By Dominic Bailey
BBC News Online
Danish scientists say they have developed a genetically modified plant that will detect unexploded landmines.
The green cress turns red when it detects explosives (Image: Aresa)
There are believed to be about 100 million unexploded landmines around the world, posing a daily threat to life.
Plants developed by Copenhagen firm Aresa Biodetection are said to turn from green to red when they come in contact with explosives in the soil.
But some international mine clearing firms have raised concerns about how practical the plants would be.
At least 26,000 people are killed or injured by mines every year.
Aresa's aim is to plant its GM plant - an altered thale cress - in landmined areas. Scientists say that within three to six weeks it will change colour in areas where roots come in contact with nitrogen dioxide (NO2) evaporating from explosives in the soil.
Aresa Chief Executive Simon Oestergaard said the project was still in its early days but it had great potential for land that could be used for different agricultural activities.
"We don't think our invention will completely replace other methods," he said.
Landmines are traditionally located by a number of methods including the use of sniffer dogs, heavy machines or metal detectors. The mines can then be carefully removed.
Aresa says the seeds could be sown by using an off-the-shelf pump or a crop-spraying plane.
Carsten Meier, of Aresa, told the BBC that they were working with the Danish army and hoped that field trials in live-mine areas could take place within two years.
Millions of unexploded mines need to be cleared (Image: Sean Sutton/MAG)
"We have to convince people who are actually clearing mines that this system is reliable," he said.
Geir Bjoersvik, senior adviser on landmines for Norwegian People Aid, said the development was likely to be "a welcome addition to current methods if successfully passing further testing in areas of operation".
"This is a promising development in the efforts to find a safe and cost-effective solution to detect mines," he said.
But the Halo Trust, the Scottish-based international mine-clearing charity with 5,500 deminers and 120 heavy mine-clearing machines around the world, has raised some concerns about the project.
Director Guy Willoughby said he was worried that the fresh growth could attract livestock into the mined areas.
He also said planting the seeds and the follow-up clearance of identified mines would have to add up to less than Halo' s current cost of 40 pence per square metre.
Bob Gravett, senior technical advisor to the Mines Advisory Group, was also sceptical: "Over the last couple of years we have had bees that can detect mines, then rats and now cress."
He said relying on the NO2 seepage would not guarantee that all the mines had been detected, as some are specially sealed.
"The biggest task in mine clearing is proving that there are no landmines in an area," he told BBC News Online. "This is not going to give you any more than an indication and we already have that, from the local population."
He said land would still have to be totally cleared afterwards to be declared safe.