Changes

Another pathway through which humans come in contact with the earth’s elements is by water intake whether from man-made wells, rivers, streams or lakes.<ref name=Skinner /> These emanate from groundwater which might have leached both toxic and non-toxic elements from rocks through which it flowed.

Another pathway through which humans come in contact with the earth’s elements is by water intake whether from man-made wells, rivers, streams or lakes.<ref name=Skinner /> These emanate from groundwater which might have leached both toxic and non-toxic elements from rocks through which it flowed.

Inhalation of volcanic gases and dust from deserts, un-tarred roads, mines and volcanic emanations form another important pathway of exposure to dangerous elements. Volcanism is the principal process that brings elements to the surface from deep within the earth. The volcanic eruption of Mount Pinatubo is a splendid example of the dramatic effects of geology. During just two days in June 1991, Mount Pinatubo, Philippines, ejected 10 billion metric tonnes of magma and 20 million tonnes of SO2 for over 15,000 meters high into the atmosphere; the resulting aerosols influenced global climate for three years. This single event introduced an estimated 800,000 tonnes of zinc, 600,000 tonnes of copper, 550,000 tonnes of chromium, 100,000 tonnes of lead, 1000 tonnes of cadmium, 10,000 tonnes of arsenic, 800 tonnes of mercury, and 30,000 tonnes of nickel to the surface environment (Garrett, 2000).

Inhalation of volcanic gases and dust from deserts, un-tarred roads, mines and volcanic emanations form another important pathway of exposure to dangerous elements. Volcanism is the principal process that brings elements to the surface from deep within the earth. The volcanic eruption of Mount Pinatubo is a splendid example of the dramatic effects of geology. During just two days in June 1991, Mount Pinatubo, Philippines, ejected 10 billion metric tonnes of magma and 20 million tonnes of SO2 for over 15,000 meters high into the atmosphere; the resulting aerosols influenced global climate for three years. This single event introduced an estimated 800,000 tonnes of zinc, 600,000 tonnes of copper, 550,000 tonnes of chromium, 100,000 tonnes of lead, 1000 tonnes of cadmium, 10,000 tonnes of arsenic, 800 tonnes of mercury, and 30,000 tonnes of nickel to the surface environment.<ref>Garrett, R. G., 2000, Natural distribution and abundance of elements, ''in'' O. Selinus, ed., Essentials of medical geology: Berlin, Springer, p. 35–57</ref>

==Health issues arising from selected elements and geological materials and processes==

==Health issues arising from selected elements and geological materials and processes==