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Environmental fate & pathways

Biodegradation in soil

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Administrative data

Endpoint:
biodegradation in soil
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
acceptable study meets basic scientific principles Hypothesis and analogue approach for read-across: This substance (S-Ethanol, composition 2) has degree of ethanol purity between 76 - 82%. Methanol is the main impurity of the target substance (conc. 13-14 %), and considered the major driver for adverse effects based on its properties and relative quantity in the substance. Therefore, testing of the substance itself was considered unnecessary. Instead the available REACH registration data of ethanol and methanol is used in order to update the chemical safety assessment of this substance. Other impurities of this substance are taken into account for self-classification, but there is no need to consider their properties in hazard assessment because of low concentrations (see IUCLID section 1.2; composition 2).

Data source

Reference
Reference Type:
publication
Title:
Biomineralization rates of 14C-labelled organic chemicals in aerobic and anaerobic suspended soil
Author:
Scheunert, I. et al.
Year:
1987
Bibliographic source:
Chemosphere 16(5): 1031-1041

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The formation of CO2 from 14C-labelled methanol in aerobic and anaerobic suspended soil was determined.
GLP compliance:
not specified
Test type:
laboratory

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Methanol
- Analytical purity: >99%
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
no data
Radiolabelling:
yes

Study design

Oxygen conditions:
aerobic/anaerobic
Soil classification:
not specified
Soil properties
Soil no.:
#1
Soil type:
Alfisol
% Clay:
17
% Silt:
75
% Sand:
8
pH:
7.3
Details on soil characteristics:
SOIL COLLECTION AND STORAGE
- Soil preparation (e.g., 2 mm sieved; air dried etc.): air-dried and sifted to a particle size of 0.125 mm


PROPERTIES OF THE SOILS (in addition to defined fields)
- organic matter: 2.45%
Duration of test (contact time)
Soil No.:
#1
Duration:
5 d
Initial test substance concentration
Soil No.:
#1
Initial conc.:
15 other: µg
Based on:
other: 15 µg methanol was added in aqueous solution or suspension to 50g soil in 150 mL water
Parameter followed for biodegradation estimation:
CO2 evolution
Experimental conditions
Soil No.:
#1
Temp.:
35°C
Details on experimental conditions:
EXPERIMENTAL DESIGN
- Soil preincubation conditions (duration, temperature if applicable): 50 g soil and 150 mL water were equilibrated for 7 days at 35°C in oxygen or nitrogen. Then 14C-labelled methanol was added.
- Soil condition: air dried
- Soil (g/replicate): 50
- Test apparatus (Type/material/volume): 1 L wide-mouth bottles, with gas inlet and outlet and two valves
- Details of traps for CO2 and organic volatile, if any: 15 mL absorption tubes, the first being filled with 15 mL ethyleneglycolmonomethylether for trapping organic volatiles, the second with 15 mL alkaline scintillation liquid (330 mL phenethylamine, 220 mL methanol, 400 mL toluene, 50 mL distilled water, and 7g Permablend III, Packard) for trapping 14CO2


Test material application
- Volume of test solution used/treatment: 50 g soil and 150 mL water with 15 µg methanol in aqueous solution
- Application method (e.g. applied on surface, homogeneous mixing etc.): mixing


3. OXYGEN CONDITIONS (delete elements as appropriate)
- Methods used to create the an/aerobic conditions: incubation in oxygen or nitrogen


5. SAMPLING DETAILS
- Sampling intervals: first measurement of 14CO2 and volatile organic substances after 5 days, further determinations in dependence on the persistence of the compound. Determination of radioactivity left in the aqueous phase at the end of the experiment

Results and discussion

% Degradationopen allclose all
Soil No.:
#1
% Degr.:
53.4
Parameter:
other: CO2 evolution, aerobic condition
Sampling time:
5 d
Soil No.:
#1
% Degr.:
46.3
Parameter:
other: CO2 evolution, anaerobic condition
Sampling time:
5 d
Soil No.:
#1
% Degr.:
15
Parameter:
other: 14C in soil-water suspension, aerobic condition
Sampling time:
5 d
Soil No.:
#1
% Degr.:
13.6
Parameter:
other: 14C in soil-water suspension, anaerobic condition
Sampling time:
5 d
Transformation products:
not specified
Identity of transformation products
No.:
#1
Reference
Reference substance name:
Unnamed
IUPAC name:
no data
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified
Details on results:
no details
Results with reference substance:
no data

Any other information on results incl. tables

Degradation of methanol was higher under aerobic than anaerobic conditions. The mineralization rates are minimum values since mixtures were not acidified to release 14CO2 bound as carbonate, and 14CO2 assimilated to natural products and incorporated into biomass could not be determined. Furthermore, 14CH4 formed possibly under aerobic conditions was not determined.

Applicant's summary and conclusion