Agriculture Reference
In-Depth Information
caffeine in your coffee, then there seems little to fear from the
herbicides applied to soybeans.
Measures like the LD
50
are mostly used to determine the
potential hazard to farmworkers applying the pesticides.
To determine potential risks in food consumption, the EPA
doesn't use LD
50
as a measure but something referred to as
the “No Observable Adverse Effects Level,” or NOAEL. This
is the highest dose of a pesticide that results in no negative
response in the animal, and that negative response could
be almost anything, including weight loss or changes in the
body's production of an enzyme. These studies are so com-
prehensive they sometimes observe animals over multiple
generations.
Human biology is not the same as that of lab animals, so
to be extra safe, that NOAEL threshold (again, in units like
residues per pound) is then divided by a “safety” factor—a
large number from 100 to 1,000—so that the EPA is comfort-
able deeming the pesticide as safe. This threshold takes into
account all the avenues by which residues may reach the con-
sumer, so it considers the total diet of consumers, including
food imports and even drinking water.
So pesticides are only expected to harm humans when they
are exposed to a dosage a hundred or a thousand times larger
than the dosage observed to harm animals. To understand the
importance of this safety factor, try this experiment. Consume
large portions of chocolate in one day—more than you ever
imagined eating in your life. Chances are that you will be okay.
Then feed a dog the same amount of chocolate per pound of
weight—actually, don't do that, as the dog would probably die.
This is why the EPA uses such a large safety factor. If you fed a
dog one one-hundredth as much chocolate as you ate, it would
probably be okay.
The bodies of infants and children react differently to pes-
ticides, so other factors must be considered to protect kids.
For instance, the Food Quality Protection Act states that if
reliable data on threshold effects for a child are not available,
