Registration Dossier

Ecotoxicological information

Toxicity to soil microorganisms

Currently viewing:

Administrative data

Endpoint:
toxicity to soil microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant OECD and EC guideline study, performed in recognized contract research organization, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.21 (Soil Microorganisms: Nitrogen Transformation Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
425-220-8
EC Name:
-
Cas Number:
5945-33-5
Molecular formula:
C39H34O8P2
IUPAC Name:
(1-methylethylidene)di-4,1-phenylenetetraphenyl diphosphate

Sampling and analysis

Analytical monitoring:
not required

Test substrate

Vehicle:
yes
Details on preparation and application of test substrate:
AMENDMENT OF SOIL
- Type of organic substrate: powdered lucerne-green-grass meal

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: vehicle stock solution added to dry quartz sand, evaporation of vehicle, incorporation into soil bulk

VEHICLE:
- Chemical name of vehicle: acetone
- Evaporation of vehicle before use: yes

Test organisms

Test organisms (inoculum):
soil

Study design

Total exposure duration:
28 d

Test conditions

Test temperature:
21 ± 1 °C
Moisture:
40% of the water holding capacity (± 5%)
Details on test conditions:
TEST SYSTEM
- Testing facility: dark, temperature controlled room
- Test container (type, material, size): glass jars
- Amount of soil: 50 g dry weight per test container
- No. of replicates per concentration: 18 (6 per sampling date)
- No. of replicates per control: 9 (3 per sampling date)
- No. of replicates per vehicle control: 9 (3 per sampling date)

SOIL INCUBATION
- Method: series of individual subsamples

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Specification: soil type 2.3 (field fresh), LUFA Speyer, Germany
- Geographical reference of sampling site: Germany / Rheinland-Pfalz / Offenburg; ''Im Bildgarten'', No. 507
- History of site
- Vegetation cover: uncultivated in sampling year and 4 former years
- Treatments with pesticides or fertilizers: no pesticides and no organic fertilization in sampling year and 4 former years
- Depth of sampling: ca. 20 cm
- Soil texture
- % sand: 62 ± 4.2
- % silt: 29 ± 3.6
- % clay: 9 ±1.4
- Soil taxonomic classification: sandy loam
- Soil classification system: USDA
- pH (in water): 7.0
- Initial nitrate concentration for nitrogen transformation test (mg nitrate/kg dry weight): about 90 mg/kg (after addition of powdered lucerne-green-grass meal)
- Maximum water holding capacity (in % dry weigth): 35.1 ± 2.0
- Cation exchange capacity (meq/100 g): 9.0 ± 3.0
- Storage (condition, duration): approx. 4 °C for approx. 2.5 months
- Initial microbial biomass as % of total organic C: 1.2

DETAILS OF PREINCUBATION OF SOIL (if any): prior to use, the soil was acclimated at approx. 21 °C for two days, shielded from light

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): nitrate formation rate after 7 and 28 days of exposure

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: 10, 100 and 1000 mg/kg dry soil equivalent
- Results used to determine the conditions for the definitive study: no significant effect on nitrogen transformation activity at all concentrations tested
Nominal and measured concentrations:
nominal: 1000 mg/kg soil (dry weight)
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Duration:
28 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Duration:
28 d
Dose descriptor:
EC25
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Reported statistics and error estimates:
Statistical analysis on the nitrate concentration values was performed using a Students t-test. All statistical analyses were performed using the SAS computer software package (SAS 1999 - 2001).

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable