mancozeb (ISO); manganese ethylenebis(dithiocarbamate) (polymeric) complex with zinc salt  

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to non-target arthropods on inert substrate (NTA other than pollinators)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005-11-30 to 2005-01-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Please refer to section "Principles of method if other than guideline".

Qualifier:

according to guideline

Guideline:

other: Meeting on coordination of activities in soil mite testing, Bayer Monheim, Germany (Bakker et al., December 2003)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: Guidance document on regulatory testing and risk assessment procedures for plant protection products with non-target arthropods (Candolfi et al., 2001)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

A laboratory test protocol to evaluate effects of plant protection products on mortality and reproduction of the predatory mite Hypoaspis aculeifer Canestrini (Acari: Laelapidae) in standard soil (Bakker et al., 2003)

Deviations:

not specified

Principles of method if other than guideline:

This study is quite similar to OECD 226 guideline, but differs from the guideline in some ways. Two day old protonymphs were used instead of 28-35 day old adult females, the study duration was 21 days rather than 14 days, the protonymphs were exposed to the contaminated soil for 1.5 hours and then transferred onto a glass plate test system, rather than staying on the soil for the whole duration of the study. These differences should be considered in the context of the risk assessment.

GLP compliance:

yes

Application method:

mixed into substrate

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Water

Details on preparation and application of test substrate:

The test product was stored at room temperature in the dark and all use was registered.

All solutions were prepared with calibrated precision laboratory equipment less than 45 minutes before application. Deionised water was used as solvent for all solutions. The test solutions were prepared as follows:

Dithane M-45:
A stock was obtained by dissolving 0.5005 g product in deionised water up to a total volume of 1000 ml. The final Solutions were obtained as follows:
1.1 mg a.i./kg soil: 1.05 ml stock in deionised water up to a total volume of 100 mL.
2.1 mg a.i./kg soil: 2.05 ml stock in deionised water up to a total volume of 100 mL.
4.3 mg a.i./kg soil: 4.15 ml stock in deionised water up to a total volume of 100 mL.

Toxic reference:
A stock was obtained by dissolving 1.0 mL product in deionised water up to a total volume of 100 mL. The final Solution was obtained by dissolving 1.2 mL stock in deionised water up to a total volume of 100 mL.

Test organisms (species):

Hypoaspis aculeifer

Animal group:

Acari (soil-dwelling predatory mite)

Details on test organisms:

- Species: Hypoaspis aculeifer (Acari: Laelapidae)
- Age at test initiation: < 2 day old protonymphs
- Source: from stock culture at test facility
- Feeding: Tyrophagus putrescentiae as prey

Study type:

laboratory study

Limit test:

no

Total exposure duration:

21 d

Test temperature:

mortality phase: Mean 22.5°C;
reproduction phase: Mean 22.8°C

pH (if soil or dung study):

not specified

Humidity:

65 ± 15%

Photoperiod and lighting:

held in dark

Details on test conditions:

TEST SYSTEM
- Test container:
Mortality phase: Munger cells (EPPO Guideline 142, 1989)
Mating and reproduction phase: Plastic urtits with humidrfied carbon-darkened untreated plaster
- Cohort: Climate box operated at 20 + 2°C, 65 ± 1 5% RH and in the dark (as dark as practically feasible)
- No. of organisms per container (treatment): 20 protonymphs per Munger unit
- No. of replicates per treatment group: 5
- No. of replicates per control: 5
- No. of replicates reference control: 3

SOURCE AND PROPERTIES OF SUBSTRATE: standard soil (OECD, 10% sphagnum), not further specified

OTHER TEST CONDITIONS
- Photoperiod: no photoperiod, 24 h darkness


EFFECT PARAMETERS MEASURED:
- Mortality/escape rate observed after a 21-day exposure period
- Reproduction (fertile eggs/female/7 days) over a 7-day period for surviving females in the deionised water control and the 3 test item rates causing a corrected mortality >50%

VEHICLE CONTROL PERFORMED: yes (with deionised water)

Nominal and measured concentrations:

Nominal: 1.1, 2.1 and 4.3 mg a.s./kg dry soil (1.3, 2.6, and 5.2 mg product/kg dry soil); no measured concentrations

