Captan

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:

6 October 2011 to 9 December 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:

OECD (2009)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Application method:

mixed into soil

Specific details on test material used for the study:

- Name of test material: Merpan 80 WDG
- Active ingredient: Captan, N-(trichloromethylthio)cyclohex-4-ene-1,2-dicarboximide
- Appearance: off-white extruded granule
- Physical state: White crystalline solid
- Nominal content of a.i.: 80.8% (w/w)
- Measured content a.i.: 80.8% w/w
- Batch number: 91131140
- Sample expiry date: 3 June 2013

Analytical monitoring:

no

Details on sampling:

- Concentrations: Merpan 80 WDG (batch 91131140, measured
purity of a.i. = 80.8% w/w) was evaluated in a definitive test at five concentrations,
equivalent to 1000, 562.4, 316.3, 177.9 and 100.1 mg a.i./kg soil dry weight
- Sampling method: At 28 days the numbers of the original
springtails still surviving and the numbers of offspring they had produced were
recorded.

Vehicle:

yes

Remarks:

The test item and toxic reference treatment were diluted in purified water and then sufficient amounts of these solutions were added to the artificial soil.

Details on preparation and application of test substrate:

- Method of mixing into soil: For each treatment
concentration, 18 mL of the appropriate solution was thoroughly mixed with 220.43 g of pre-moistened artificial test soil (equivalent to 200 g dry soil), to achieve a final soil moisture content equivalent to 50% of the soil’s pre-determined maximum waterholding capacity (WHC) The test item and toxic reference treatment were diluted in purified water and then sufficient amounts of these solutions were added to the artificial soil to reach a 50% WHC. For the control treatment, purified water only (sufficient to make the soil up to 50% WHC) was added to the substrate. Once the treatments had been fully mixed in, the soil had a naturally crumbly structure, which allowed the springtails to migrate into the substrate. Volume of test solution applied: 18 mL

- Chemical name of vehicle: purified water

- Control: In the definitive bioassay the control treatment, 27 mL of purified water was thoroughly mixed with 330.64 g of pre-moistened artificial test soil (equivalent to 300 g dry soil). This gave a final moisture content 50% of the soil’s WHC. The soil had been previously been moistened to approximately 25% of its WHC

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

TEST ORGANISM
- Common name: Folsomia candida (Collembola, Isotomidae)
- Source: Syngenta Ltd., Jealott’s Hill International Research
Centre, Bracknell, UK
- Age at test initiation: 10-day-old
- The pH of the spare soil was measured (in the presence of 1 mol/L KCl) at
the start of the test, according to ISO 10390 (ISO, 1994).

Study type:

laboratory study

Remarks:

The aim of the test was to determine under laboratory test conditions whether this test item had harmful effects on the springtail Folsomia candida (Willem) (Collembola, Isotomidae).

Limit test:

yes

Total exposure duration:

28 d

Test temperature:

- rangefinding test: 19.4-22.4ºC
- definitive test: 20.2-21.8ºC

pH (if soil or dung study):

between 6 ± 0.5

Humidity:

- rangefinding test: 19-86% relative humidity (RH)
- definitive test: 54-60% relative humidity (RH)

Photoperiod and lighting:

- rangefinding test: 16 h photoperiod of 560-620 lux
- definitive test: 16 h photoperiod of 560-620 lux.

Details on test conditions:

TEST SYSTEM
- Test container (material, size): were glass jars (approximately 125 mL capacity and 4.5 cm in diameter), secured with a close-fitting lid.
- Amount of soil: 30 g of the soil was transferred into each replicate glass jar.
- No. of organisms per container (treatment): ten juvenile springtails (10 days old)
SOURCE AND PROPERTIES OF SUBSTRATE (if soil or dung)
The test substrate was an artificial soil comprising the following dry-mass fractions, which were thoroughly integrated by mixing:
• 5% w/w moss peat (Sphagnum Peat; Westland Horticulture, Dungannon,
Ireland), air-dried, finely ground and with no visible plants remaining.
• 20% w/w kaolinite clay (Puraflo, Sandbach, UK), air-dried, containing not less
than 30% kaolinite.
• 74.85% w/w industrial quartz sand (Silver Sand; J. Arthur Bowers, UK), airdried,
predominately fine sand with > 50% particle 0.05-0.2 mm.
• 0.15% w/w calcium carbonate (CaCO3) (Acros Organicss, UK), pulverized and
of recognisable analytical grade (to bring the soil pH (as measured in 1 mol/L
KCl solution) to between 6 ± 0.5).
VEHICLE CONTROL PERFORMED: yes
TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: five concentrations, equivalent to 1000, 562.4, 316.3, 177.9 and 100.1 mg a.i./kg soil dry weight

