|March 19, 2004:
Criteria for sustainability of agricultural systems usually
are things like erosion, runoff, and yield stability.
Citing these, some “experts” think that current
conventional agriculture is relatively sustainable. In
fact, a professor of agriculture at UC Davis told me that
just the other day.
The Achilles heel of the “conventional agriculture
is sustainable” argument may be farm worker health
(I would say it is just one of several Achilles heels,
aquatic pollution is another huge one). If the levels
of pesticides going into the foods we eat are too low
to cause immediate measurable health problems, the experts
will say that the food system is safe. And this is what
they do, even though they do not know the long-term
consequences of low-level exposure.
Farm workers, however, are showing up with immediate
and rather alarming health problems, associated with
A team of researchers from the National Institute of
Environmental Health Sciences did neurobehavioral tests
on a large group of farm workers (288), mostly Latino,
in Florida and compared them with an identical group
from the same community who had never done farm work.
They found a significant degradation of performance
on neurobehavioral tests in farm workers compared to
the control group, and the more years of farm work they
did, the more degraded was their performance.
The farm workers had worked in three types of agriculture:
ornamental fern production, nurseries, and citrus harvest.
The subjects were carefully screened for traits that
could skew the results -- for instance farm workers
who had experienced acute pesticide poisoning were rejected,
since the objective was to determine the effects of
The battery of neurobehavioral tests were all well
established tests designed to evaluate a range of neurological
health criteria. They have technical names like digit
span, symbol digit latency, vibrotactile threshold,
visual contrast sensitivity, tapping, Santa Ana pegboard
test, grip strength, and postural sway.
Fern work was particularly strongly related to lessened
neurobehavioral performance. Fern production is pesticide
intensive and the workers handle the ferns intensively.
Poor neurobehavioral performance correlated with the
number of years of farm work in both current and former
Some tests showed no effect from farm work. The tests
that were affected by farm work were digit span, tapping,
Santa Ana pegboard test, and postural sway.
The fact that the researchers excluded subjects who
had experienced acute pesticide poisoning in the past
is important, as agrichemical industry scientists have
in the past attacked studies that included acute poisoning
subjects, saying that the acute poisonings cause the
neurobehavioral problems and that chronic exposure is
Don Lotter has a Ph.D. in agroecology and has worked
in sustainable agricultural development in North America,
Latin America, and Africa over the past 25 years. He
can be contacted via his website www.donlotter.com