Reference substance (positive control):

yes

Remarks:

Perfektion (dimethoate 400 g/L EC); rate: 12 mg a.s./kg dry soil

Toxic reference:

reference control performed with dimethoate

Key result

Duration:

21 d

Dose descriptor:

ER50

Effect conc.:

> 4.3 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

LR50

Effect conc.:

> 4.3 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

2.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The mean measured temperature throughout the mortality phase was 22.5ºC (Standard Deviation: 1.8) and 22.8ºC (SD: 1.8) in the reproduction phase. Mean measured relative humidity during the mortality phase was 67.9% (SD: 7.0) and 69.1% (SD: 6.3) in the reproduction phase.

Mortality was classed as the difference between the number of living mites found at the end of the study and the initial number of mites introduced (i.e. mortality included dead and escaped mites). After the 21 day exposure period, the mortality in the control was 14%. The corrected mortality in the test treatments was 3, 7, and 15% in the 1.1, 2.1 and 4.3 mg a.s./kg dry soil treatments respectively. Only the mortality in the 4.3 mg a.s./kg dry soil treatment was statistically significantly higher (27% uncorrected) than the control. There was an observable dose-response relationship between dosing rate of Dithane M-45 and mortality. The LC50 was determined to be > 4.3 mg a.s./kg dry soil. The toxic reference mortality was 67% (corrected).

Only reproduction data of females retrieved alive after 7 days were included in the analysis. The number of fertile eggs produced per female after 7 days was 17.9, 13.9, 13.8, and 13.5 in the control, and in the 1.1, 2.1, and 4.3 mg a.s./kg dry soil treatments, respectively. None of the test treatment concentrations produced statistically significant drops in reproductive output. The ER50 was determined to be > 4.3 mg a.s./kg dry soil.

Results with reference substance (positive control):

The toxic reference , dimethoate, caused 67% corrected mortality. This showed that the test animals were sufficiently sensitive and potential adverse effects of exposure to test item residues could be detected with the set-up used in this experiment.

Reported statistics and error estimates:

Mortality in the treatment groups was compared pair-wise to the water control using Fisher’s Exact Test. Egg production was compared to the water control using the Mann-Whitney U test.

Validity criteria fulfilled:

yes

Remarks:

This study adhered to the validity criteria presented in the OECD guideline. The adult mean mortality in the control treatment did not exceed 20%. The mortality in the toxic reference substance was >50%. Females in the control produced > 5 offspring each.

Conclusions:

The LR50 of Hypoaspis aculeifer determined in this study was > 4.3 mg a.s./kg dry soil (equivalent to LR50 > 3200 g a.s./ha). Based on reproduction, the ER50 was > 4.3 mg a.s./kg soil dw (equivalent to ER50 > 3200 g a.s./ha). The endpoint for consideration in the risk assessment is NOEC mortality = 2.1 mg/kg soil dw.

Executive summary:

The toxicity of the Dithane M-45 (active ingredient Mancozeb, purity: 82.3%) to Hypoaspis aculeifer was assessed in a GLP-compliant study similar to OECD TG 226. The test design differed from the guideline by the following: Two day old protonymphs were used instead of 28-35 day old adult females, the study duration was 21 days rather than 14 days, the protonymphs were exposed to the contaminated soil for 1.5 hours and then transferred onto a glass plate test system, rather than staying on the soil for the whole duration of the study. Solutions of the test item were mixed homogeneously through standard soil (OECD) to give 3 nominal rates, viz. 1.1, 2.1 and 4.3 mg a.i./kg dry soil. The control was treated with deionised water. Dimethoate at a rate of 12 mg a.i./kg dry soil was used as toxic reference. The bioassay was initiated within 1.5 hours after application by confining 20 protonymphs of Hypoaspis aculeifer per Munger unit (inert glass material). Five units were prepared for the water control, 5 units for each test rate of the test item and 3 units for the toxic reference. During the mortality phase, food and water were provided on days 3, 6, 8, 10, 13, 15, and 17. Status of the mites was assessed on day 21 (number of live adults, corpses, and occurrence of offspring). During the reproduction phase, the numbers of juveniles and eggs were counted 5-6 days after the removal of the females after the 7 day laying period. Climatic conditions were measured with a data logger at 15 minute intervals. Control mortality (14%) and reproductive performance (17.9 fertile eggs/female/7 days) in the control treatment met the validation criteria of the study and indicated that test animals were in good condition. The toxic reference, dimethoate, caused 67% corrected mortality. This showed that test animals were sufficiently sensitive and that potential adverse effects of exposure to test item residues could be detected with the set-up used in this experiment. The LR50 of Hypoaspis aculeifer determined in this study was > 4.3 mg a.s./kg dry soil (equivalent to LR50 > 3200 g a.s./ha). Based on reproduction, the ER50 was > 4.3 mg a.s./kg soil dw (equivalent to ER50 > 3200 g a.s./ha). The endpoint for consideration in the risk assessment is NOEC mortality = 2.1 mg/kg soil dw.

