Gold , mercury contamination from mining processe

In Nome, Alaska, gold mining is responsible, in part, for the elevated mercury levels (max. 0.45 mg/kg DW) measured in modern beach sediments. However, higher concentrations (max. 0.6 mg/kg) routinely occur in buried Pleistocene sediments immediately offshore and in modem nearby unpolluted beach sediments (1.3 mg Hg/kg). This suggests that the effects of mercury contamination from mining are less than natural concentration processes in the Seward Peninsula region of Alaska. 

The most mercury-contaminated site in North America is the Lahontan Reservoir and environs in Nevada. Millions of kilograms of liquid mercury used to process gold and silver ore mined from Virginia City, Nevada, and vicinity between 1859 and 1890, along with waste rock, were released into the Carson River watershed. The inorganic elemental mercury was readily methylated to water-soluble methylmercury. Over time, much of this mercury was transported downstream into the lower reaches of the Carson River, especially... 

---