thiacloprid (ISO);(Z)-3-(6-chloro-3-pyridylmethyl)-1,3-thiazolidin-2-ylidenecyanamide;{(2Z)-3-[(6-chloropyridin-3-yl)methyl]-1,3-thiazolidin-2-ylidene}cyanamide

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 Aug - 07 Sep 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 232 (Collembolan Reproduction Test in Soil)

Version / remarks:

2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Application method:

mixed into soil

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil or dung: 50 mL stock solutions containing the test item and artificial water was thoroughly mixed into 500 g artificial dry weight artificial soil of each application rate using a laboratory mixer. The control group was treated first in the same way as described above but with 50 mL deionised water only.
- Controls: deionised water only
- Volume of test solution applied: 50 mL

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

TEST ORGANISM
- Common name: springtail
- Source: laboratory culture (originally obtained from Ibacon, Institute for Analytic and Consulting, Rossdorf, Germany)
- Age at test initiation: 10-12 days
- Kept according to standard practices: yes

Study type:

laboratory study

Limit test:

no

Total exposure duration:

28 d

Test temperature:

20 °C ± 2

pH (if soil or dung study):

5.61 - 5.72

Humidity:

19.27 - 20.35 % water content
47.11 - 50.44 WHCmax

Photoperiod and lighting:

Photoperiod: 16:8 h light:dark (400 - 800 lux)

Details on test conditions:

TEST SYSTEM
- Test container (material, size): glass vessels (volume 140 mL, diameter 5 cm, height 7 cm)
- Amount of soil or dung or substrate: 30 g ww
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8

SOURCE AND PROPERTIES OF SUBSTRATE
- Soil texture (if natural soil)
- % sand:
- % silt:
- % clay:
- Soil taxonomic classification:
- Soil classification system:
- Composition (if artificial substrate): 74.8 % fine quartz sand (sort F 36, particle size 0.2 – 0.05 mm = 91.35 %), - 5 % Sphagnum peat, air dried and finely ground, 20 % Kaolin clay (content of Kaolinite: Al2Si2O5(OH)4) = 30.2 %), approximately 0.2 % Calcium carbonate (CaCO3)
- Maximum water holding capacity (in % dry weight): 50.67%

OTHER TEST CONDITIONS
- Photoperiod: 16:8 h light:dark
- Light intensity: 400 - 800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : surviving adults and living juveniles (after 28 d)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 1.78
- Range finding study
- Test concentrations: 0.44, 2.22, 4.42, 44.24, 442.48 and 4424.78 mg test item/kg soil dw
- Results used to determine the conditions for the definitive study: LC50 = 4.42 - 44.24 mg test item/kg soil dw

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 4.4, 7.9, 14.0, 24.9 and 44.3 mg test item/kg soil dw (≙ 1.0, 1.8, 3.2, 5.6 and 10 mg a.i./kg soil dw)

Reference substance (positive control):

yes

Remarks:

Boric acid

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

3.16 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Remarks on result:

other: Recalculated based on test item purity of 22.6%

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

3.6 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Remarks on result:

other: Recalculated based on test item purity of 22.6%

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

14 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

15.9 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95 % C.I.: 8.4 - 20.2 mg test item/kg soil dw

Details on results:

- Mortality at end of exposure period: control: 9% treatment group: 20 - 50%

Results with reference substance (positive control):

- Results with reference substance valid? yes
The result is in the recommended range of the guideline (about 100 mg Boric acid/kg artificial soil dry weight)
- Relevant effect levels: EC50 = 91 mg/kg soil dw
- Other: NOECreproduction = 44 mg/kg soil dw

Reported statistics and error estimates:

The software used to perform the statistical analysis was ToxRat Professional 2.10 released February 20, 2010, (Ratte, 2010). Data of reproduction were tested for normal distribution and homogeneity of variance using Kolmogorov - Smirnov -Test and Cochran’s -Test (α = 0.05) respectively. Data of reproduction were normally distributed and homogeneity of variances was given. Therefore William's-t test (one-sided-smaller, α = 0.05) was used to determine NOEC and LOEC values. The LC10, 20, 50 values were determined by Probit analysis.

Table 1: Survival of adult collembolans after 4 weeeks (n=10/replicate)

	mg test item (mg a.i.)/kg artificial soil dry weight
Replicates 1)	Control	4.4 (1.0)	7.9 (1.8)	14.0 (3.2)	24.9 (5.6)	44.3 (10.0)
1	10	10	6	8	7	7
2	9	7	3	9	7	5
3	8	7	5	7	7	7
4	9	8	6	5	7	5
5	9
6	10
7	10
8	8
Mean 2)	9.1	8.0	5.0	7.3	7.0	6.0
SD 2)	0.8	1.4	1.4	1.7	0.0	1.2
% Mortality 3)	8.8	20.0	50.0	27.5	30.0	40.0

Calculations were done with un-rounded values.

