1-[(4-chlorophenyl)methyl]-1-cyclopentyl-3-phenylurea

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:

supporting study

Study period:

2006-08-21 to 2006-10-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)

Version / remarks:

1999

Deviations:

no

GLP compliance:

yes

Application method:

mixed into soil

Specific details on test material used for the study:

The test material is in a reddish form.

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: 100 mg of Pencycuron DS 12.5 were weighed using an analytical balance and fine quartz sand was added until a final weight of 50 g was reached. After mixing with a spoon to reach a homogeneous distribution of the test item within the sand the mixture was added to artificial soil with reduced sand fraction equivalent to 150 g dry weight resulting in a concentration of 500 mg test item/kg soil dry weight. There was no deviation to the target concentration. The prepared soil was mixed with a laboratory mixer for at least 1 minute to ensure a homogeneous distribution. Each group was treated in one batch and then split into 5 replicates.
- Controls: the control was untreated and moistened with deionised water.

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

- Common name: Springtails (Folsomia candida)
- Age at test initiation: 10-12 days old
- Stage at test initiation: adults

Study type:

laboratory study

Limit test:

yes

Total exposure duration:

28 d

Test temperature:

20°C - 21°C

pH (if soil or dung study):

Test start: 5.5 - 5.9; test termination: 5.5 - 5.6

Humidity:

Test start: 31% to 32% equivalent to 55% to 56% of the maximum water holding capacity; test termination: 30% to 31% equivalent to 52% to 54% of the maximum water holding capacity.

Photoperiod and lighting:

Light Intensity: 540 - 610 lux
Photoperiod: 16 h light: 8 h dark

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Glass containers (volume: 100 ml; diameter: 5cm), closed tightly to avoid water evaporation.
- Amount of soil or dung or substrate: 30 g ± 1.5 g artificial soil fresh weight.
- No. of organisms per container (treatment): 10 per container
- No. of replicates per treatment group: 5 replicates
- No. of replicates per control: 5 replicates

SOURCE AND PROPERTIES OF SOIL
- Composition (if artificial substrate): According to OECD 207: 10% Sphagnum-peat, air-dried and finely ground (2 mm); (Floragard, Vertriebs GmbH fur Gartenbau, 26138 Oldenburg, Germany), 20% Kaolin clay (Kaolinite content >30%) (Erbsloh, 65558 Lohrheim, Germany), approximately 0.5% chalk (CaCOs) added to adjust pH to 6.0 ± 0.5 (Merck, 64293 Darmstadt, Germany), and approximately 69.5% fine quartz-sand (F34) containing more than 50% by mass of particle size 0.05 mm to 0.2 mm; (Quarzwerke Frechen, Postfach 1780, 50207 Frechen, Germany).
- Maximum water holding capacity (in % dry weight): 57% of the dry weight

OTHER TEST CONDITIONS
- Photoperiod: 16 h light: 8 h dark
- Light intensity: 540 - 610 lux

Nominal and measured concentrations:

Nominal concentration of 500 mg a.s./kg soil dry weight.

Reference substance (positive control):

yes

Remarks:

Betosip

Toxic reference:

Betosip

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 61.5 other: mg a.s./kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: mortality and reproduction

Remarks on result:

other: The endpoint for a.s. was given in the DAR 2009.

Details on results:

Mortality
The mortality data are shown in Table 3. Mortality of adult Folsomia candida at the concentration of 500 mg a.s/kg soil dry weight was 18%, which was not significantly different compared to the control where 16% of the Collembola died (Fisher Exact test, a = 0.05, two-sided). Therefore, the No Observed Effect Concentration (NOEC) for mortality was determined to be 500 mg a.s./kg soil dry weight. The LC50 was estimated to be greater than 500 mg a.s./kg soil dry weight.

Behaviour
No abnormal behaviour or conditions were observed with the surviving Collembola.

Reproduction
There were no statistically significant effects on reproduction of Folsomia candida at the concentration of 500 mg a.s./kg soil dry weight (Student-t test, a = 0.05, one sided smaller). Therefore, the No Observed Effect Concentration (NOEC) was determined to be 500 mg a.s./kg soil dry weight The reproduction data are shown in Table 4. The EC50 was estimated to be greater than 500 mg a.s./kg soil dry weight.

Results with reference substance (positive control):

The most recent toxic reference test with phenmedipham did show statistically significant effects on reproduction at concentrations of >37.6 mg Betosip/kg soil dry weight; the EC50 for reproduction was calculated to be 102.3 mg Betosip/kg soil dry weight. Mortality was statistically significantly higher compared to the control at concentrations >202 mg Betosip/kg soil dry weight.

See "Attachments" in "Overall remarks, attachments" for the tables.

Validity criteria fulfilled:

yes

Remarks:

The mean mortality was 16% (<20%), number of juvenile Collembola per replicate was 522 to 700 (>100 instars per container), and the coefficient of variation (v) of the control reproduction was 11.3% (<30%).

