N,N''-(isobutylidene)diurea

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

No data relating to untreated controls were provided. Study was assessed with a reliability of two in OECD SIDS urea and in contrast, with a reliability of four in OECD SIDS of this substance. The observed effects were attributed to the lowering of pH observed in parallel with IBDU application in the absence of liming. Since this study provides evidence on the harmfullness of IBDU in long term treatments among 20 years, we believe it can be considered for covering the endpoint of long term toxicity to soil macroorganisms.

Principles of method if other than guideline:

other: field test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Lumbricus sp.

Animal group:

annelids

Study type:

field study

Substrate type:

natural soil

Remarks:

20 years

Key result

Duration:

365 d

Dose descriptor:

other: EC

Effect conc.:

216 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass and number of earthworms

Effects of fertilizers on lumbricid earthworms in uncultivated turfgrass on loamy sand soil were related to their effects on soil acidity. IBDU had effects on earthworm numbers and biomass and lowered pH dose-dependently by 1 to 1.5 units. Endogaeic species of earthworms such as Aporrectodea spp. were more strongly affected than the epigaeic group of Lumbricus spp., although an exception was noted for A. caliginosa tuberculata. Strongly acidified soils contained more organic matter than soils which were less acidified, accumulations of soil organic matter were associated with accumulations of surface thatch. The study indicates that the application of fertilizers to grasslands for long periods may have a deleterious effect on earthworms in the absence of liming, as the effects were related to changes in soil acidity.

In summary, this study revealed that, IBDU (2 applications per year of 180 kg N/ha = 216 mg IBDU/kg soil) had effects on earthworm numbers and biomass.

Reference 2

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Version / remarks:

1984

GLP compliance:

yes

Analytical monitoring:

no

Details on preparation and application of test substrate:

- Method of mixing into soil (if used): The test substance was pulverized in a mortar before weight in.
The test substance was weight in and added direct to each parallel (10 g quartz sand). Afterwards these
10 g quartz sand were mixed with 740 g of the substrate and 250 ml dernineralized water was added to
adjust the water content at 33 ± 2% of dry weight.
- Controls: yes

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: earthworm
- Source: supplier (Mrs . Haber from 64367 Mahltal-
Frankenhausen)
- Age at test initiation (mean and range, SD): adult, 9 months
- Weight at test initiation (mean and range, SD): 300-600 mg


ACCLIMATION
- Acclimation conditions (same as test or not): Before being used in the test, the animals were kept in boxes and fed with horse
manure.
- Adaptation: 24 h before the test, in test substrate without test substance

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

19.1°C-22.1°C

pH:

5.8 (at day 0)

Moisture:

33.1-33.3%

Details on test conditions:

see below: Any other information on materials and methods incl. tables

Nominal and measured concentrations:

Nominal concentrations: 125, 250, 500, 1000 mg/kg and control

Reference substance (positive control):

yes

Remarks:

chloracetamide

Duration:

14 d

Dose descriptor:

LC0

Effect conc.:

250 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

14 d

Dose descriptor:

LC100

Effect conc.:

1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

648 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

250 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

see below

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: LC50 (14d) = 16.7 mg/kg

LC50 (14 d): 648 (95% confidence limits 587-716) mg/kg

LC50 (7 d): 648 (95% confidence limits 591-712) mg/kg. 

No particular behavioural or morphological changes were observed.

Validity criteria fulfilled:

yes

Description of key information

Acute toxicity to earthworm: LC50 (14d): 648 mg/kg soil d.w.

Additional information

Acute toxicity to Eisenia fetida was tested in a study according to OECD guideline 207. The 14d- LC50 value was 648 mg/kg soil (BASF AG 2001). Ma et al. (1990) studied long-term effects (20 y) on nitrogenous fertilizers usage on lumbricid earthworms in soil. This study revealed that, IBDU (2 applications per year of 180 kg N/ha = 216 mg IBDU/kg soil) had effects on earthworm numbers and biomass. However, the effects were attributed to the lowering of pH observed in parallel with IBDU application in the absence of liming.