Geochemistry of the Tropical Environment -- Bioavailability of Trace Elements and Risk Assessment -- Medical Geology of Fluoride -- Iodine Geochemistry and Health -- Nitrates in the Geochemical Environment -- Medical Geology of Arsenic -- Water Hardness in Relation to Cardiovascular Diseases and Urinary Stones -- Selenium- A New Entrant to Medical Geology -- Geological Basis of Podoconiosis, Geophagy and other Diseases -- High Natural Radioactivity in Some Tropical Lands - Boon or Bane? -- Baseline Geochemical Data for Medical Geology in Tropical Environments. Over two billion people live in tropical lands. Most of them live in intimate contact with the immediate geological environment, obtaining their food and water directly from it. The unique geochemistry of these tropical environments have a marked influence on their health, giving rise to diseases that affect millions of people. The origin of these diseases is geologic as exemplified by dental and skeletal fluorosis, iodine deficiency disorders, trace element imbalances to name a few. This book, one of the first of its kind, serves as an excellent introduction to the emerging discipline of Medical Geology.