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and chlordane. Pest resistance to these chemicals has resulted in a search for
more toxic products having less environmental permanence, such as the
organophosphates and the pyrethroids.
Although pesticides are designed to eliminate undesirable and harmful organisms
that damage crops, other living beings, including humans, are susceptible
to them to a varying degree, so that their use can constitute a public-health
problem. In 1973, the World Health Organization (WHO) estimated that there
were over 500 000 pesticide poisonings per year in the world, with a death rate
of 1%. In developing countries, it is estimated that 375 000 severe cases occur
annually, with 10 000 deaths; this corresponds to about one case per minute
and one death per hour (Henao and Carey 1986). Some examples are:
In Chinguira (Colombia), 600 cases of poisoning by parathion and 88
deaths were reported (Vargara 1984);
In Brazil, out of 5 000 workers examined, 900 showed reduced cholinesterase
levels (Zanaga et at. 1984); and
Also in Brazil, of 1107 workers examined, 173 suffered from poisoning,
41.6% due to organophosphates (Zanaga et al. 1984).
The Instituto Nacional de Salud Ocupacional (INSO) began taking action in
this field in 1976. In 1978, 11 farms were visited; of the 237 workers seen, 62%
showed some level of poisoning, 6.7% of the cases were children. In the valleys
of Tarija in 1977, 43% of those examined showed signs and symptoms of
poisoning. In the Rio Abajo valleys, 14 deaths in 1977 were due to pesticide
poisoning. During the period 1975 to 1985, the hospital serving the mesothermal
valleys of Comarapa treated 47 pesticide poisonings; of these 15%
died and, of the total, 45% were children (INSO 1987).
Other studies clearly demonstrate the extent of this problem in Bolivia (Condarco
and Medina 1986a,b; INSO 1986; Malgarejo 1987). In the mesothermal
valleys where tomatoes are cultivated, 25% of people examined had reduced
levels of cholinesterase activity, 16% of them were under 18 years of age. Most
(94%) agricultural workers had no knowledge about the safe use of pesticides.
Our concern was to determine the real incidence of pesticide poisoning in the
three ecological areas and what factors affect this problem, and to find suitable
alternatives for pest control in the Bolivian environment. Specifically, this
study examined the extent of use of organophosphates and their effect on the
health of the agricultural worker and on the ecology The results of this project
will provide a basis for future studies in this field, through the health-care
network of the Ministry of Health.
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