杏吧原创

CLOVES are legendary for their power to numb toothache and, unlikely as it
seems, the aromatic spice looks destined for a role in removing asbestos, the
fibrous mineral once used routinely to fireproof buildings.

Alternatives to conventional techniques are desperately needed. Usually
buildings have to be sealed off during mechanical removal, with air pressure
differentials imposed to stop the deadly fibres escaping into the air. Workers
must wear protective clothing to avoid breathing in the lethal fibres, which
cause lung cancer and mesothelioma鈥攁 cancer of the lung cavity.

Even with these precautions, fibres can linger in the air for more than four
years, according to research by the US Environmental Protection Agency.

Now Italian chemists have neutralised the lethal fibres using an extract of
cloves. When the liquid extract touches the surface of asbestos, it instantly
hardens into a polymer similar to lignin, which gives wood its strength. All the
potentially hazardous fibres are harmlessly embedded in the polymer and can鈥檛
float off into the air.

Bice Fubini and her colleagues in the department of inorganic chemistry at
the University of Turin used a combination of hydrogen peroxide and eugenol, a
phenol-like chemical found in cloves鈥擡ugenia caryophyllata.
Working with colleagues Ivana Fenoglio and Maura Tomatis, Fubini proved that the
treatment works on blue asbestos or crocidolite, one of the most dangerous forms
of the mineral. 鈥淲e knew already that eugenol would polymerise on various
silicates, so we thought we鈥檇 try it on asbestos, which is a similar silicate,鈥�
says Fubini. They鈥檙e confident it will also work on the white (chrysotile) and
brown (amosite) forms.

As an added bonus, the polymer also mopped up the 鈥渇ree radical鈥� chemical
complexes that can lurk on fibres and damage DNA, potentially turning cells
cancerous.

The polymer has stayed stable since the experiment, the team report. 鈥淚t
could probably be buried without much danger to people,鈥� she says. 鈥淚t could
also possibly stay where it is in a building, but this would need to be tested
absolutely to make sure it would be safe.鈥�

The team hopes that a company will step in to commercialise the idea and work
out how best to apply it. 鈥淚t must be adapted to practical purposes,鈥� she says,
with eugenol either extracted from cloves or synthesised.

From next June, all owners of business premises in Britain will have to make
safe any asbestos in their buildings. 鈥淚f something seals the asbestos, it鈥檚 a
far more permanent solution,鈥� says Terry Jago, chief executive of Britain鈥檚
Asbestos Removal Contractors Association.