¹surviving adult/replicate, each vessel contained a total of 10 collembolans at the test start

²mean and standard deviation (SD) of 8 replicates of the control group and 4 replicates for the treatment groups

³formula: ((initial placed organisms per vessel – mean of surviving adults per vessel) / 10) * 100

Table 2: Reproduction of the collembolans after 4 weeks treatment (juveniles/replicate)

	mg test item (mg a.i.)/kg artificial soil dry weight
Replicates1)	Control	4.4 (1.0)	7.9 (1.8)	14.0 (3.2)	24.9 (5.6)	44.3 (10.0)
1	1173	1202	1603	1315	895	183
2	1340	1146	1329	1372	1077	274
3	1383	1280	1539	1326	805	227
4	1539	1509	1216	1225	771	277
5	1409
6	1435
7	1490
8	1505
Mean2)	1409.3	1284.3	1421.8	1309.5	887.0	240.3
SD2)	116.2	159.6	180.3	61.5	137.0	44.5
CV3)	8.2
% of Control4)	-	91.1	100.9	92.9	62.9	17.0
Statistics	-	n.s.	n.s.	n.s.	*	*

Calculations were done with un-rounded values

1 juveniles produced per test vessel, each test vessel contained a total of 10 collembolans at the test start

2 mean and standard deviation (SD) of 8 replicates of the control group and 4 replicates for the

treatment groups

3 Coefficient of variation

4 formula: mean number of juveniles per treatment group * 100 / mean number of juveniles per control group

-          = not applicable

*         = significantly different compared to the control (William's T-test, one-sided-smaller, α = 0.05)

n.s. = not significantly different compared to the control (William's T-test, one-sided-smaller, α = 0.05)

Table 3: Validity criteria for OECD 232

Criterion from the guideline	Outcome	Validity criterion fulfilled
Mean adult mortality should not exceed 20% at the end of the test	8.8%	yes
The mean number of juveniles per vessel should be at least 100 at the end of the test	1173 - 1539	yes
The coefficient of variation calculated for the number of juveniles should be less than 30% at the end of the definitive test.	8.2	yes

Validity criteria fulfilled:

yes

Remarks:

For further, details, please refer to 'Any other information on results incl. tables'.

Conclusions:

The EC10 (28 d) was determined to be 15.9 mg test item /kg soil dw, corresponding to 3.6 mg a.i./kg soil dw (nominal) in a collembolan reproduction test with Folsomia candida (OECD 232).

Reference 2

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

05 - 29 Aug 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

yes

Remarks:

15 days of exposition instead of 14 days. This deviation have no impact on the outcome of the study.

GLP compliance:

yes (incl. QA statement)

Application method:

mixed into soil

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Hypoaspis aculeifer

Animal group:

Acari (soil-dwelling predatory mite)

Study type:

laboratory study

Limit test:

no

Total exposure duration:

15 d

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 100, 178, 316, 562 and 1000 mg test item/kg soil dw

Reference substance (positive control):

yes

Remarks:

dimethoate

Toxic reference:

LC50 = 4.051 mg a.i./kg soil dw
NOECreproduction = 3.156 mg a.i./kg soil dw

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

71.4 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Remarks on result:

other: Recalculated based on test item purity of 22.6%

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

316 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

15 d

Dose descriptor:

LC50

Effect conc.:

226 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: Recalculated based on test item purity of 22.6%

Duration:

15 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Validity criteria fulfilled:

yes

Conclusions:

The NOEC (15 d) was determined to be 316 mg test item/kg soil dw, corresponding to 71.4 mg a.i./kg soil dw (nominal) in an reproduction test in soil with predatory mite Hypoaspis aculeifer (OECD 226).

Description of key information

NOEC (28 d) = 3.16 mg/kg soil dw (nominal, Folsomia candida, OECD 232)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil dwelling arthropods:

3.16 mg/kg soil dw

Additional information

Several studies are available assessing the toxicity of 3-(2-chlor-5-pyridyl-methyl)-cyanimino-1,3-thiazolidin to terrestrial arthropods.

In the key study, 10 organisms of Folsomia candida (10 - 12 days old) per replicate (8 replicates for the control group and 4 replicates for each treatment group) were exposed to control (water treated), and 4.4, 7.9, 14.0, 24.9 and 44.3 mg test item/kg soil dw (corresponding to 1.0, 1.8, 3.2, 5.6, and 10 mg a.i./kg soil dw) according to OECD 232. Mortality and reproduction were determined after 28 days. In the control group mortality was 8.8 %. A mortality of 50 % was observed in the treatment group with 7.9 mg test item/kg soil dw but is not considered test item related since mortality was lower in the higher treatment groups. The NOEC (28 d ) for reproduction was determined to be 14.0 mg test item/kg soil dw corresponding to 3.16 mg a.i./kg soil dw (nominal, recalculated based on test item purity).

A further study with soil dwelling organisms is supporting this result. The study was performed with predatory mite (Hypoaspis aculeifer) according OECD 226. Female mites were exposed to control and treatments concentrations of between 100 and 1000 mg test item/kg soil dw for 15 days. The derived NOEC (15 d) was determined to be 316 mg test item/kg soil dw, corresponding to 71.4 mg a.i./kg soil dw (nominal).

In addition, several studies assessing the toxicity of 3-(2-chlor-5-pyridyl-methyl)-cyanimino-1,3-thiazolidin on bees are available.

In a study performed according to EPPO guideline No. 170 and Apis mellifera, the oral LD50 (10 d) was determined to be 17.32 µg/bee and the contact LD50 (10 d) was obtained to be 38.82 µg/bee.

Another study determined the toxixity of the target substance according to the OECD Draft Test Guideline on Honey Bee (Apis mellifera) Larval Toxicity Test in first instar larvae of A. mellifera. The No Observed Effect Dose (NOED, 4 d) determined in this in vitro honey bee larvae study was 1.78 µg a.i./larva and the LD50 (4 d) was determined to be > 5.34 µg a.i./larva.

Two further studies determined the chronic effects of the target substance on adult honey bee A. mellifera L., in 10 days continuous feedings test in the laboratory. In the first study, the NOEC (10 d) for lethal effects was determined to be 29 mg a.i./kg. The LC50 (10 d) was calculated to be 50.9 mg a.i./kg diet. In the second study the NOEC (10 d) was 10000 µg a.i./L at the end of the test period, which is equivalent to a NOEC (10 d) of 8130 µg a.i./kg diet. Based on the amount of food consumed this equates to a NOED (mortality) of ≥ 0.37 µg a.i./bee/day.