In the fields above San Gabriel in the mountains of northern Ecuador, a farmer with a backpack sprayer applying a pesticide to a potato crop is a common scene.

This scene, repeated daily on millions of farms throughout the developing world, poses a dilemma. It has polarized two important interest groups—environmentalists and agriculturists—and locked them in a bitter policy struggle.

In recent years, the debate on the sustainability of modern agricultural technology has increasingly focused on health and environmental issues. Concerns include depletion of natural resources, soil erosion, water pollution, deforestation, and contamination and poisoning caused by agricultural chemicals. The dilemma is how to balance agricultural development that includes the use of chemical inputs with demands for sustainable agriculture that is environmentally sound.

The issue is not just an academic question in Ecuador. Environmental groups there claim that potato farmers who use chemical pesticides are poisoning the environment. Based on these arguments, the environmental lobby has recommended banning numerous pesticides, including insecticides used to control the Andean potato weevil, the most devastating potato pest in the Andes. The farm lobby opposes this proposition.

Classic agriculture-environment conflict

Charles Crissman of CIP says that the Ecuadorian situation is a classic agriculture-environment conflict—the trade-off between agricultural production and environmental quality. With powerful interests on both sides, the issue will in all eventuality be decided in the political arena. Unfortunately, issues such as these are characterized by a lack of solid information on the size of potential trade-offs. For example: how much agricultural production must be given up to improve the environment or health? Politicians, who intuitively understand trade-offs, frequently operate without the information needed to back-up their decisions.

Addressing the environment-agriculture dilemma, the CGIAR is encouraging its member institutions to incorporate issues of sustainability into their research agendas. One response of the CGIAR centers has been to initiate research programs based on agroecosystems rather than on commodities alone.

In a research project headed by Crissman, the Center looked at yield and environmental and health impacts of pesticide use in potato production in the San Gabriel area. Besides shedding light on the ongoing Ecuador debate, the research is valuable for the Center, whose principal charge is to generate improved agricultural technologies, especially for poor farmers.

"New technologies can increase crop yields and farm incomes, but they can also have indirect or 'off site' impacts," Crissman says. "These latter impacts have become more important in evaluating new technologies and returns to research. For example, the largest benefit of integrated pest management (IPM) may not be fewer crop losses, but rather reduced contamination from less insecticide use."

Pesticide impacts

For the study in northern Ecuador, CIP scientists are working with counterparts from Ecuador's Catholic University, Montana State and Cornell universities in the United States, and McMaster University in Canada. Together they have designed a research method to provide an extensive analytical backdrop combining field-level relationships among farm management practices, the environmental characteristics of the land, and nonpoint pollution with impacts on human health. To be useful for policy analysis, the research methodology was designed to make a link between human health and the physical changes in environmental and resource quality attributable to agricultural practices.

The basic premise was that a well-known economics tool, benefit-cost analysis, could provide the framework to combine disciplinary models and data for policy analysis. A research team of soil scientists, epidemiologists, medical doctors, and agricultural economists applied the model in research that focused on groundwater pollution and farm worker poisonings.

An eight-fold increase in pesticide poisonings

Working in two adjoining watersheds in San Gabriel over a two-year period, researchers found that when potato farmers used combinations of chemical pesticides to control the Andean weevil and late blight, the amount of pesticides leaching out of the potato root zone was well below World Health Organization standards, even in worst-case scenarios. The combined effects of the high organic matter content of the volcanic soils, the short half-life of the active ingredients of the compounds used, and the light rainfall pattern moved the chemicals slowly through the soil, where they bound with the organic matter and degraded relatively rapidly.

The experimental results thus refute the arguments of the environmental lobby. In potato production similar to that of the study site—which includes most of Ecuador—environmental contamination from pesticides is minimal.

These results, however, fail to consider health impacts. Following up on poisonings reported by health care providers, the research team found that there was an eightfold increase in the rate of reported pesticide poisonings in the San Gabriel region—from 21 cases per 100,000 persons to 171 per 100,000. Further follow-up showed that the majority of these cases were men engaged in pesticide spraying. Tests of San Gabriel spray operators showed a consistent pattern of chronic rash and central nervous system damage from pesticide residues absorbed through the skin, specifically the hands.

Results from computer models shed considerable light on the Ecuador debate. "Pesticide use in potato production is not contaminating the environment," Crissman says, "but is poisoning a large segment of the rural population. The policy prescriptions are thus markedly different for these different outcomes. Instead of an environmental policy outcome such as water quality regulations, what is recommended are public health policies such as health education programs."