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

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Remarks:

Determination of effects on reproduction

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-06-21 to 2001-09-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 11268-2 (Effects of Pollutants on Earthworms. 2. Determination of Effects on Reproduction)

Version / remarks:

First edition 1998-07-01

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: BBA, Guidelines for the Testing of Plant Protection Products Within Registration, Part VI, 2 - 2

Version / remarks:

January 1994

Deviations:

yes

Remarks:

since treated potatoes had been tested in this study, larger test containers with the 30-fold amount of artificial soil had been used and the peat content in the soil was 5%.

GLP compliance:

yes

Specific details on test material used for the study:

The test material is in a red powder form.

Analytical monitoring:

no

Details on preparation and application of test substrate:

The test soil consists of 74% fine quartz sand (83% of the sand has a particle size of 0.05 - 0.2 mm), 5% dried, finely ground peat (sphagnum peat; pH 2 - 4), 20% kaolin (kaolinite content of about 36%, pH value ca 7, "Kaolin W", from Erbsloh / Geisenheim) and around 1% calcium carbonate (pure) to adjust the pH value to 6 ± 0.5 .

The artificial soil was first of all mixed dry from these components and the food in a plough-share mixer, and moistened with the volume of water required for the final artificial soil. Test containers were plastic containers of 56 cm length, 36 cm width and 22 cm height (inner size). The resulting artificial soil surface area was 0.2 m2. Each test container was filled with 15 kg dry weight soil (= 18.673 kg wet weight). The potatoes were placed in a depth of 5 cm below the surface. Two replicates were used per dosage. Each container was covered with a transparent plastic sheet to prevent evaporation and to allow lighting. They were labeled (study number, rate, series number). The artificial soil was acclimatized for 1 day under test conditions before earthworms were placed on the test soil. All test containers were transferred into a climatic chamber after application.

The moisture content of the peat and the test soil as well as the maximum water capacity of the test soil were determined by drying the soil at high temperatures up to constant weight. The pH was determined with an electrode (WTW pH- Meter 330) The dressing of the potatoes was conducted with an application rate of 25 mg a.s./100 kg potatoes. For the study potatoes with a weight of aproximatly 40 g (corresponding to 2000 kg potatoes/ha) were chosen and treated with 82.6 mg formulation. The potatoes had been randomly selected for the test containers.

One day prior to the start of the study, earthworms were removed from the breeding substrate and kept in the test soil (without test substance) under the test conditions for acclimatization. They were removed from this artificial soil and transferred to test boxes two hours before the dressed potatoes were added. Thirty earthworms were placed in each test container. Earthworms were individually weighed at the start of the study. They were put into the test containers in a randomized procedure. At the start of the study, they had a mean weight of 0.30 g.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworm (Eisenia fetida)
- Age at test initiation: To obtain earthworms for the study, adult earthworms of breeding boxes were transferred to freshly prepared culture substrate for reproduction. The earthworms were removed after 4 weeks. After further 10 months, adult earthworms which developed from cocoons, were selected for the study.
- Weight at test initiation: At the start of the study, they had a mean weight of 0.30 g.

ACCLIMATION
One day prior to the start of the study, earthworms were removed from the breeding substrate and kept in the test soil (without test substance) under the test conditions for acclimatization.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

28 d

Remarks:

After 28 days the number of surviving animals and their weight alteration was determined. They were then removed from the artificial soil. After further 28 days, the number of offsprings was determined.

Test temperature:

20 ± 2°C

pH:

6 ± 0.5 (Test start: 6.24 - 6.26; test termination: 6.25 - 6.33)

Moisture:

Test start: 19.38 - 19.88%; test termination: 20.9 - 23.8%

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Test containers were plastic containers of 56 cm length, 36 cm width and 22 cm height (inner size).
- Amount of soil or substrate: Each test container was filled with 15 kg dry weight soil (= 18.673 kg wet weight).
- No. of organisms per container (treatment): 30 earthworms per container.
- No. of replicates per treatment group: 2 replicates
- No. of replicates per control: 2 replicates

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): The test soil consists of 74% fine quartz sand (83% of the sand has a particle size of 0.05 - 0.2 mm), 5% dried, finely ground peat (sphagnum peat; pH 2 - 4), 20% kaolin (kaolinite content of about 36%, pH value ca 7, "Kaolin W", from Erbsloh / Geisenheim) and around 1% calcium carbonate (pure) to adjust the pH value to 6 ± 0.5.
- Maximum water holding capacity (in % dry weigth): 55.03 – 58.32%

OTHER TEST CONDITIONS
- Photoperiod: 16:8 hours light-dark cycle.
- Light intensity: 400 - 800 lux

Nominal and measured concentrations:

Nominal concentrations of 2000, 4000 and 10000 kg potatoes/ha.

