Fatty acids, C16-C18 (even numbered) and C18 (unsaturated) and Fatty acids, C16-C18 (even numbered) and C18 (unsaturated) methyl esters

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

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

Reference Type:

publication

Title:

Unnamed

Year:

1995

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Similar to official guideline, some parameters changed

GLP compliance:

no

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

fatty acids, soya, methyl esters

IUPAC Name:

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:

aerobic/anaerobic

Duration of test (contact time)

Soil No.:

#1

Duration:

ca. 7 d

Initial test substance concentration

Soil No.:

#1

Initial conc.:

ca. 0.8 mg/kg soil d.w.

Based on:

test mat.

Results and discussion

% Degradation

Key result

Soil No.:

#1

% Degr.:

>= 99 - < 100

Parameter:

CO2 evolution

Sampling time:

7 d

Transformation products:

no

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

Conclusions:

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.