clothianidin (ISO); (E)-1-(2-chloro-1,3-thiazol-5-ylmethyl)-3-methyl-2-nitroguanidine

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:

key study

Study period:

10 Apr - 09 Jun, 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium fur Umwelt, landlichen Raum und Verbraucherschutz, delivered on 22 Nov, 2005

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

A stock solution was prepared by weighing 100 mg of Clothianidin FS 600B G and deionised water was added to reach a final net weight of 360 g. The resulting suspension contained a concentration of 0.2778 mg test item/g. A dilution was prepared by adding 950 g deionised water to 50 g of the stock solution (concentration of 0.01389 mg test item/g). 354.2 g of this stock solution were added to artificial soil equivalent to 2050 g dry weight resulting in the nominal concentration of 2.40 mg test item/kg soil dry weight.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

Adults, with well developed clitellum, age range between test individuals not differing by more than 4 weeks (approximately 11 months).
Weight: 304 mg - 582 mg
Source: Bred under standardised conditions (in a breeding medium of cattle manure, peat, sand and straw, fed with cattle manure, stored at room temperature) by IBACON
Acclimatisation: 1 day, in artificial soil, under test conditions

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

56 d

Test temperature:

19 - 21°C

pH:

6.4 - 6.0

Moisture:

50.4% to 56.8% (varies less than 10% throughout the study duration)

Details on test conditions:

Plastic boxes (18.3 cm x 13.6 cm x 6 cm, tapered towards the bottom, with the soil surface of approximately 16.5 cm x 11.5 cm = 189.75 cm2) with perforated transparent lids to enable exchange of air, to minimise evaporation from the artificial soil, and to prevent the worms from escaping. Each container was filled with 668.1 g of the prepared soil. The height of the soil layer in the containers was approximately 5 cm.
Test substrate according to OECD 207.
Light: 16h light : 8h dark
Feeding: Fine ground cattle manure was used as food. 10 g/kg dry soil was mixed into the artificial soil at study start; 5 g/container was scattered on the soil surface at day 1 after application and was moistened with 5 - 6 g deionised water; 5 g/container (moistened with 5 - 6 g deionised water) was added each week for the first 4 weeks of the experiment.

Nominal and measured concentrations:

Nominal: 1.15 mg a.s/kg (corresponding to 2.40 mg test item/kg)

Reference substance (positive control):

yes

Remarks:

most recent study with: Brabant Carbendazim Flowable (500g/L)

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

< 2.4 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: equivalent to < 1.15 mg a.s./kg s.d.w.

Details on results:

In this study the no-observedeffect-concentration (NOEC) for mortality, growth, and feeding activity was determined to be 2.40 mg test item/kg soil dry weight, i.e. the highest concentration tested. The NOEC for reproduction was determined to be lower than 2.40 mg test item/kg soil dry weight.

Results with reference substance (positive control):

In the most recent test with the reference item Brabant Carbendazim Flowable (from December 2007 to February 2008), there were statistically significant effects on reproduction at a concentration of 1.7 mg carbendazim/kg soil dry weight; the EC50 for reproduction was calculated as 1.48 mg carbendazim/kg soil dry weight.

Please refer to "overall remark/ attached background material" field for result tables.

Table 1: Validity criteria for OECD 222 (2016)

Criterion from the guideline to be satisfied in the controls	Outcome	Validity criterion fulfilled
Adult mortality over the initial 4 weeks of the test is ≤ 10%.	0 %	Yes
Each replicate (containing 10 adults) to have produced ≥ 30 juveniles by the end of the test.	At least 150 juveniles per replicate	Yes
The coefficient of variation of reproduction is ≤ 30%.	20.2%	Yes

Validity criteria fulfilled:

yes

Remarks:

according to the report and the current OECD guideline. For further details please refer to “Any other information on results incl. tables”.

Conclusions:

The present guideline study was conducted in compliance with GLP. Under the test conditions used, the NOEC 56d for Eisenia fetida was < 1.15 mg a.s./kg dry weight soil.

Description of key information

The overall long-term NOEC for the soil macroorganisms except arthropods (Eisenia fetida) is <1.15 mg a.s./kg dry weight soil.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

13.21 mg/kg soil dw

Additional information

Two GLP-studies are available for toxicity testing to soil macroorganisms except arthropods and one of them was identified as key study.

 

In the key study (2008), the chronic toxicity of test susbtance to earthworms (Eisenia fetida) was investigated after 56-day exposure according to OECD 222 guideline. Ten earthworms, in each of the height replicates, were exposed to a concentration of 2.4 mg test substance /kg soil dry weight (equivalent to 1.15 mg a.s./kg s.d.w.), alongside with a control. The reproduction NOEC was determined to be < 1.15 mg a.s./kg soil d.w., the highest concentration tested.

 

A supportive study according to OECD 207 was performed with Eisenia fetida as test organism. In this test, the LC₅₀(14-d) was 13.21 mg test substance/kg s.d.w.