What Is Present - Field Sampling: Principles and Practices in Environmental Analysis - page 235

FIGURE 9.3 Common aromatic compounds containing one and several
benzene rings bonded together. Hydrogen atoms are at the corners of
the hexagons, as shown for benzene, but are omitted in the others for
simplicity. DDT is dichlorodiphenyltrichloroethane.
benzo[α]pyrenes are examples of a type of compound sometimes called a “chicken wire”
compound. Many of these compounds, such as benzo[α]pyrene itself, are carcinogenic
and thus are of environmental concern.
A third group is compounds containing two or more benzene rings separated by
nonbenzene groups. This includes a large number of compounds that contain benzene
rings separated by a variety of substituted and unsubstituted alkyl groups. The connecting
groups thus may have other functional groups attached to them. Of particular concern are
those types of compounds containing halogens. Some of these, such as DDT, are of
general environmental concern; others are of particular human health concern. Two
chlorinated aromatic compounds of this type are given later in Figure 9.5.