TTHE pesticide DDT was banned in the United States in the 1970s and its export was banned in the 1980s, but it and others made with similar chemicals continue to be the most widely used pesticides throughout the developing countries.
Why are DDT and its related pesticides still being used when there is so much well-documented evidence against them?
One reason is that the World Health Organization continues to recommend DDT for use in eliminating malaria-carrying pests.
The United Nations Environment Program, however, has been warning for decades that DDT contributes to the resistance of malaria-carrying insects. In one study conducted by the UN Environment Program and the Central American Research Institute for Industry, resistance of malaria-carrying pests to DDT was found to have increased from 58 percent to 86 percent over a two-year period in Guatemala's cotton-growing areas. As a result, Guatemala had to spend $1.6 million more on malaria control the following year.
Moreover, studies by international agencies and academic and nonprofit groups have shown that the soil and food chain are heavily contaminated with DDT residues throughout Africa, Asia, Central and South America, and the South Pacific, with alarming levels of DDT residues showing up in mothers' milk.
A recent study by the Punjab Agricultural University in India found that babies in the cotton-growing region of the Punjab were consuming 24 times as much DDT residue as is considered safe.
Similar studies by the Pesticides Action Network and Greenpeace have shown extensive contamination of the food chain in the South Pacific where, in addition to its use as a pesticide, DDT is often used to kill fish.
The contamination of mothers' milk in many developing countries has prompted the United Nations Environment Program to take the unusual initiative of recommending the use of infant formula in these regions, even if that means risking that the infant formula will not be prepared as safely as it should be.
The soil and ground water are also heavily contaminated in regions where DDT is still being used. Persistent use of DDT and its related chemicals can thoroughly undermine the productivity of the soil over time by destroying the microorganisms and nutrients that nourish crops. This not only decreases agricultural productivity, but, by weakening the land, makes it vulnerable to desertification.
That calls into question the primary explanation given for DDT's continued use, which is its low cost. The short-term benefit of its low sale price is also offset by a loss of export profits for the countries that use it. Hundreds of thousands of pounds of beef and dairy products from Central and South America have been rejected for import by the US, for example, because they contained DDT residues far above acceptable levels.
If the use of DDT is going to stop, it will require more than laws banning its export from the developed nations. It will require passage by developing countries of legislation banning its import and use within the developing countries, and it will require pressure from international agencies and government and aid organizations to discourage its sale and application. These agencies could:
* Require that a country ban DDT before it is eligible to get funding for sustainable agriculture methods.
* Encourage alternatives to pesticide use - such as integrated pest management - wherever possible.
* If necessary, subsidize the cost of newer, less toxic, and more easily biodegradable pesticides if such chemicals appear indispensable to providing adequate agricultural production for the population.
Converting from dependence on DDT should become a central feature of aid projects worldwide.
Without pressure from the aid organizations and the media, the situation is unlikely to change. While grass-roots environmental organizations exist within many developing countries, they are frequently stymied by unresponsive and corrupt governments in their efforts to achieve policy reforms.
If measures are not taken to discontinue the wide use of DDT in the developing world, however, the efforts of international aid agencies to encouraging sustainable agriculture in these regions will be undermined by long-term soil depletion.
The menace of DDT can be removed from the ecosystem only by concerted action from the entire global community, and such action is needed now. The Opinion/Essay Page welcomes manuscripts. Authors of articles we accept will be notified by telephone. Authors of articles not accepted will be notified by postcard. Send manuscripts to Opinions/Essays, One Norway Street, Boston, MA 02115, by fax to 617 -450-2317, or by Internet E-mail to OPED@RACHEL.CSPS.COM.