Microbiological activity in PEG tanks

I am working on a project on microbiological activity (fungi,
bacteria) in large scale PEG-conservation-tanks for waterlogged
woods. Several of the tanks in my research-project are heavily
attacked with aggressive growth of fungi on the top of the solution.
The tanks have practically the same conditions, are constructed in
the same way, but some small fluctuations in temperature do occur.

(Recently there was a change in the PEG, from PEG 400 to PEG 4000 in
all the tanks, and another tank which previously did not have much
growth on top of the solution, started to blossom, and others
regressed.)

During my courses I have been in contact with some conservators with
great experience in this field and they have given me the impression
that the phenomena does not exist. My first question is now: Is it
really so, or can it be that as long as the smell, dirt and dust
from the microbiological growth does not affect the conservator he
will ignore this 'problem'? My second and third question: Does the
microbiological growth affect the treatment-results in any way--are
the PEG-molecules and/or the wood's lignin and cellulose subjected
to microbiological metabolism? And how can microbiological activity
be avoided, with as little use of chemicals as possible in the
preliminary treatment-phase and during treatment.

I am grateful for answers from any with experience in this matter.

Morten Jerstad
Student in conservation
Oslo, Norway.


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                  Conservation DistList Instance 13:43
                Distributed: Wednesday, February 9, 2000
                       Message Id: cdl-13-43-012
                                  ***