• In Brazil, 28 per cent of farmers in Santa Catarina state say they have been poisoned at least once and in Parana state some 7,800 people were poisoned between 1982 and 1992.
• In Egypt, more than 50 per cent of cotton workers in the 1990s suffered symptoms of chronic pesticide poisoning, including neurological and vision disorders.
• In China, 42,800 new cases of pesticide poisoning were reported in 1994, including 3,900 fatalities. Many were said to be victims of homemade cocktails marketed illegally.
Aquaculture is a new and rapidly growing industry and it has created a new concern in pesticide use. Sea lice often attack farmed salmon, causing scarring, infection and, sometimes, death. To eliminate them, the salmon are confined by a closely drawn net and surrounded by a tarpaulin. Dichlorvos, which is the active ingredient in the familiar household pesticide strips, is then added directly to the water. At present, the environmental effects of this pesticide are unknown. The pesticide is toxic to lobster larvae, however, and it may have other undesirable properties.
Pesticides can adversely affect wildlife through changes in the food web, direct and indirect poisoning, chemical "bioconcentration", and habitat changes. And their harmful effects may show up in animals, which have no direct relationship to the original pest. In the 1960s, wildlife biologists were puzzled when the gannet population on Bonaventure Island, Quebec, began to shrink. The shells of the gannets' eggs were too thin to protect the embryos. Only after the eggs had been analysed did the scientists identify the culprit DDT, which had been bioconcentrated through higher levels of the food web. Populations of other predatory birds such as ospreys, eagles and peregrine falcons also declined when the birds accumulated DDT through their food.
Many of the birds that nest in Atlantic Canada are migratory.
