Registration Dossier

Environmental fate & pathways

Biodegradation in soil

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in soil, other
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: persistence of methyl eugenol in soil.
- Short description of test conditions: soil consisted of 100 g of Lufkin fine sandy loam (BULL et al. 1970). Test was performed at 22ºC and 32ºC.
- Parameters analysed / observed: half-life in soil.
GLP compliance:
no
Test type:
laboratory
Specific details on test material used for the study:
RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: > 99% as determined by thin later chromatography (TLC)
- Specific activity: 9.5 mCi/mmole.


Radiolabelling:
yes
Oxygen conditions:
aerobic
Soil classification:
USDA (US Department of Agriculture)
Soil no.:
#1
Soil type:
sandy loam
% Clay:
20
% Silt:
22
% Sand:
58
% Org. C:
1.4
pH:
6.8
Details on soil characteristics:
SOIL COLLECTION AND STORAGE
- Geographic location: College Station, Texas
Soil No.:
#1
Duration:
0 h
Soil No.:
#1
Duration:
24 h
Soil No.:
#1
Duration:
48 h
Soil No.:
#1
Duration:
72 h
Soil No.:
#1
Duration:
96 h
Soil No.:
#1
Initial conc.:
100 mg/kg soil d.w.
Based on:
test mat.
Parameter followed for biodegradation estimation:
test mat. analysis
Soil No.:
#1
Temp.:
22ºC
Humidity:
100 g of soil was mixed with 15 mL H20 in a beaker.
Soil No.:
#1
Temp.:
32ºC
Humidity:
100 g of soil was mixed with 15 mL H20 in a beaker.
Details on experimental conditions:
1. PRELIMINARY EXPERIMENTS: No data

2. EXPERIMENTAL DESIGN
- Soil (g/replicate): 100 g
- No. of replication treatments: 3
- Test apparatus (Type/material/volume): environmental chamber

Test material application
- Volume of test solution used/treatment: 2 mL of a hexane solution containing 10 mg of methyl eugenol.
- Application method (e.g. applied on surface, homogeneous mixing etc.): Applied on surface
- Is the co-solvent evaporated: No

Any indication of the test material adsorbing to the walls of the test apparatus: No

Experimental conditions (in addition to defined fields)
- Moisture maintenance method: No data
- Continuous darkness: No, 14 h light/10 h dark.

Other details, if any:

3. OXYGEN CONDITIONS (delete elements as appropriate)
- Methods used to create the an/aerobic conditions: No specified
- Evidence that an/aerobic conditions were maintained during the experiment (e.g. redox potential): No specified

4. SUPPLEMENTARY EXPERIMENTS: No

5. SAMPLING DETAILS
- Sampling intervals: 0, 24, 48, 72 and 96 h
- Sampling method for soil samples: soils were extracted 5 times with ca. 20-mL portions of dichloromethane.





Key result
Soil No.:
#1
% Degr.:
98
Parameter:
test mat. analysis
Sampling time:
96 h
Remarks on result:
other: 32ºC
Key result
Soil No.:
#1
% Degr.:
81
Parameter:
test mat. analysis
Sampling time:
96 h
Remarks on result:
other: 22ºC
Key result
Soil No.:
#1
DT50:
ca. 6 h
Type:
not specified
Temp.:
32 °C
Key result
Soil No.:
#1
DT50:
16 h
Type:
not specified
Temp.:
22 °C
Transformation products:
not specified
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified
Details on results:
TEST CONDITIONS
- Anomalies or problems encountered (if yes): TLC analyses of soil extracts at the various exposure times revealed methyl eugenol as the only radiolabeled compound. It is possible that methyl eugenol could have been demethylated to form eugenol, thus losing the 14C-label; however, no eugenol was detected by either GC or TLC analyses.

Conclusions:
Methyl eugenol dissipated rapidly from soil with a halflife of ca. 6 h at 32ºC and 16 h at 22ºC.

Executive summary:

Methyleugenol was tested for persistence in soil using Lufkin fine sandy loam (Bull et al. 1970). The experiments were performed at 22ºC and 32ºC. 100 g of soil was mixed with 15 mL H20 in a beaker; then 2 mL of a hexane solution containing 10 mg of test substance were distributed uniformly over the soil surface. At 0, 24, 48, 72 and 96 h post-treatment, triplicate samples of this preparation were analyzed by GC for determination of the content of test susbtance.Methyl eugenol dissipated rapidly from soil. At 32ºC, 98% of the material was lost from soil within 96 h, and 81% was lost after 96 h at 22ºC. Methyl eugenol had a halflife of ca. 6 h in soil at 32ºC and a halflife of 16 h at 22ºC.

Description of key information

Supporting study: Test for persistence in soil using Lufkin fine sandy loam (Bull et al. 1970). Methyl eugenol dissipated rapidly from soil with a halflife of ca. 6 h at 32ºC and 16 h at 22ºC.

Key value for chemical safety assessment

Half-life in soil:
16 h
at the temperature of:
22 °C

Additional information