| Abstract | Society's complex relationship with geology is best examined through our dependence on metals. Indeed, humans have been using metals for over 8000 years. Many of the original commodities exploited
(i.e., Ag, Au, Cu, Fe, Hg, Pb and Sn) were used in making jewellery, weapons, cosmetics, and in rituals, and were often symbols of wealth. These metals were first discovered and used in their native state (except Pb from galena and Sn from
cassiterite); smelting followed around 4500 years ago as a means to acquire metals and create alloys such as bronze. The potential toxicity of some of these metals was recognized in ancient times; for example, Roman slaves regularly died when exposed
to Hg vapours in the Spanish mines (ca., 2400 years B.P.). Despite this knowledge, Hg was used medicinally up to the 1950s and even today Hg is still widely used in dental amalgam, in developing countries to extract Au and in certain cults in their
talismans. In contrast, metals such as Cu, Fe, I, Se and Zn are considered essential trace elements.
Although we understand how metals and metalloids behave in the environment and how they can impact human and environmental health (e.g.,
toxicity related to Pb and neurological behaviour, F and skeletal fluorosis, As and cancer; and deficiencies related to I and goitre, Se and Keshan Syndrome, and so on), a myriad of issues need to be addressed including: understanding exposure
pathways and confounding factors (e.g., smoking); determining bioaccessibility and bioavailability; and examining how geological materials become either a hazard or a health benefit. Geoscientists working with health professionals can assist in
epidemiological studies. Educating decision makers and the general public on the hazards of metals and metalloids will aid in mitigation and promote a healthy environment. Geology and health is an emerging field, and in this International Year of
Planet Earth (IYPE) finding manageable solutions to the legacy of metals in the environment is critical. This talk examines the many faces of metals, including both their nutritional role and their potentially detrimental effects on human and
environmental health. |