Based on their keen smell

May 31, 2007 12:46 GMT  ·  By

Balkan wars in the '90s left a "hard" inheritance: the landmines. Croatia, Bosnia-Hercegovina and the other countries of the former Yugoslavia, were intensively mined.

Over 1,000 sq km (380 sq miles) of Croatian countryside is infested by the mines. About 250,000 mines are still under ground, and made about 100 Croat victims since 1998.

A new biological method to detect unexploded landmines is being developed at Faculty of Agriculture, Zagreb University in Croatia: honey bees. "We started this because our citizens are exposed to serious risks with mines," said Professor Nikola Kezic.

The standard method of mine removal is a slow and very expensive process, which is not 100 % effective: even after the de-miners have finished their job, there may still be some mines in the soil.

Kezic wants to employ honeybees to detect the explosives that are missed by the de-mining teams. The bees are trained by feeding them on points where the soil immediately around has been impregnated with explosive chemicals (like TNT), based on the bees' keen sense of smell and their learning ability to connect the smell of explosives with food.

So far, this has proved to work. "Training the bees takes only three or four days." said Kezic. Bees are taken out of the colony and tested to see their reaction to extracts of explosives. "This year our work is to increase the bees' sensitivity to the smell of TNT," said Kezic.

Still, it will take time before the system could be considered reliable enough to actually be used. Colonies of trained bees can be released in a de-mined area, and their activity followed with a heat-sensitive camera. The insects would be expected to settle on soil zones that smell of explosives. If the area where no landmine was found earlier, the de-mining team will check to ensure they have not missed one.

If this method proves cheap, reliable and easily available, it could be employed by de-mining teams all over the Balkans. In African countries, Gambian giant pouched rats are employed to find mines. Dogs also can be employed, but due to their weight, they can trigger the mines.