3,5-bis(difluoromethyl)-1H-pyrazole

Toxicity to terrestrial arthropods

Administrative data

Endpoint:

toxicity to terrestrial arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan. 2019 - Feb. 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 226 (Predatory Mite (Hypoaspis (Geolaelaps) Aculeifer) Reproduction Test in Soil)

Version / remarks:

2016

GLP compliance:

yes (incl. QA statement)

Application method:

soil

Test material

Test material information

Constituent 1

Reference substance name:

3,5-bis(difluoromethyl)-1H-pyrazole

EC Number:

814-072-3

Cas Number:

77614-79-0

Molecular formula:

C5H4F4N2

IUPAC Name:

3,5-bis(difluoromethyl)-1H-pyrazole

Sampling and analysis

Analytical monitoring:

no

Test substrate

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

- Method of mixing into soil: Dissolution of the test item in acetone. Then application onto 5g quartz sand.
- Controls: Control and solvent control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone + Quartz sand
- Evaporation of vehicle before use: Yes
- Volume of test solution applied: 1 mL of acetone solution onto 5 g of quartz sand for 500 g d.w. of artificial soil

Test organisms

Test organisms (species):

Hypoaspis aculeifer

Animal group:

Acari (soil-dwelling predatory mite)

Details on test organisms:

TEST ORGANISM
- Common name: Hypoaspis aculeifer
- Source: Inhouse breeding since 2002, strain originated from ECT Oekotoxikologie GmbH
- Age at test initiation: 28 days
- Stage at test initiation: Adult, fertilized, female
- Kept according to standard practices: Yes


ACCLIMATION
- Acclimation conditions: Breeding on a mixture of Plaster of Paris and activated charcoal and demineralised water (10:1.25:12.5 w/w) at room temperature in the dark
- Feeding: Panagrellus redivivus (nematodes) which were bred onwatered oak flakes

Study design

Study type:

laboratory study

Limit test:

no

Total exposure duration:

14 d

Test conditions

Test temperature:

18 - 22 °C

pH (if soil or dung study):

5.36 - 5.95 in all treatments and controls at the start and the end of the experiment

Humidity:

43.84 - 53.26 % of max. WHC in all treatments and controls at the start and the end of the experiment

Photoperiod and lighting:

16 h / 8 h light / dark
Light intensity 400 - 800 lux

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Glass vessels, volume 140 mL, diameter 5 cm at the bottom, height 7 cm
- Amount of soil or dung or substrate: 20 g dry weight artificial soil (height of artificial soil layer approximately 1.5 cm)
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8
- No. of replicates per vehicle control: 8

SOURCE AND PROPERTIES OF SUBSTRATE
- Type: Arfticial soil
- Constituents: 75 % fine quartz sand
5% Sphagnum peat, air dried and finely ground
20% Kaolin clay (content of Kaolinite: = 30%)
Calcium carbonate (CaCO3) for the adjustment to pH to 6.0 ±0.5


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Survival of adults and Reproduction after 14 days

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8

EXTRACTION
After a period of 14 days, the surviving adults and the living juveniles were extracted by applying a temperature gradient using a MacFadyen-apparatus. Extracted mites were collected in a fixing solution (20% ethylene glycol, 80% deionised water, 2 g detergent/L fixing solution). All Hypoaspis aculeifer were counted under a binocular.

Nominal and measured concentrations:

0 (Control), 0 (Solvent control), 10, 18, 32, 56, 100 mg test item / kg dry weight artificial soil

Reference substance (positive control):

yes

Remarks:

dimethoate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

32 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

adult mortality

Effect concentrations 2

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

56 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

adult mortality

Effect concentrations 3

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

18 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Effect concentrations 4

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

32 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Effect concentrations 5

Duration:

14 d

Dose descriptor:

EC10

Effect conc.:

33 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Effect concentrations 6

Duration:

14 d

Dose descriptor:

other: EC20

Effect conc.:

43 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Results with reference substance (positive control):

- Adult mortality: LC50 = 3.5 mg dimethoate / kg d.w. artificial soil
- Reproduction: LC50 = 6.7 mg dimethoate / kg d.w. artificial soil

Any other information on results incl. tables

Table 1: Results

mg pure metabolite/kg dry weight artificial soil	adult mortality (%)	Significance (*)	mean number of juveniles per test vessel ± standard dev.	Reproduction (% of solvent control)	significance (**)
Control	3.8	--	357.8 ± 8.7	--	--
Solvent Control	2.5	--	371.4 ± 17.1	--	--
10	2.5	-	366 ± 15.6	98.6	-
18	2.5	-	360.3 ± 13.7	97	-
32	2.5	-	330 ± 22.3	88.9	+
56	30	+	228.8 ± 12.3	61.6	+
100	62.5	+	16.5 ± 7	4.4	+

(*) = Fisher´s exact Binomial Test with Bonferroni Correction, one-sided greater, α=0.05, “-”: non-significant; “+”: significant

(**) = Williams t-test, one sided smaller; α=0.05; “-”: non-significant; “+”: significant

 

Table 2: Validity criteria for OECD 232.

Criterion from the guideline to be satisfied in the controls	Outcome control	Outcome solvent control	Validity criterion fulfilled
Mean adult mortality is≤20 %	7.5 % first test run   2.5 % second test run	12.5 % first test run   5.0 % second test run	Yes
Number of juveniles per replicate (with 10 collembolans introduced) is≥ 100	499 first test run   618 second test run	472 first test run   616 second test run	Yes
Coefficient of variation calculated for the number of juveniles per replicate is≤30 %	17.4 % first test run   23.6 % second test run	15.1 % first test run   17.5 % second test run	Yes

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.