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- Forget fatal fungi and diabolical booby traps. Some of
Egypt's ancient monuments harbour a more insidious threat--they contain
high levels of the radioactive gas radon.
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- Jaime Bigu of Laurentian University in Sudbury, Ontario,
and researchers with the Atomic Energy Authority of Egypt in Cairo looked
at seven ancient monuments. Three had potentially hazardous radon concentrations.
The highest level--5809 becquerels of radon per cubic metre--was in the
Sakhm Khat Pyramid at Saggara, south of Cairo. Nearby, there were 1202
becquerels per cubic metre in the Abbis Tunnels and 816 becquerels per
cubic metre in the Serapeum Tomb.
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- Radon is produced by the decay of uranium in the ground
and in rocks used to build the monuments. High levels increase the risk
of lung cancer. Britain's National Radiological Protection Board, for example,
recommends that homes with radon concentrations above 200 becquerels per
cubic metre should install fans to disperse the gas.
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- In the Journal of Environmental Radioactivity (vol 47,
p 245), Bigu recommends improving ventilation at the three sites. Guides
currently work inside the monuments for around four hours a day. But if
their working hours doubled they would exceed the international safety
limit for workers of 20 millisieverts a year.
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- Visitors are not at risk. But concentrations of radon
would have been much higher when the sites were opened. "The high
radon levels may not have caused the Curse of Tutankhamen," says Murdoch
Baxter, editor of the Journal of Environmental Radioactivity, "but
it probably won't have done those early Egyptologists much good. (From
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