Agriculture Reference
In-Depth Information
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repellant on their skin, weed spray at the park, bug killer sprayed in their
school . . . not to mention the stew of insecticides, herbicides, fungicides,
and fumigants that have left residues on their food. The bottom line is that
we do not know the long-term combined effects of these multiple, constant
chemical exposures, but we do know that many individual agrichemicals
are dangerous and cause health problems.
Pe sticides and Health
There are two ways to think of pesticide illness: acute and chronic. Acute
exposures occur within a few hours or a day. Acute toxicity is commonly
defined as the concentration required to kill 50 percent of laboratory test
animals through either skin contact or ingestion (Trautmann et al. 1998).
Acute poisonings lead to obvious, sudden illness that can range from al-
lergic reactions to severe sickness or death. For each of the main types
of agrichemicals, there are various reactions to acute poisoning (Moore
2002; Reigart and Roberts 1999). Nerve poison pesticides are organophos-
phates and methyl carbamates that are widely used around the world; acute
exposures to these cause headache, dizziness, or even convulsions, coma,
and death. Organochlorine pesticides are still used throughout the world,
although several older compounds (such as DDT) have been banned; these
pesticides cause allergic reactions, nausea, and convulsions. Pyrethrins are
widely used in agriculture and home gardens; acute exposures can cause
nausea, dizziness, headache, vomiting, and diarrhea. Dipyridyl pesticides
like paraquat are commonly used worldwide and cause many acute poison-
ings each year. Symptoms include organ failure, lung damage, and pain; they
can even cause death. Chlorophenoxy herbicides include common weed-
killers such as 2,4-D and the base ingredient inAgent Orange; they cause skin
irritation, headache, nausea, fever, irregular heartbeat, andmental confusion
when acute poisoning occurs.
Chronic health effects of pesticide use may not be seen in humans until
years or decades after exposure (Reigart and Roberts 1999); that is why
it is so difficult to pinpoint the causes of illnesses related to agrichem-
icals. The organochlorine insecticides and chlorophenoxy herbicides are
the main groups of chemicals associated with long-term health problems,
such as cancer, neurological problems, developmental delays, reproductive
disorders, and hormonal (endocrine) disruption (Moore 2002). Certainly,
it is difficult to identify a precise pesticide exposure that may have occurred
twenty or thirty years ago and prove that it caused the cancer present in
someone today. But this complexity is also “convenient.” The agrichemical
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