Nominal and measured concentrations:

An initial range-finding test was carried out using concentrations equivalent to 1000, 100, 10, 1 and 0.1 mg a.i./kg soil dry weight (based on measured a.i. content).
A definitive test was carried out, in which the test item was evaluated at five
concentrations, equivalent to 1000, 562.4, 316.3, 177.9, and 100.1 mg a.i./kg dry
weight soil (based on measured a.i. content).

Reference substance (positive control):

yes

Toxic reference:

In the toxic reference treatment, 74% mortality (74% corrected mortality) was
recorded.

Key result

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

316.3 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

177.9 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

807.9 mg/kg soil dw

95% CI:

648.3 - 1 103.6

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Results with reference substance (positive control):

- Results with reference substance valid? yes

The results of the reproduction assessments during the definitive test are summarised in Table 2. In the control, the mean number of progeny produced per replicate was 550 compared with 228, 354, 412, 493, and 520 in the 1000, 562.4, 316.3, 177.9, and 100.1 mg a.i./kg soil treatment concentrations of Merpan 80 WDG, respectively. Statistically, the results for the 1000, 562.4 and 316.3 mg a.i./kg soil treatment concentrations differed significantly from the control (ANOVA, α = 0.05). Based on these results, the NOEC was 177.9 mg a.i./kg soil and the LOEC was 316.3 mg a.i./kg soil.

Table 2. The number of progeny produced by 28 DAT in the definitive test. The percentage reduction in the reproductive performances of each treated group compared to the control group is also given

Treatment	Concentration (mg a.i./kg soil)	Mean no. progeny per replicate ^a)	% change relative to the control ^b)
Control	-	550	-
Merpan 80 WDG	1000	228***	58.5
	562.4	354***	35.6
	316.3	412***	25.1
	177.9	493	10.4
	100.1	520	5.5
Toxic reference	-	76***	86.2

1. The results for each treatment were individually compared to the control by one-way ANOVA and Dunnett’s t-test (α = 0.05). Values marked with asterisks differed significantly from the (*** P < 0.001).


2. A positive value indicates a decrease in reproduction, relative to the control.

Validity criteria fulfilled:

yes

Conclusions:

In a laboratory test to evaluate the effects of Merpan 80 WDG on the springtail Folsomia candida, the LC50 (median lethal concentration) was > 1000 mg a.i./kg soil dry weight, the maximum concentration tested. With respect to their progeny, the 28-day EC50 (median effect concentration) was 807.9 mg a.i./kg soil (95% confidence limits = 648.3 and 1103.6 mg a.i./kg soil). Based on statistical comparisons, the NOEC for effects on reproduction was 177.9 mg a.i./kg soil dry weight and the LOEC was 316.3 mg a.i./kg soil dry weight.

Executive summary:

The test item in this study was Merpan 80 WDG, a water-dispersible granule formulation containing the active ingredient captan (nominally 80% w/w). The aim of this study was to determine under laboratory test conditions whether this test item had harmful effects on the springtail Folsomia candida (Willem) (Collembola, Isotomidae). This is considered to be a suitable test species for determining the effects of pesticides on soil-active Collembola in the agricultural ecosystem (Wiles et al., 1998). The test design was in line with current European guidance documents (Barrett et al., 1994; Candolfi et al., 2001), that themselves meet the requirements of EU Commission Directive 96/12/EC (1996). The test method was based on OECD laboratory test guideline 232 (OECD, 2009), which supersedes ISO guideline 11267 (1999). This involved the confinement of
springtails in an artificial soil substrate containing 5% peat, following its treatment with the test item. The survival and reproduction of the springtails was then assessed
over a period of 28 days.

