Geological and Anthropogenic Factors Influencing Mercury Speciation in Mine Wastes

Mercury (Hg) is a naturally occurring element that poses considerable health risks to humans, primarily through the consumption of fish which have accumulated harmful levels of mercury in their tissue. This bioaccumulation of mercury in fish is a result of elevated exposure from a number of sources including industrial emissions, atmospheric deposition, and mercury-bearing products such as thermometers, batteries, electrical switches, and fluorescent light bulbs. In California, however, a significant amount of mercury enters the environment through the dozens of mercury mines located throughout the California Coastal Range (Figure 2), where thousands of tons of mercury were recovered for use in gold recovery further east in the Sierra Nevada. The transport of mercury from these remote poorly-monitored mine sites has resulted in elevated mercury levels in more populated urban regions such as the San Francisco Bay Area. Understanding the movement and geochemistry of mercury from mines in California is therefore necessary in order to predict the potential impacts and hazards associated with this form of mercury contamination.