Biotech to help clear the curse of landmines
OF ALL the weapons of warfare invented by man, the most evil is the atom bomb. It kills and maims millions, and disables their children and grandchildren. No amount of justification — that it is a deterrent, it places a nation among the mightiest in the world, and all that — can wash off its evil. Rank number two must be given to landmines. These are innocuous-looking objects that are strewn all over land; when someone walks over them or handles them, they explode, killing or maiming the unfortunate victim.
A landmine is easy to make and easy to bury or scatter about in camouflage. It contains nitrogenous compounds, usually trinitrotoluene (TNT), nitroglycerine (dynamite) or ammonium nitrate, mixed with an absorbent substance like kieselguhr and explodes when pressed hard. Some landmines also contain metal dust or filings, which, upon explosion, lodge in the victim's body causing great pain. Walk over one of these, or handle them unwillingly and you can be hurt.
As can be guessed, making landmines needs no advanced degree in chemistry or engineering; many are made in cottages and ramshackle garages. More often than not, army ordnance factories make them by the thousands. Warring armies sow them on fields and borderlands. Landmines have turned out to be the major weapon of many poor nations. When the Yugoslav union broke up, the warring factions, in particular Bosnia/Herzegovina, planted as many as six million landmines. This amounts to 150 mines per square mile, or one mine per inhabitant.
Croatia did the same, with three million of them — 130 per square mile and two mines per three persons. When the Khmer Rouge ruled over Cambodia, they planted six million of them all across the country. After the war is over, what is left behind? Millions of them that maim unsuspecting farmers or children.
It is estimated that almost every family in that country has at least one person who has lost a limb, thanks to the landmines planted during the internal civil war that has long since ended. The effects are being felt even now, and will be for a generation or so more, if the landmines are not cleared.
Since landmines are the bombs of poor nations, many countries in Africa, Asia and the Middle East have been using them. Egypt, Iraq, Iran, Afghanistan, Cambodia, Vietnam, Ethiopia, Eritrea, Somalia, Sudan, Rwanda, Angola, Mozambique — the list runs as the Atlas. India and Pakistan are not far behind.
India's stockpile
Amnesty International, and the International Campaign to Ban Landmines (ICBL) point out that thousands of acres of farmland along the Indo-Pak border are contaminated with antipersonnel and antitank mines. These are the results of mine-laying by the Indian Army since December 2001. The ICBL Report says that India maintains a stockpile of 4-5 million antipersonnel landmines, the fifth largest in the world.
And the majority of these are believed to be low-metal-content M-14 blast mines, which are hard to detect and hence prohibited by the Convention on Conventional Weapons (CCW) Amended Protocol II, to which India is a party as of 1999. Recent reports suggest that mine laying by both India and Pakistan has stopped, and India has started clearance. This is somewhat heartening to hear, but what is sad is that India is not a signatory to the 1997 Land Mine Ban Treaty of Ottawa.
The problem of clearing landmines stares in our faces with its enormity in numbers and cost.
There are anywhere between 100-120 million landmines across the world, waiting to be cleared so as to make living safe for us and our children. Making a landmine costs anywhere between $3-15, while clearing a laid one can cost as much as $1000 per unit, the Red Cross estimates. It was to tackle this scourge that an indefatigable American lady called Jody Williams coordinated the international campaign to ban landmines (ICBL) since the early 1990s.
The ICBL works to ban and clear landmines, persuade governments to stop using them and to engage in clearing already laid ones. Thanks to this campaign, the Ottawa Mine Ban Treaty was signed in 1997. In the same year, the Nobel Peace Prize was awarded to ICBL and to Jody Williams in equal part.
The scientific problem that challenges us is how to detect landmines so that they can be removed. A vast range of technologies and hundreds of millions of dollars have been spent. Yet, there is still no operationally satisfactory solution.
Metal detector array
The Improved Landmine Detector Project (ILDP) of America produced a tele-operated multi-sensor vehicle-mounted detector for low-metal-content, and non-metal landmines. The ILDP has a metal detector array based on electromagnetic induction (EMI), an infrared imager (IR), a ground penetrating radar (GPR) and a thermal neutron analysis (TNA) detector. Each of these provides information on a chosen property of the landmine. EMI reports anomalies in electrical conductivity, GPR detects dielectric anomalies and TNA measures the nitrogen content. In effect, what the ILDP device does is analogous to what a sophisticated pathology lab does with our body using ultrasound, X-rays and MRI. As can be guessed ILDP runs into a great sum of money, the kind that India, Cambodia or Iran cannot easily deploy over thousands of acres.
Can biotechnology help? Hopefully biotech is plantable on the soil, can detect or utilise the material contained in the mine and thus disable it over time. Recall how Dr. Anand Chakrabarti came out with an oil-eating microbe that could, in principle, eat off barrels of crude oil spilt over when a ship capsized. Could we engineer bugs that would eat away landmines? Great idea, but that would mean leaving the minefields unused for quite some time, so as to allow the microbial clearance to occur. This would, in many countries that need farmlands to feed themselves, be a luxury they cannot afford. A better biotech method would be detection, which could then lead to physical removal. Danish scientists at the University of Copenhagen and the firm called Aresa Biodetection have made such an advance in the bio-detection of landmines. They have used the plant thale cress (Arabidopsis thaliana) as the detecting device.
Arabidopsis is to the botanist what E. coli is to the microbiologist, the flatworm C. elegans is to the cell biologist, or the fruit fly drosophila is to the geneticist. He can play with the genes of the plant, add or subtract genes at will and thus engineer the plant to do specific tasks.
Plant as sensor
Arabidopsis naturally changes colour under certain conditions. But what these researchers did was to manipulate the genetic switch so that the chosen variety changes colour when its roots sense nitrogen dioxide.
It is this oxide that is produced from the nitrogenous explosives contained in landmines. The group has tried planting this variety of Arabidopsis in soils containing TNT, and in boxes containing landmines, with success. Do we thus have a solution at last? "Perhaps, perhaps not" say landmine experts. They point to the cost of defoliating landmines before sowing the plants, and watering in arid climates. But perhaps some of these can be overcome through better manipulation of the plant.
To be sure though, this adds one more to the arsenal against landmines, besides other `biotech' ways such as using honeybees, sniffing dogs and such, and it is an improvement over the chemical method that uses a special polymer that changes colour when it binds to TNT and related compounds.
D. Balasubramanian
dbala@lvpei.org
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