An initial range-finding test was carried out using concentrations equivalent to 1000, 100, 10, 1 and 0.1 mg a.i./kg soil dry weight (based on measured a.i. content).
A definitive test was carried out, in which the test item was evaluated at five concentrations, equivalent to 1000, 562.4, 316.3, 177.9, and 100.1 mg a.i./kg dry weight soil (based on measured a.i. content).

Control = purified water
In the Control, 1% mortality (0% corrected mortality) was recorded.

Toxic reference item = Betosip 114 (Sipcam)
In the toxic reference treatment, 74% mortality (74% corrected mortality) was recorded.

In the control, the mean number of progeny produced per replicate was 550 compared with 228, 354, 412, 493, and 520 in the 1000, 562.4, 316.3, 177.9, and 100.1 mg a.i./kg soil treatment concentrations of Merpan 80 WDG, respectively. Statistically, the results for the 1000, 562.4 and 316.3 mg a.i./kg soil treatment concentrations differed significantly from the control (ANOVA, α = 0.05). Based on these results, the NOEC was 177.9 mg a.i./kg soil and the LOEC was 316.3 mg a.i./kg soil.

Reference 2

Endpoint:

toxicity to bees: acute oral

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

19 July to 3 August 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

GLP - Guideline study The experiments were done according to the UK MAFF PSPS Working Document D3 (1979).

Qualifier:

according to guideline

Guideline:

other: UK MAFF PSPS Working Document D3 (1979)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.16 (Honeybees - Acute Oral Toxicity Test)

GLP compliance:

yes

Application method:

other: contact and oral

Specific details on test material used for the study:

Technical Captan
- Physical state: white powder
- Analytical purity: 98.1% (w/w),
- Batch number: WRC 12035-30-1

Analytical monitoring:

no

Details on sampling:

A range of dose rates and a control were used for each test, with three replicate cages of 10 bees per dose rate. Mortality and sublethal effects were assessed at 1, 4, 24 and 48 hours after treatment. Effects were also assessed at 2 hours after treatment in the rangefinder tests but not in definitive tests because effects were not present at the interval in the former.

Oral Test:
Each group of 10 bees was offered 0.2 ml of a given concentration. Dose consumed: 0.1, 1, 2, 5, 10, 20, 50, 100 µg ai bee-1. Technical captan dissolved in acetone in 50% sucrose solution.
Contol: Contol bees were given 50% sucrose soluttion containing 5% v/v acetone.
Positive Control: Oral toxicity was tested with Dimethoate as Toxic Standard: 0.075, 0.15, 0.3 µg ai bee-1.

Contact Test:
Two 1 µL drops /bee of technical captan in chloroform was applied to the thorax at following dose ranges: 0.1, 1, 5, 10, 20 µg captan/bee.
- Sampling method:
Mortality and sublethal effects were assessed one, four, 24 and 48 hours after treatment.
Control: Control bees were treated with acetone.
Positive Contol: Contact toxicity was tested with Dimethoate as Toxic Standard: 0.075, 0.15, 0.3 µg ai bee-1.

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Apis mellifera

Animal group:

Hymenoptera (honeybees)

Study type:

laboratory study

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

22.5 - 24° C

Humidity:

56 - 68% relative humidity

Reference substance (positive control):

yes

Remarks:

Technical dimethoate; - Analytical purity: 98.4 w/w - Batch number: ASY/282

Key result

Duration:

24 h

Dose descriptor:

LD50

Effect conc.:

> 100 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

oral

Remarks on result:

other: 0.154 - 0.218 % CL

Key result

Duration:

48 h

Dose descriptor:

LD50

Effect conc.:

> 100 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

oral

Remarks on result:

other: 0.142 - 0.206 % CL

Key result

Duration:

24 h

Dose descriptor:

other: NOEL

Effect conc.:

>= 100 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

oral

Key result

Duration:

48 h

Dose descriptor:

other: NOEL

Effect conc.:

>= 100 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

oral

Key result

Duration:

24 h

Dose descriptor:

LD50

Effect conc.:

