Chemistry of Life 37FOCUS ON OUr ENvIrONMENTfood production and a Chemical arms race
if you eat like most people in developed countries, a
variety of agricultural chemicals help provide your daily
supply of organic compounds. for example, the lettuce for
your salad most likely grew in fertilized cropland, and the
grower may well have used herbicides to eradicate weeds,
insecticides to kill unwanted insects, and fungicides against
harmful molds and other destructive fungi.
pesticides are quite useful in some applications. many
research studies show that modern pesticides used properly
increase food supplies and profits for farmers. they also save
lives by killing disease-causing insects and other pathogens.
and despite understandable worries of consumers, for now
there is little evidence that the usual amounts of pesticides
in or on food pose a significant health risk.
on the other hand, pesticides are powerful chemicals.
some kill natural enemies of the targeted pest, and others
harm wildlife such as birds. some, such as DDt, stay active
for many years. (DDt is banned in the United states,
although not in many other countries.) and when people
are exposed to unsafe doses, either by accident or misuse,
some pesticides can trigger rashes, hives, headaches,
asthma, and joint pain. according to some authorities,
young children who are exposed to pesticides applied to
keep a lawn thick and green may be at risk of developing
learning disabilities and other problems. manufacturers
dispute these claims, but it is worth noting that according
to the U.s. environmental protection agency, homeowners
in the United states use ten times more pesticides on their
lawns than farmers do in agriculture.
in section 2.10 we discussed how scientific studies of
trans fats led to stricter regulations on their use. in the
Figure 2.31 Vegetables and fruits may contain residues of agricultural chemicals. The photograph at right shows a low-flying
crop duster raining pesticides in an agricultural field. Atrazine is applied this way to cotton and some other crops.
Inga Spencer/Tom Stack & Associatesfuture we can expect to see expanded research on the
health effects of several chemical compounds that find their
way into the drinking water supplies of millions of people
around the globe.
one of these compounds is the weed killer atrazine. in
2009 the U.s. environmental protection agency announced
new efforts to study possible health impacts of atrazine,
which has been used widely in agriculture and lawn care
products for more than forty years (figure 2.31). as a result
of this long-term use, water supplies in many parts of the
United states contain atrazine, although at levels that were
thought to be safe for human consumption.
recently, though, new research has suggested that
atrazine may be associated with reproductive problems in
humans. the issues include premature births, newborns
with abnormally low birth weights, and menstrual problems
in women. some studies suggest that atrazine may be
implicated in some cases of prostate cancer. the jury is
still out on all these questions, and the manufacturers of
atrazine maintain that their product is safe when applied
properly. the hope is that new research will clarify whether
current levels of atrazine in drinking water are safe, or if
more stringent regulations on its use are in order.© iStockphoto.com/cislander2.14
Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).