ABSTRACT
The environment consists of air, water, and soil; 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 25.1 illustrates the transportation of lead to humans, via air, water, food, dusts, etc. The lead that enters humans is returned to the environment via excreta, refuse, dumps, incinerators, etc. Many other pollutants also have complex routes of environmental transport and affect humans. A number of more important pollutants are briefl y described in this chapter.
