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Environmental fate & pathways

Biodegradation in soil

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biodegradation in soil: simulation testing
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No guideline followed, many details about sample are missing, but the test is in any case good described and scientifically useful

Data source

Reference Type:

Materials and methods

Test guideline
no guideline followed
Principles of method if other than guideline:
Similar to official guideline, some parameters changed
GLP compliance:
Test type:

Test material

Constituent 1
Reference substance name:
fatty acids, soya, methyl esters
fatty acids, soya, methyl esters
Details on test material:
- Name of test material : Soy Diesel
- Composition: mixture of methyl esterifed long chain fatty acids (C18-C20)
- Supplier: Interchem Environmental, Incorporated, Leawood, KS, USA

Study design

Oxygen conditions:
Duration of test (contact time)
Soil No.:
ca. 7 d
Initial test substance concentration
Soil No.:
Initial conc.:
ca. 0.8 mg/kg soil d.w.
Based on:
test mat.

Results and discussion

% Degradation
Key result
Soil No.:
% Degr.:
>= 99 - < 100
CO2 evolution
Sampling time:
7 d
Transformation products:

Any other information on results incl. tables

Bacterial population increased of 4 orders of magnitude with the disapperance of fatty acids methyl esters. Control flask tests which contained only MSM and inoculum increased only two orders of magnitude.

Soy degrading isolates.

Nine isolates of aerobic soy degrading bacteria were obtained from Old Hickory Lake enrichments. All nine strains were identified as strains of Burkholderia cepacia based on physiological characteristics (Rapid ID). Four strains of soy degrading bacteria were isolated from Old Hickory Lake samples using anaerobic conditions with nitrate as the terminal electron acceptor. They were shown to also growaerobicallyon soy diesel, but were not further characterized biochemically.

Other data presented in this paper show that soy diesel can support the growth of bacteria with concomitant disappearance of FAMEs. It can be degraded under both oxic and anoxic conditions by the microbial populations found in freshwater and soil environments. An extended lag phase was observed in all experiments using natural samples or pure cultures which had not previously been exposed to soy diesel.

Applicant's summary and conclusion

FAMEs were reduced to undetectable levels by seven days in the aerobic freshwater and soil flask tests.
Appreciable degradation occurred by day 7 with complete disappearance by day 14 in anaerobic freshwater and soil flasks.
There also was a noticeable loss of FAME after 14 days in the sterile controls but no increase in microbial population.