300mila case radioattive in Svezia per via dei mattoni (5 dicembre)

Il problema del Radon non sempre è di origine "naturale". Più spesso capita che si sia costruito utilizzando materiali contenenti uranio. Sarebbe interessante sapere in Italia quante e quali sostanze radioattive vengono impiegate nelle costruzioni.

SSI news 1/1995
Blue Concrete
In Sweden some 300.000 dwellings have walls of lightweight concrete blocks containing uranium.
http://www.ssi.se/tidningar/PDF/lockSSIn/SSIn_1_95.pdf


Anche in Canada, lo stesso problema:

Radioactive Homes
http://ccnr.org/uranium_deadliest.html#home

At Elliot Lake, about a ton of ore is required to extract two pounds of uranium. Huge quantities of pulverized rock (called uranium tailings) are left over from the milling process. The tailings contain 85 per cent of the original radioactivity in the ore: they contain thorium-230, radium-226, and all the other uranium by-products. The tailings also give off at least 10,000 times as much radon gas as the undisturbed ore. (When radon gas is produced inside hard rock, it has little chance to escape; but when the rock is pulverized, radon escapes easily.)

In the Southwest U.S. and in Port Hope, Ontario, many homes and schools were built using the sand-like uranium tailings as construction material. As a result, some of the buildings ended up with levels of radon gas and radon daughters even higher than those permitted in the mines. Similar (though less severe) problems arose in Florida and Newfoundland when phosphate tailings were used for construction, and in Oka and Varennes (just outside of Montreal) when other mine tailings were used in construction. In each case, the original ore was rich in uranium, so the tailings gave off high amounts of radon.

In 1975, St. Mary's School in Port Hope was evacuated because of extraordinarily high radon levels. Radioactive fill had to be removed, at public expense, from hundreds of homes and gardens. Even today, there are over 200,000 tons of radioactive debris lying about the town of Port Hope in open ravines, easily accessible to children and to pets. Eldorado Nuclear Limited, the crown corporation whose radioactive wastes had been generously donated to the eager townsfolk for construction purposes many years earlier, has recently promised -- under the prodding of the Ontario Environment Department -- to finish cleaning up the mess sometime during the next few years.