Conclusions:

Pencycuron DS 12.5 did not cause significant effects on mortality or reproduction of Folsomia candida at the concentration of 500 mg a.s./kg soil dry weight. The overall No Observed Effect Concentration (NOEC) was determined to be 500 mg a.s./kg soil dry weight.

Executive summary:

This study was conducted in order to determine the effects of Pencycuron DS 12.5 on mortality and reproduction of the Collembola Folsomia candida in artificial soil. Collembola are ubiquitous throughout many soil types and contribute to soil fertility through their detritus feeding activities. They are also an integral part of the soil food chain. Folsomia candida is an easily reared species of Collembola and amenable to good experimental design. The test was conducted at a nominal concentrations of 500 mg a.s./kg artificial soil (dry weight) alongside an untreated control (and moistened with deionized water). After 28 days, the number of surviving adult springtails as well as the number of offspring was determined. Pencycuron DS 12.5 did not cause significant effects on mortality or reproduction of Folsomia candida at the concentration of 500 mg a.s./kg soil dry weight. The overall No Observed Effect Concentration (NOEC) was determined to be 500 mg a.s./kg soil dry weight.

Reference 2

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2001-08-13 to 2002-04-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)

Version / remarks:

1999

Deviations:

no

GLP compliance:

yes

Application method:

mixed into soil

Specific details on test material used for the study:

The test material is in a yellowish form.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

- Method of mixing into soil or dung: A stock solution was prepared by weighing 1.0 g of Pencycuron - PB - Amine using an analytical balance and dissolving the test item in 25 ml of acetone. A dilution row was prepared by adding 10 ml of acetone to 10 ml of the stock solution or the previous dilution. 5 mL of the stock solution or the corresponding dilution were added to 50 g of fine quartz sand. After evaporation of the solvent under a fume hood the test item blended sand was mixed thoroughly into 150 g of artificial soil with a laboratory mixer for at least 1 minute to ensure a homogenate distribution. In the course of applying the test item, the soil was ventilated and moistened.
- Controls: the control was treated with deionised water, while the solvent control was treated with 5 mL of acetone and deionised water.

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

TEST ORGANISM
- Common name: Springtails (Folsomia candida)
- Age at test initiation: 10-12 days old
- Stage at test initiation: adults

Study type:

laboratory study

Limit test:

no

Total exposure duration:

28 d

Test temperature:

18 - 22°C

pH (if soil or dung study):

Test start: 5.8 - 6.2; test termination: 5.8 - 5.9

Humidity:

Test start: 33% to 34%, corresponding to 49% to 50% of the water holding capacity; test termination: 31% to 33%, corresponding to 46% to 49% of the water holding capacity.

Photoperiod and lighting:

Light Intensity: 440 - 752 lux
Photoperiod: 16 h light: 8 h dark

Details on test conditions:

TEST SYSTEM
- Test container (material, size): glass vessels (volume: 100 ml; diameter: 5 cm), closed tightly by plastic-lids to avoid water evaporation from the artificial soil.
- Amount of soil: 30 g ± 5% (wet weight) artificial soil.
- No. of organisms per container (treatment): 10 per container.
- No. of replicates per treatment group: 5 replicates per treatment group.
- No. of replicates per control: 5 replicates per control.

SOURCE AND PROPERTIES OF SOIL
- Composition (if artificial substrate): according to OECD 207: 10% Sphagnum-peat, air-dried and finely ground, 20% Kaolin clay, approximately 0.4% Calcium carbonate (CaCO3) extra pure to adjust pH to 6.0 ± 0.5 - approximately 69.6% fine quartz-sand (grain size of more than 50% of the particles between 0.05 - 0.2 mm).
- Maximum water holding capacity (in % dry weight): 68.03% of the dry weight.

OTHER TEST CONDITIONS
- Photoperiod: 16 h light: 8 h dark
- Light intensity: 440 - 752 lux

Nominal and measured concentrations:

Nominal concentrations of 62.5, 125, 250, 500 and 1000 mg/kg artificial soil (dry weight).

Reference substance (positive control):

yes

Remarks:

Betosip

Toxic reference:

Betosip

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

500 other: mg product/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 other: mg product/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

60 other: mg a.s./kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: The endpoint for a.s. was given in the DAR 2009.

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 120 other: mg a.s./kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Remarks on result:

other: The endpoint for a.s. was given in the DAR 2009.

Details on results:

Mortality
As the results of the control and the solvent control were comparable (Fishers Exact Test, a = 0.05, two-sided) the data of the control and the solvent control were pooled and the test item treatment groups as well as the toxic standard were compared against the pooled data. The mortality results are shown in Table 3. In this study statistically significant acute toxic effects of Pencycuron - PB - Amine to Folsomia candida were observed at the concentration of 1000 mg/kg artificial soil (dry weight) (Fisher exact test, a = 0.05).

