ABSTRACT
The environment consists of air, water, and soil; the biota is sometimes included as one of the environmental media. Toxic substances may originate from any one medium; however, they are generally transported to other media. Humans are exposed to environmental pollutants from a variety of pathways. Figure 26.1 illustrates the transportation of lead (Pb) to humans, via air, water, food, or dust. The lead that enters humans is returned to the environment via excreta, refuse, dumps, incinerators, and so forth. Many other pollutants also have complex routes of environmental transport and affect humans. A number of more important pollutants are briefly described in this chapter.
