Anthropogenic Sources

As outlined in Chap. 3, the geochemistry of environmental media is largely dependent on the chemistry of the natural sources from which they have been derived, or with which they have interacted. Thus soil and surficial sediment chemistry are strongly influenced by the composition of their parent materials. Similarly stream and river waters, derived initially from precipitation, depend on the rocks, sediments, and soils from which they come into contact and interact with for their chemical composition. However, with the evolution of humans in the relatively recent geological past there have been anthropogenic impacts on the environment, which have increased dramatically with increasing population, urbanization, and industrialization (Fyfe 1998). Thus humans have contaminated or polluted the once pristine environment, and this impact is manifested in the chemistry of environmental materials that reflect anthropogenic signals superimposed on the natural composition.