Behaviour
No abnormal behaviour or conditions were observed with the surviving Collembola.

Reproduction
The reproduction results are shown in Table 4. The reproduction in the control reached 818 ± 146 juveniles (mean ± SD of 10 replicates of the control and solvent control, which were pooled since they showed no statistically difference, Student-t test, a = 0.05). In the groups treated with Pencycuron - PB – Amine a dose related decrease of juvenile Collembola was observed. The numbers of juveniles were not significantly different compared to the control up to the concentration of 250 mg/kg artificial soil (dry weight). At a concentration of 500 and 1000 mg/kg artificial soil (dry weight) the reproduction rates were significantly reduced compared to the pooled control (Dunnett test, a = 0.05, one sided smaller). Reproduction in the toxic standard treatment was significantly reduced to 51.1% of the control (Student t-Test, a = 0.05, one sided smaller).

Results with reference substance (positive control):

The data on mortality caused by the toxic standard as well as the effect on reproduction, can be found in Tables 3 and 4 respectively.

See "Attachments" in "Overall remarks, attachments" for the tables.

Validity criteria fulfilled:

yes

Remarks:

Mortality was 13% and thus did not exceed 20%. The mean of five replicates was 818 juvenile Collembola and thus exceeded 100 instars per control vessel. The coefficient of variation of reproduction in control was 18% and thus did not exceed 30%.

Conclusions:

A test item related statistically significant mortality occurred at 1000 mg Pencycuron - PB - Amine/kg artificial soil (dry weight), the LC50 (mortality) was determined as 672.3 mg/kg artificial soil (dry weight). NOEC (mortality) was determined to be 500 mg/kg substrate. Reproduction was significantly influenced at the test concentration of 250 mg/kg artificial soil (dry weight); the NOEC (reproduction) was 250 mg Pencycuron - PB - Amine/kg artificial soil (dry weight), the EC50 was calculated as 511.3 mg/kg artificial soil (dry weight).

Executive summary:

This study was conducted in order to determine the effects of Pencycuron - PB - Amine on reproduction of the Collembola, Folsomia candida in artificial soil. Collembola are ubiquitous throughout many soil types and contribute to soil fertility through their detritus feeding activities. They are also an integral part of the soil food chain. Folsomia candida is an easily reared species of Collembola and amenable to good experimental design. The test was conducted at the following nominal concentrations of the test substance which was mixed into an artificial soil: 62.5, 125, 250, 500 and 1000 mg/kg dry weight soil alongside a control (treated with deionised water) and solvent control (with acetone and deionised water). After 28 days, the number of surviving adult springtails as well as the number of offspring was determined. A test item related statistically significant mortality occurred at 1000 mg Pencycuron - PB - Amine/kg artificial soil (dry weight), the LC₅₀ (mortality) was determined as 672.3 mg/kg artificial soil (dry weight). NOEC (mortality) was determined to be 500 mg/kg substrate. Reproduction was significantly influenced at the test concentration of 250 mg/kg artificial soil (dry weight); the NOEC (reproduction) was 250 mg Pencycuron - PB - Amine/kg artificial soil (dry weight), the EC₅₀ was calculated as 511.3 mg/kg artificial soil (dry weight).

Description of key information

Two long-term soil arthropods studies were conducted to determine the effect of Pencycuron on reproduction of Folsomia candida in a laboratory test. Reproduction was determined after 28 days, resulting in the NOEC of ≥120 and ≥61.5 mg a.s./kg soil dw, respectively.

An acute study with honey bees is availabe and executive summaries below.

Kling, 2001

The acute oral toxicity and acute contact toxicity of Pencycuron was assessed in a limit test in Apis mellifera. Under laboratory conditions Apis mellifera 50 worker bees per treatment were exposed for 48 hours to a single dose of 100.0 µg a.s. per bee for topical application (contact limit test) and to a single dose of 98.5 µg a.s. per bee for feeding (oral limit test, value based on the actual intake of the test item).

The results can be considered as valid, as all validity criteria of the test were met: control mortality is <10% in the oral and in the contact test, LD₅₀ (24 h) of the toxic standard in the oral test equals 0.12 mg a.s./bee, the LD₅₀ (24 h) of the toxic standard in the contact test equals 0.16 mg/bee. LD₅₀ oral and contact were determined to be >98.5 µg a.s./bee and >100.0 µg a.s./bee.

Test species	Result	Assessment	Reference
Apis mellifera	Contact 48-h LD50 > 100.0 µg a.s./bee Oral 48-h LD50 > 98.5 µg a.s./bee	Summary	Kling (2001)
Folsomia candida	28-d NOEC = 60.0 mg a.s./kg soil dw based on mortality	Supporting study	Meister (2002)
Folsomia candida	28-d NOEC = 61.5 mg a.s./kg soil dw based on mortality and reproduction	Supporting study	Lührs (2006)

Key value for chemical safety assessment

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

60 mg/kg soil dw