The Common Mechanism of ToxicityThe common mechanism of toxicity describes how two or more pesticides produce
the same adverse health effect. The FQPA requires the EPA to evaluate pesticide tol-
erances through a combined risk assessment for all pesticides that exhibit a common
mechanism of toxicity (CMT). For example, malathion and diazinon are both or-
ganophosphate pesticides. If the EPA determines that malathion and diazinon have a
common mechanism of toxicity, then any crops that use both pesticides will have to
combine the risks of the two pesticides when setting tolerances. Historically, each pes-
ticide would have been evaluated separately.^64Endocrine DisruptersThe endocrine system is a collection of glands that are located in several areas of
the body. These glands release hormones into the bloodstream. The hormones travel
to different locations in the body and act on specific ‘‘target’’ organs. If the endocrine
system is disrupted, those organs will not receive the correct amount of hormones
and might not function properly. Many think certain pesticides at low levels in the
environment disrupt the endocrine system. The FQPA requires the EPA to develop a
test to screen pesticides for potential endocrine disruption.^65Other Areas of InquiryIn addition to topics already mentioned, this book will address a number of other
issues involving pesticides, including the following inquiries: How will the risk of pes-
ticide exposure for all Americans, but especially for children, be managed? What are
the scientific and policy issues surrounding pesticide use and farmworker safety? How
will the strategies embodied in Integrated Pest Management (IPM) reduce the health
risks associated with pesticides? What accounts for the present inadequacy of pesticide
safety measures? In what manner does pesticide toxicity and the hazards of ‘‘inert’’
ingredients exacerbate pesticide dangers? How are acute and chronic toxicity and
associated uncertainties for humans assessed? Do the legal and regulatory frameworks
under which the federal government establishes policies related to pesticide use pro-
duce effective results?Future ProspectsThe risks of acute poisoning and concerns about chronic impacts of exposure to
pesticide residues in food continue to be debated. Natural resources can be degraded
when pesticide residues in storm-water runoff enter streams or leach into ground-
water. Pesticides that drift from the site of application to wildlife habitats may harm
or kill non-target plants, birds, fish, or other wildlife. The mishandling of pesticides
in storage facilities and in mixing and loading areas contributes to soil and water
contamination.20 | Pesticides