Registration Dossier

Ecotoxicological information

Toxicity to soil microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
toxicity to soil microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-02-24 to 2011-09-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
no
Details on sampling:
- Sampling procedure for determination of formed nitrate in the test assays: three samples from of each test assay were taken at the start of exposure, after 7 days and after 28 days for the determination of the nitrate content. Therefore the amount of about 23.5 g was weighed into glass bottles and 100 mL demineralized water were added to aliquots of the test assays. The soil suspensions were shaken for about 1 hour at 150 rpm with a laboratory shaker. Volumes of about 10 mL of the suspensions were taken and centrifuged for about 30 minutes at 4500 rpm. The content of formed nitrate was measured as nitrate nitrogen in each supernatant using an analytical kit no. LCK 339 from. Hach-Lange. The nitrate values of the test assays with test substance were compared with the values of formed nitrate of the blank control.
Vehicle:
no
Details on preparation and application of test substrate:
AMENDMENT OF SOIL
- Type of organic substrate: Natural soil, type 2.3

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: The required amount of the test substance for each test concentration were balanced with 5 g quartz sand as carrier (equal to 10 g/kg dry weight) and mixed well. The control assay was prepared with the same amount of quartz sand without test substance.
Test organisms (inoculum):
soil
Total exposure duration:
28 d
Test temperature:
20.3 – 21.0°C, mean value 20.6°C
Moisture:
- Water content of the soil (measured):4.5 g/100g dry weight
- Water content of the test mixture (soil, test substance and quartz sand): 16 g/100 g dw
- Water content of the soil during exposure: 45 ± 5% of the WHCmax
Details on test conditions:
TEST SYSTEM
- Testing facility: BASF SE, Ludwigshafen, Germany
- Amount of soil: ca. 581 g
- No. of replicates per concentration: 2
- No. of replicates per control: 2

SOIL INCUBATION
- Method: Series of individual subsamples

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Source of substrate: Landwirtschaftliche Untersuchungs- und Forschungsanstalt Speyer, Obere Langgasse 40, 67346 Speyer, Germany
- Geographical reference of sampling site: Im Bildgarten, Nr 508/2
- Depth of sampling: Approx. 20 cm
- Soil taxonomic classification: Silty sand according to German DIN
- pH: 6.7 ± 0.3
- Treatment with pesticides or fertilizers: The soil was not treated with crop protection products for > 4 years. The sampling field was not cultivated for 5 years and no fertilizer application was performed during the last 5 years before sampling the soil.
- Initial nitrate concentration for nitrogen transformation test (mg nitrate/kg dry weight): 99 to 119
- Cation exchange capacity: 10.0 ± 2.0 mval/100 g
- Pretreatment of soil: Drying for 6 days at room temperature, Presieving with 10 mm screen, Last sieving 2 mm screen, water content 4.5 g/100 g dw, at the day of exposure the soil was mixed with 16.6 g luzerne meal.
- Initial microbial biomass: 107.8 ± 0.1 mg carbon/kg dw/h

EFFECT PARAMETERS MEASURED:
Nitrogen transformation after 7 and after 28 days.
Nominal and measured concentrations:
Nominal concentrations: 62.5, 125, 250, 500 and 1000 mg/kg dw
Reference substance (positive control):
no
Duration:
7 d
Dose descriptor:
EC10
Effect conc.:
970 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Duration:
7 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:
7 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:
EC10
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:
EC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
nitrate formation rate
Endpoint:
toxicity to soil microorganisms
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See 'Attached justification'
Reason / purpose:
read-across source
Key result
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
1 000 mg/kg soil dw
Remarks on result:
other: as determined from read-across to C13 alcohol, branched

Description of key information

No toxic effects have been observed in studies with terrestric microorganisms.

Key value for chemical safety assessment

Additional information

For Isotridecanol, one of the components of the C13 -15 -branched an linear alcohol, data is available from a study according to OECD 216 and in compliance with GLP criteria (BASF SE, 2011). In this study soil nitrifying microorganisms were exposed to nominal test concentrations for 0 (control), 62.5, 125, 250, 500 and 1000 mg/kg dw for a period of 28 days. The required amounts of test substance were weighed and mixed with an appropriate amounts of quartz sand and this mixture added to soil. The soil moisture content was ca. 45% of the maximum water holding capacity. Nitrogen transformation was measured after 7 and after 28 days exposure. From this study a 28-d EC10 of 1000 mg/kg soil dw was determined.