after application in definitive test

Parameter	Blank control		Treatments (mg/kg dry soil weight)
			95		153		244		391		625		1000
Duration (d)	7	14	7	14	7	14	7	14	7	14	7	14	7	14
Number of earthworm	40	40	40	40	40	40	40	40	40	40	40	40	40	40
Number of mortality (A replicate)	0	0	0	0	0	0	1	1	7	10	9	10	10	10
Number of mortality (B replicate)	0	0	0	0	0	0	4	5	8	10	8	10	10	10
Number of mortality (C replicate)	0	0	0	0	0	0	0	0	6	10	9	10	10	10
Number of mortality (D replicate)	0	0	0	0	0	0	2	3	3	6	10	10	10	10
Total	0	0	0	0	0	0	7	9	24	36	36	40	40	40
Mortality (%)	0	0	0	0	0	0	17.5	22.5	60	90	90	100	100	100

Table 6.3.1/3: Number and average body weight of the surviving earthworms at the beginning and the end of the definitive test

Groups			No. of worms Day 0	Mean weight Day 0 (mg)	No. of worms Day 14	Mean weight Day 14 (mg)	Weight reduction 14 days (%) +/- standard deviation
Blank control		A B C D	10 10 10 10	573 552 520 523	10 10 10 10	415 465 488 438	16.43 +/- 8.76 %
Treatment groups (mg/kg dry soil weight)	95	A B C D	10 10 10 10	538 521 528 543	10 10 10 10	489 416 465 470	13.66 +/- 4.69 %
	153	A B C D	10 10 10 10	526 530 552 565	10 10 10 10	490 428 437 421	18.1 +/- 7.96 %
	244	A B C D	10 10 10 10	532 536 544 526	9 5 10 7	434 416 472 366	21.11 +/- 7.28 %
	391	A B C D	10 10 10 10	534 538 570 541	0 0 0 4	- - - -	-
	625	A B C D	10 10 10 10	566 521 563 534	0 0 0 0	- - - -	-
	1000	A B C D	10 10 10 10	535 526 561 557	0 0 0 0	- - - -	-

Validity criteria fulfilled:

yes

Remarks:

The mortality of the earthworm in the blank control group was 0%, which was not more than 10%, so the test was valid.

Conclusions:

Under the conditions of the test, the 7d-LC50 and 14d-LC50 values, for the test substance to earthworm (Eisenia fetida) based on the nominal test concentrations, were 361 mg/kg (95% CI: 327 - 400 mg/kg) and 291 mg/kg (95% CI: 269 - 315 mg/kg) dry soil weight, respectively.

Executive summary:

The acute toxicity of the test substance to Eisenia fetida was determined in a 14 days artificial soil test, according to "Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals - Effects on Biotic Systems, 2013, 207 Earthworm, Acute Toxicity Test" and OECD Guideline 207 (1984) with GLP compliance.

Based on the results of range-finding test, 6 treatment groups and one blank control group, which had four replicates of 10 worms per concentration were included in definitive test. The nominal concentrations of the treatment groups were 95, 153, 244, 391, 625 and 1000 mg/kg dry artificial soil weight. The number of mortalities were determined after 7 and 14 days of exposure.

The mortality of the earthworm in the blank control group was 0%, which was not more than 10%, so the test was valid.

Under the conditions of the test, the 7d-LC50 and 14d-LC50 values, for the test substance to earthworm (Eisenia fetida) based on the nominal test concentrations, were 361 mg/kg (95% CI: 327 - 400 mg/kg) and 291 mg/kg (95% CI: 269 - 315 mg/kg) dry soil weight, respectively.

Description of key information

OECD Guideline 207, GLP, key study, validity 2:

14d-LC50 (Eisenia fetida) = 291 mg/kg dw of soil (95% CL: 269 - 315 mg/kg dw of soil).

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

291 mg/kg soil dw

Additional information

To assess the toxicity of the registered substance to soil macroorganisms, one experimental study is available.

This study was performed according to OECD Guideline No. 207 with GLP compliance to determine the acute toxicity of the registered substance to adult earthworms Eisenia fetida in an artificial soil. Following a preliminary range-finding test, 40 earthworms (4 replicates of 10 worms) were exposed to nominal test concentrations of 95, 153, 244, 391, 625 and 1000 mg/kg dw of soil for a period of 14 days. The number of mortalities were determined after 7 and 14 days exposure. The 14-d LC50 for the test substance to earthworms based on nominal test concentrations was 291 mg/kg dw of soil (95% CL: 269 - 315 mg/kg dw of soil).