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Problems encountered with the locally designed protective clothing included
a sensation of warmth and the plastic material at the sides of the vests and the
bags covering the hands was easily torn.
There was no statistically significant difference in cholinesterase levels in red
blood cells before and after exposure to methyl parathion among farmers with
and without protective clothing. Mean urinary p-nitrophenol levels were not
significantly different between exposure groups after spraying.
In the two methyl parathion studies, no variability in meteorological parameters
and no clinical symptoms of organophosphate poisoning were observed
in any of the participants.
Study three, using monocrotophos, indicated that hands were exposed during
mixing and loading operations, particularly those of farmers not using protective
measures. High exposure of uncovered hands and face to spray mists
was observed during spraying activities. However, no acute adverse health
effects were observed during application of monocrotophos. Cholinesterase
activity in whole blood or red blood cells was not significantly affected, but in
all subjects plasma cholinesterase level decreased by 40%.
Urinalysis for dimethyl phosphate confirmed absorption in all subjects,
regardless of the use of protective measures. In this study, protective measures
were mainly used during mixing and loading activities. However, because
mixingloading and spraying activities were carried out by the same person,
no definite conclusions can be drawn regarding the effects of the protective
measures.
Conclusions
These studies demonstrated that, in the course of a normal spraying operations,
Filipino farmers are exposed to contamination of their clothing and
potential dermal absorption by organophosphate pesticides. However, no
adverse health effects were noted.
The area of the body with highest potential for dermal exposure and penetration
is the hands. Mixing and loading activities had the highest potential for
dermal contamination; undertaking all the activities was associated with the
highest potential for dermal penetration.
The protective clothing studies had different results. In the methyl parathion
study, pesticide-residue levels in the group who used protective clothing were
lower than those who were not protected. In the monocrotophos study, no
conclusion could be drawn. For both pesticides, there was no change in
cholinesterase levels in red blood cells after exposure.
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