Agriculture Reference
In-Depth Information
CHAPTER 7
F IR ST A ID A ND T HE H AR MF UL
EFFECTS OF PESTICIDES
I.
HARMFUL EFFECTS OF PESTICIDES
Most pesticides are designed to harm or kill pests. Because some pests
have systems similar to the human system, some pesticides also can harm or
kill humans. Fortunately, humans usually can avoid harmful effects by avoid-
ing exposure to pesticides.
Humans may be harmed by pesticides in two ways; they may be poisoned
or injured. Pesticide poisoning is caused by pesticides that harm internal or-
gans or other systems inside the body. Pesticide-related injuries usually are
caused by pesticides that are external irritants.
Pesticides that are chemically similar to one another cause the same type
of harmful effects to humans. These effects may be mild or severe, depending
on the pesticide involved and the amount of exposure, but the pattern of ill-
ness or injury caused by each chemical group is usually the same. Some pes-
ticide chemical families can cause both external irritation injuries and internal
poisoning illnesses.
Some pesticides are highly toxic to humans; only a few drops in the
mouth or on the skin can cause extremely harmful effects. Other pesticides
are less toxic, but too much exposure to them will also cause harmful effects.
A good equation to remember is:
Hazard = Toxicity x Exposure
Hazard
is the risk of harmful effects from pesticides. Hazard depends on
both the
toxic ity
of the pesti cide and the
expos ure
recei ved in any situa-
tion.
A.
EXPOSURE
When a pesticide comes into contact with a surface or an organism, that
contact is called a pesticide exposure. For humans, a pesticide exposure
means getting pesticides in or on the body. The toxic effect of a pesticide
