Environmental Engineering Reference
In-Depth Information
Pests
are defined as living organisms occurring where they are not wanted or caus-
ing damage to crops or humans or other animals (USEPA 2009f). Examples include the
following:
• Insects
• Mice or other animals
• Unwanted plants (weeds)
• Fungi
• Microorganisms, such as bacteria and viruses
Perhaps the most famous of all pesticides is the now banned substance called dichlorodi-
phenyltrichloroethane (DDT). It became famous as an environmental contaminant after
the topic
Silent Spring
written by Rachel Carson was published in 1962 (Carson 1962). The
topic catalogued the environmental impacts of the indiscriminant spraying of DDT in
the United States and questioned the logic of releasing large amounts of chemicals into
the environment without fully understanding their effects on ecology or human health.
DDT (CAS registry number 50-29-3) is now considered a probable carcinogen (Group:
A2) by USEPA (2009b) and is no longer used as a pesticide in the United States after its
use
was banned in 1972 (Note: DDT
production
was not stopped. The 2001 United Nations
Environmental Program meeting held in Stockholm, Sweden (and put into effect in 2004)
permitted its use for “vector control”—organisms that produce pathogens, such as mos-
quitoes). The structure of DDT is shown in Figure 7.17.
Common pesticides and herbicides, including DDT, are listed
in Table 7.14 along with the respective CAS registry numbers
and carcinogenicity ratings.
USEPA banned the use of the pesticide
chlordane
in 1983
because of potential environmental and human health concerns
for all applications except termite control (ATSDR 1995b).
Malathion
is an organophosphate insecticide widely used in
agriculture, residential landscaping, and public recreation areas.
Malathion is used widely to control mosquitoes, the West Nile
Cl
Cl
Cl
Cl
Cl
FIGURE 7.17
Basic molecular structure of
DDT.
TABLE 7.14
Common Pesticides and Herbicides
Pesticide
CAS Registry Number
Carcinogenicity Rating
Chemical Formula
DDT
50-29-3
Group: A2
C
14
H
9
Cl
5
Chlordane
57-74-9
Group: A2
C
10
H
6
Cl
8
Malathion
121-75-5
Group: A4
C
10
H
19
O
6
PS
2
Permethrin
52645-53-1
Group: A2
C
21
H
20
Cl
2
O
3
Toxaphene
8001-35-2
Group: A2
C
10
H
10
Cl
8
a
Herbicide
Glyphosate 1071-83-6 Group: A4 C
3
H
8
NO
5
P
2,4-D 94-75-7 Group: A4 C
8
H
6
Cl
2
O
3
Pentachlorophenol 87-86-5 Group: A2 C
6
H
4
Cl
5
O
a
Represents a mean chemical formula since toxaphene is composed of a mixture of
compounds.
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