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ecause of its cationic nature, most of the compound filtered by the kidneys
is reabsorbed by the body before it can be eliminated in the urine. This high
rate of retention results in toxic effects for unusually low doses of paraquat.
The renal tubular damage caused by the compound's redox cycling properties
rapidly renders the kidney incapable of removing it from the blood, thereby
increasing the harmful effects on bodiily functions.
Paraquat is selectively toxic to the lungs, where it is found to accumulate
(Levin et al. 1979). Humans are the most susceptible species to paraquatinduced
lung damage, which is manifested as a loss of lung capacity and
function. The accompanying liver impairment adds to a general loss of vitality.
Brain damage has also been observed after paraquat intoxication.
The marked increase in the use of paraquat in Colombia (560 kL in 1980,698 kL
in 1981, 1 052 kL in 1982, and 2 483 kIL in 1987) prompted the government to
investigate its effects on the health of people working with the substance or
indirectly exposed to it in the environment. It was expected that those most
exposed would be found to suffer a pulmonary fibrosis type of pneumopathy
(a condition in which the elastic tissue of the lungs is damaged and replaced
by fibrotic, nonelastic tissue), as well as restricted pulmonary function leading
to impaired respiration. After a review of regional data on paraquat consumption,
target crops, and dosages, the municipality of Carmen de Viboral in the
district of Antioquia was selected for study.
Antioquia is an agricultural region where paraquat use is atypically high,
representing 10% of the national total. The working population of Carmen de
Viboral had allegedly been trained in the use of paraquat by local manufacturers
and the Secretariat of Agriculture of Antioquia. However, investigation
revealed that only the heads of farms had received training even though an
average of nine other people per farm were involved in plantation work using
paraquat. Information obtained from the regional health service indicated a
high prevalence of paraquat-related health problems in Antioquia, and these
figures could be extrapolated to other agricultural regions of the country with
a fair degree of accuracy.
Carmen de Viboral is located in the eastern part of Antioquia and covers an
area of 448 km2. Of its 24 657 inhabitants, 43% live in the municipality while
57% form the rural population. The entire municipal agricultural area is
devoted to potato, bean, and corn cultivation. The crop area constitutes 32%
of the township land; the rest is used for grazing or forestry. In contrast to other
areas, where itinerant workers spray the crops, the agricultural workers in
Carmen de Viboral are a stationary population.
The purpose of this study was to assess the frequency and severity of the
pathologies associated with unrestricted use of the herbicide paraquat. The
specific objectives were:
To determine the prevalence of respiratory pathologies in the population
of Carmen de Viboral;
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