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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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biodegradation in water and sediment: simulation tests
Type of information:
experimental study
Adequacy of study:
other information
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: There are no information on the test substance and no reference to any guideline in this non-GLP experiment.

Data source

Reference Type:
Degradation of different aromatic compounds by methanogenic consortia from Saale river sediment acclimated to either o-, m- or p-cresol.
Kaminski U., Kuschk P, Janke D
Bibliographic source:
J. Basic Microbiol. 30 (4) : 259-265

Materials and methods

GLP compliance:

Test material

Details on test material:
no data

Study design

Oxygen conditions:
Details on inoculum:
other: methanogenic consortia acclimated to either o-, m- or p-cresol

Results and discussion

Details on results:
Enrichment studies indicated all 3 cresol isomers to be degradable under strict anaerobic (methanogenic) conditions, after an acclimation period of 12 to 40 days depending on the isomer. After this, the rates of substrate removal were at least twofold increased compared to fresh (non-acclimated) sediment and methane was produced according to the theory. The enzyme systems initiating methanogenic degradation of the different cresol isomers were shown to present a narrow substrate specificity.
Among the cresol-acclimated consortia, only the p-cresol-acclimated one proved able to remove salicylic acid within 24 days of incubation.
This process unexpectedly occurred without any lag and was due to decarboxylation of the test substrate to phenol. In contrast, Kuhn et al. hypothesized reductive dehydroxylation (yielding benzoic acid as the intermediate) to be the initial reaction in degradation of salicylic acid by aquifer slurries under methanogenic conditions. Interestingly, the o-cresol-acclimated consortium from Saale river sediment failed to deal with salicylic acid suggesting that this compound was not an intermediate in methanogenic degradation of o-cresol.

Applicant's summary and conclusion

Submitter : this study indicates that salicylic acid is not readily biodegradable in anaerobic sediment. Especially we don't agree with the absence of lag in the p-cresol-acclimated consortium, as the graph shows a 4-day lag phase.