> 200 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

contact

Remarks on result:

other: 0.166 - 0.215 % CL

Key result

Duration:

48 h

Dose descriptor:

LD50

Effect conc.:

> 200 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

contact

Remarks on result:

other: 0.150 - 0.199 % CL

Key result

Duration:

24 h

Dose descriptor:

other: NOEL

Effect conc.:

>= 200 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

contact

Key result

Duration:

48 h

Dose descriptor:

other: NOEL

Effect conc.:

>= 200 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

contact

Contact Tests

The 20 µg bee^-1dose level of the formulation required the application of two 1 µL drops. Therefore this treatment was not strictly comparable with the others which received 1 µL. Consequently, it was excluded from the statistical analysis. This had no effect on the conclusions reached as to the LD50 value or the NOEL because of the total lack of observed effects on bees in this treatment.

There was no mortality attributable to technical captan so that the 24- hour LD50s were greater than the highest dose tested: 200 and 20 µg bee^-1, respectively. The 48- hour results were similar.

There were no treatment related sublethal effects observed in bees treated with technical captan. Using the combined mortality and sub-lethal effects values, the NOELs were therefore equal to or greater than the highest dose tested (200 and 20 µg bee^-1, respectively).

Oral Tests

There was no mortality or sublethal effects attributable to either technical Captan. Therefore, the 24- and 48- hour LD50 values were greater than and the NOELs equal to or greater than the highest doses tested: 100 µg bee^-1for technical captan.

Overall there were no treatment-related mortalities or sublethal effects of captan in the oral or contact

tests at any dose at any assessment time. Mortality following treatment with dimethoate occurred at expected levels.

Validity criteria fulfilled:

not specified

Conclusions:

The 24 and 48-hour oral LD50 of captan to the honey bee is higher than 100 µg captan/bee. The 24 and 48-hour contact LD50 of captan to the honey bee is higher than 200 µg captan/bee.

Executive summary:

Laboratory tests was carried out on captan technical. There were two tests for each route of administration for technical captan: a rangefinder test and a definitive test based on the results of the rangefinder test.

The 24 hour contact LD50 values for technical captan was >200 and >20 µg bee^-1, respectively. The 24-hour oral LD50 values for technical captan was >100 and >20 µg bee^-1. The No Observed Effect Levels (NOELs) were greater than, or equal to, the highest dose tested in each case. Results obtained for dimethoate tested concurrently as a toxic standard indicated that the bees were reacting normally under the test conditions

Description of key information

1) Toxicity to terrestrial arthropods (Apis mellifera): LD50 (oral, 24h and 48h) >100 µg captan/bee,

LD50 (contact, 24h and 48h) >200 µg captan/bee for worker Honey bees (Apis mellifera),

Guideline UK MAFF PSPS Working Document D3 (1979).

 

2) Toxicity to terrestrial arthropods (springtail Folsomia candida):

LC50 (median lethal concentration): > 1000 mg a.i./kg soil dry weight.

With respect to progeny, the 28-day EC50 (median effect concentration): 807.9 mg a.i./kg soil (95% confidence limits = 648.3 and 1103.6 mg a.i./kg soil).

Based on statistical comparisons, the NOEC for effects on reproduction: 177.9 mg a.i./kg soil dry weight.

LOEC: 316.3 mg a.i./kg soil dry weight.

Key value for chemical safety assessment

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

177.9 mg/kg soil dw

Additional information

The result show that the 24-hour contact LD50 values for technical captan was >200 and >20 µg bee^-1, respectively. These results indicate that the technical material is 'virtually non-toxic' to bees in the laboratory under the conditions of these tests (using the classification of the International Commission for Bee Botany-Second Symposium on harmonisation of methods for testing the toxicity of pesticides to bees, Hohenheim, West Germany, 21-23 September 1982). There were no treatment effects at the doses tested there is no evidence of any difference in the level of safety. There were no treatment related sublethal effects for the technical material so that the NOEL were ≥200 and ≥20 µg ai bee^-1,respectively. There were no significant changes in the results in either the contact or the oral tests after 48 hours compared with 24 hours indicating that there were no delayed effects.