The Earth, Source of Health and Hazards: An Introduction to Medical Geology

Insidious hazards that affect humans and other living creatures are addressed in this review. Debilitation and disease that may arise from naturally occurring gases, minerals, and elements create problems with characteristics that inhibit progress toward adequate and immediate solutions: (a) Human or animal reactions are delayed, not detected until long after the original exposure; (b) sporadic or continual low-level exposures to the minor or trace amounts of offending materials via the atmosphere, hydrosphere, and lithosphere are difficult to evaluate; (c) the air, water, and food consumed may contain hazardous substances that go unnoticed; and (d) health reactions depend on bioavailability of the hazard and susceptibility of the individual. The etiology of many chronic diseases from exposure to earth materials—asbestos disease, As- and Se-induced cancers, and other disabilities—are suspected, but precise mechanisms of induction are presently unknown. Stipulation of disease from Earth-based hazardous materials requires collaboration of Earth and biomedical scientists to avert, or at least ameliorate, future disease and debilitation.