ABSTRACT
Polychlorinated biphenyls (PCBs), dioxins (PCDDs), and dibenzofurans (PCDFs) all belong to a general class of pollutants labeled polyhalogenated organics. They all share the common distinction of having a benzene backbone that has chlorine substituted on it, and they all have several similarities in their modes of action, environmental pathways, and occurrence as direct products of commerce as opposed to agriculture. Bioconcentration and biomagnification are these compounds’ prominent routes of exposure. The atmosphere plays an important role in the transport and fate of these compounds. Each grouping (PCBs and PCDDs/PCDFs) will be dealt with separately under each of the following major headings: Sources and Pathways in the Environment (Sections 18.2 and 18.3), Ambient Levels (Sections 18.4 and 18.5), and Effects (Section 18.6).
