(E)-anethole

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

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:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Version / remarks:

2000

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

The test item was pipetted onto quartz sand (1 % of the total soil amount per treatment) for each test concentration separately, mixed thoroughly and applied to the surface of the soil. Additional
demineralized water was added to adjust the humidity of the soil. Afterwards, the soil was mixed with a mixer to ensure a homogeneous distribution of the test item in the soil and portioned into the replicates.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

19.7 -21.8 °C

Moisture:

Test start: 40.2 - 40.8 % MWHC
Test end: 40.0 - 41.3 % MWHC

Details on test conditions:

TEST SYSTEM
- Test container: Plastic boxes (volume 1.0 L, food grade) with perforated tops to enable gas exchange.
- Amount of soil: 400 g soil DW
- No. of replicates per concentration: 3
- No. of replicates per control: 3

SOIL INCUBATION
- Method: Incubation was performed in bulk and subsamples were taken

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site: R-439683; H-5449554
- Soil history: Cultures: 2017 - 2021: uncultivated; Fertilisation: 2017 - 2021: none
- Treatments with pesticides or fertilizers: No crop protection products applied during the year of sampling and 4 preceding years
- Depth of sampling: 0- 20 cm
- Soil texture
- % sand: 57.6
- % silt: 35.1
- % clay: 7.4
- Soil taxonomic classification: silty sand
- Soil classification system: German DIN classification
- pH (in water): 6.2
- Initial nitrate concentration for nitrogen transformation test (mg nitrate/kg dry weight): 13.2
- Maximum water holding capacity (in % dry weigth): 35.7
- Cation exchange capacity (meq/ 100 g): 6.0 +- 0.9
- Pretreatment of soil: The soil was manually cleared of large objects and then sieved to a particle size of up to 2 mm. The soil was adjusted to about 42 % of its maximum water holding capacity with demineralized water. The soil amounts were amended with powdered lucerne-greengrass-meal (0.5 % of soil dry weight)
- Storage (condition, duration): The soil was stored for 63 / 66 days in the dark at 4 - 6 °C in a climatic room
- Initial microbial biomass as % of total organic C: 4.54

DETAILS OF PREINCUBATION OF SOIL: The soil was pre-incubated at room temperature (ca. 20 °C) for 21 / 24 days to adapt the micro-organisms to test conditions before the start of the study.

EFFECT PARAMETERS MEASURED: Measurements of inorganic nitrate were carried out after 0, 7, 14 and 28 days

RANGE-FINDING STUDY
- Test concentrations: 10, 100, 1000 mg/kg soil DW
- Results used to determine the conditions for the definitive study: Only inhibitory effects in the 1000 mg/kg DW test concentration

Nominal and measured concentrations:

1000, 500, 250, 125, 62.5 mg/kg soil DW

Reference substance (positive control):

yes

Remarks:

Cyanoguanidine is tested yearly at a concentration of 50 mg/kg soil dry weight

Key result

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

Key result

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

710 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

250 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels:
- Inhibition of Inorganic-N Contents: 56% (compared to untreated control) after 28 d
- Inhibition of Inorganic-N Formation Rates: 83% (compared to untreated control) after 28 d


- Other:

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (28 days) of the test item on the metabolic activity of soil-microorganisms was determined to be > 1000 mg/kg soil dry weight. The EC10 (28 days) was determined to be 710 mg/kg soil dry weight.

Executive summary:

The effects of the test item on the metabolic activity of soil micro-organisms were determined according to OECD Guideline 216 (2000) over 28 days. The test item was applied via quartz sand with the test concentrations 1000 - 500 - 250 - 125 - 62.5 mg product/kg soil dry weight (factor 2). Untreated soil was tested as control under the same test conditions as the test item concentrations. Standard soil, moistened to nominally 45 % of its maximal water holding capacity, was used. Plastic boxes (volume 1.0 L) with perforated tops to enable gas exchange and filled with 400 g soil dry weight were used. The effects of the test item on the metabolic activity of the nitrogen-N formation rate (nitrate) were measured on the day of treatment (day 0) and after 7, 14 and 28 days. On day 28 the EC50 for nitrogen transformation in soil measured as nitrate was > 1000 mg/kg soil dry weight, the EC10 for nitrogen transformation in soil measured as nitrate was 710 mg/kg soil dry weight.

Description of key information

Based on results of an OECD 216 compliant study with the test item an EC10 (based on the Nitrate-N formation rate) of 710 mg/kg soil dw was determined as key value for the risk assessment.

Key value for chemical safety assessment

Short-term EC50 for soil microorganisms:

1 000 mg/kg soil dw

Long-term EC10 or NOEC for soil microorganisms:

710 mg/kg soil dw

Additional information

The effects of the test item on the metabolic activity of soil micro-organisms were determined according to OECD Guideline 216 (2000) over 28 days. The test item was applied via quartz sand with the test concentrations 1000 - 500 - 250 - 125 - 62.5 mg product/kg soil dry weight (factor 2). Untreated soil was tested as control under the same test conditions as the test item concentrations. Standard soil, moistened to nominally 45 % of its maximal water holding capacity, was used. Plastic boxes (volume 1.0 L) with perforated tops to enable gas exchange and filled with 400 g soil dry weight were used. The effects of the test item on the metabolic activity of the nitrogen-N formation rate (nitrate) were measured on the day of treatment (day 0) and after 7, 14 and 28 days. On day 28 the EC50 for nitrogen transformation in soil measured as nitrate was > 1000 mg/kg soil dry weight, the EC10 for nitrogen transformation in soil measured as nitrate was 710 mg/kg soil dry weight.