Description of key information

Short-term toxicity to terrestrial arthropods

In accordance with REACH Annex XI a short-term study does not need to be conducted because an appropriate long-term toxicity study on terrestrial arthropods is available. Additional data on short-term toxicity is scientifically not necessary.

Short-term toxicity to terrestrial arthropods

The long-term toxicity to terrestrial arthropods was assessed in a study with Hypoaspis aculeifer similar to OECD TG 225. The 21-day LR50 was determined to be > 4.3 mg a.s./kg dry soil (equivalent to LR50 > 3200 g a.s./ha). Based on reproduction, the ER50 was > 4.3 mg a.s./kg soil dw (equivalent to ER50 > 3200 g a.s./ha). The endpoint for consideration in the risk assessment is NOEC mortality = 2.1 mg/kg soil dw.

Key value for chemical safety assessment

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

2.1 mg/kg soil dw

Additional information

Key information

Dithane M-45: An extended laboratory limit test to evaluate the effects on survival and reproduction of the predaceous mite Hypoaspis aculeifer Canestrini (Acari: Laelapidae) in artificial soil (OECD) (Loose  2005 ( Doc. No. 835-001, cross reference to Risk Assessment Report according to Regulation (EU) No 1107/2009: 0.3.2.2/09))

The toxicity of the Dithane M-45 (active ingredient Mancozeb, purity: 82.3%) to Hypoaspis aculeifer was assessed in a GLP-compliant study similar to OECD TG 226 (Loose, 2005). The test design differed from the guideline by the following: two day old protonymphs were used instead of 28-35 day old adult females, the study duration was 21 days rather than 14 days, the protonymphs were exposed to the contaminated soil for 1.5 hours and then transferred onto a glass plate test system, rather than staying on the soil for the whole duration of the study. Solutions of the test item were mixed homogeneously through standard soil (OECD) to give 3 nominal rates, viz. 1.1, 2.1 and 4.3 mg a.s./kg dry soil. The control was treated with deionised water. Dimethoate at a rate of 12 mg a.s./kg dry soil was used as toxic reference. The bioassay was initiated within 1.5 hours after application by confining 20 protonymphs of Hypoaspis aculeifer per Munger unit (inert glass material). Five units were prepared for the water control, 5 units for each test rate of the test item and 3 units for the toxic reference. During the mortality phase, food and water were provided on days 3, 6, 8, 10, 13, 15, and 17. Status of the mites was assessed on day 21 (number of live adults, corpses, and occurrence of offspring). During the reproduction phase, the numbers of juveniles and eggs were counted 5-6 days after the removal of the females after the 7 day laying period. Climatic conditions were measured with a data logger at 15 minute intervals. Control mortality (14 %) and reproductive performance (17.9 fertile eggs/female/7 days) in the control treatment met the validation criteria of the study and indicated that test animals were in good condition. The toxic reference, dimethoate, caused 67% corrected mortality. This showed that test animals were sufficiently sensitive and that potential adverse effects of exposure to test item residues could be detected with the set-up used in this experiment. The LR50 of Hypoaspis aculeifer determined in this study was > 4.3 mg a.s./kg dry soil (equivalent to LR50 > 3200 g a.s./ha). Based on reproduction, the ER50 was > 4.3 mg a.s./kg soil dw (equivalent to ER50 > 3200 g a.s./ha). The endpoint for consideration in the risk assessment is NOEC mortality = 2.1 a.s. mg/kg soil dw.