Geochemical Conditions Which Initiate the Natural and Anthropogenic Release of Metals and Selected Mitigation Measures

Metals such as arsenic, chromium, copper, nickel, zinc and lead occur naturally in the environment, and naturally occurring changes or anthropocentric activities such as mining or development can create geochemical conditions which will initiate the release of toxic metals into surface or groundwater. The talk will focus on the natural conditions that allow the leaching of metals from selected pyrite-rich mountain rocks in the Andes of Peru which create acid rock drainage related to climate change and glacial melting. A comparison of geochemical conditions will be made with a water recycling project involving wastewater reinjection in a south Florida aquifer and the initial unintended consequences of geochemical changes in the subsurface. Mitigation measures to address the natural and anthropogenic release of metals will be discussed.