Agriculture Reference
In-Depth Information
A person who is repeatedly exposed to two or more specific chemicals
may become ill even though any one of the chemicals alone would have had
no harmful health impact. Some organophosphate pesticides have been
shown to have this effect when they are used in combination.
In som e cas es, a
sin gle exp osure
to a pes ticide (or com binat ion of
pesticides) could adversely affect the exposed person's health after a period of
time. For example, large exposures to paraquat, a herbicide, may cause severe
or fatal lung injury that does not appear for 3 to 14 days after the initial expo-
sure. After an exposure, paraquat slowly builds up in the lungs and destroys
lung cells.
Some kinds of harmful effects may not occur unless a certain set of cir-
cumstances is present. These effects can occur after the first exposure, but the
likelihood is small. Continuous or frequent exposures over a long period of
time make it more likely that all the necessary factors will be present. Some
genetic changes that result in the development of cancer or other delayed ef-
fects are in this category.
Types of delayed effects include:
•
chronic effects
•
developmental and reproductive effects
•
systemic effects.
a.
Chronic Effects
Chronic effects are illnesses or injuries that appear a long time, usually
several years, after exposure to a pesticide. Some delayed effects that are sus-
pected to result from pesticides' chronic toxicity include:
•
production of tumors (oncogenic effect)
•
production of malignancy or cancer (carcinogenic effect)
•
changes in the genes or chromosomes (mutagenic effect).
Typical precautionary statements on pesticide labeling include:
•
Cancer Hazard Warning Statement: This product contains an ingredi-
ent which has been determined to cause tumors in laboratory animals.
•
NOTE: This product has been shown to cause cancer in laboratory
animals.
•
The use of this product may be hazardous to your health. This prod-
uct contains an ingredient which has been determined to cause tumors
in laboratory animals.