Reference substance (positive control):

yes

Remarks:

Derosal (active ingredient: 36 % Carbendazim)

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 10 000 other: kg dressed potato/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

>= 10 000 other: kg dressed potato/ha

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

>= 3.3 other: mg a.s./kg soil ww

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:

The results of the pH determinations of the artificial soil and its moisture content are summarized in Table 1. Tables 2 and 3 summarize the amount of food added and portion ingested by earthworms during the study.

The mortalities (%) and weight changes (%) of the adult worms after 28 days are summarized in Table 4. The individual values of the study are given in Table 5. Table 6 lists the weight of individual earthworms at the start of the study. Abnormalities, e.g. changes in behavior, were not observed. The number of juvenile earthworms at the end of the study after 56 days are summarized in Table 7. In this table, the total numbers of juvenile earthworms per test container are shown which had been calculated according to the individual results of the evaluated soil samples given in table 8 (6 samples per test container, corresponding to 6 x 0.5 kg dry weight soil, which is 20% of the total soil of a test container).

The mortality rate in the control was below 10% which can be regarded as the limit for natural mortality according to test guidelines. Reproduction was greater than 3 juveniles per adult indicating acceptable reproductive output. Soil moisture and pH were maintained in acceptable ranges through the test. These data along with results from the positive control study indicate that this is a valid test.

Significant mortality or a significant body weight reduction of adult earthworms was not observed at any rate. Also, the number of offspring was not significantly reduced at any rate.

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

Results with reference substance (positive control):

Under the same conditions, a study was carried out with the reference substance Derosal (active ingredient: 36% Carbendazim. The following dosages had been tested by application on the soil surface at the start of the study: 0.10, 0.25 and 0.50 kg/ha. Mortality of adult earthworms as compared to control organisms was not observed at any dosage. The body weight reduction was significant at 0.25 and 0.5 kg/ha. Only the highest dosage of 0.5 kg/ha reduced the numbers of juvenile earthworms by 46%. The no-observed-effect-level (NOEL) was 0.10 kg/ha (= 0.036 kg a.s./ha) and the lowest-observed-effect-level (LOEL), 0.25 kg/ha (= 0.090 kg a. s./ha).

Validity criteria fulfilled:

yes

Conclusions:

Mortality or a significant body weight reduction of adult earthworms was not observed in earthworms exposed in an artificial soil to treated potatoes up to 10000 kg potatoes/ha. Also, the number of offspring was not reduced at any rate.

Executive summary:

This study was conducted in order to determine the influence of Pencycuron DS 12.5 on the reproduction of adult earthworms (Eisenia fetida) in an artificial soil with 5% peat content. The test was conducted at the following nominal concentrations of the test substance: 0 (control), 2000, 4000 and 10000 kg potatoes/ha. After 28 days the number of surviving animals and their weight alteration was determined. They were then removed from the artificial soil. After further 28 days, the number of offsprings was determined. No mortality was observed in the control or any of the treatments. Also, significant body weight reduction of adult earthworms was not observed at any rate. Furthermore, the number of offspring was not reduced at any rate. The NOEC was 10000 kg dressed potatoes/ha; the potatoes were dressed with 25 g a. s./100 kg potatoes.

Description of key information

A chronic earthworm study was conducted to determine the effect of Pencycuron on reproduction of the earthworm Eisenia fetida in a laboratory test. Reproduction was determined after 56 day, resulting in the NOEC of 3.3 mg/kg soil dw.

 

Test species	Result	Assessment	Reference
Eisenia fetida	14-d LC50 >10000 mg a.s./kg soil dw based on mortality	Supporting study	Heimbach (1999)
Eisenia fetida	56-d NOEC ≥3.3 mg a.s./kg soil dw based on reproduction	Key study	Meisner (2001)
Eisenia fetida	56-d NOEC = 100 mg a.s./kg soil dw based on reproduction	Supporting study	Heimbach (1999)

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

10 000 mg/kg soil dw

Long-term EC10, LC10 or NOEC for soil macroorganisms:

3.3 mg/kg soil dw