Library and archive material contaminated by radiation

Toru Kibe <torukibe [at] gmail__com> writes

>I am a Japanese book conservator. As you know, the northeast area of
>Japan was struck by the huge tsunami and nuclear accident. So many
>library and archive materials are lost and damaged. We are now
>looking for an approach to the preservation and conservation of
>these materials, especially radiation contaminated material.

Unless the material was at the centre of the nuclear disaster in the
nuclear plant itself, the radiation levels of any contamination are
likely to be quite low. The levels may be above "standard
background" level, but there are many places around the world where
the background radiation level are dozens of times standard
background level just because of the natural composition of the
minerals in the rocks and soil (and people have been living there
for millennia). The radiation levels from contaminated material is
likely too low to harm the material itself (very high levels might
slightly increase aging of materials, or mean there is sufficient
foreign material present to rate as "dirt").

The main issue with contamination is human health, specifically of
anyone accessing the material. Ingestion of traces of contamination
by mouth or breathing is the main concern here. Check the radiation
levels of the material with a Geiger counter. If it is not
significantly above standard background or the normal background
levels for the area, then there is probably nothing to worry about.
If you actually get a reading high enough to be of concern, then
anyone handling the material should take contamination precautions
(gloves, protective clothing/tyvek suit, respirator, no eating or
drinking in the area, etc.).

Protective clothing may need to be disposed of as "active waste"
after use if contamination levels are high, so disposable clothing
is preferred. The material should be sealed to prevent spreading the
contamination around (sealing in plastic should be sufficient),
after completing any necessary preservation treatment. If the
radiation levels are very high (unlikely), you may want to enclose
the material in a lead enclosure, or with a lead sheet in front of
it. Don't bother with the lead if the levels of radiation are low,
the toxicity of lead becomes a greater health hazard than the
radiation at very low levels.

On the plus side, the isotopes that compose the contamination are
likely to be ones with relatively short half lives, and the
radiation levels will decay to safe levels relatively quickly (days,
months, years, or even decades, but not likely centuries), so
continue to monitor the radiation periodically with a Geiger
counter, and remove the radiation precautions when the readings fall
to safe levels ("safe" may still be dozens of times standard
background level).

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain
Private Bag 92018
Auckland 1142
New Zealand
+64 9 306 7068


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                  Conservation DistList Instance 24:45
                  Distributed: Monday, March 28, 2011
                       Message Id: cdl-24-45-002
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