Potosi Mining Development and the Cause of Culture Collapse in Bolivia

Potosi mine in Bolivia was the largest one of silver, where mercury amalgam method was used in 16th to 18th century. The total amount of used mercury was estimated at 7500 tons, which is 12 times as much as in Minamata, Japan. First, the atmospheric diffusion of mercury at Potosi was calculated with the atmospheric dispersion model. The fall mercury distributed in the normal distribution over a radius of 100 km. From this result, 75% of the total mercury might distribute for the watershed of Rio Paraguay, 20% for the Amazonia, and 5% for the Uyuni lake. High concentration areas distributed more than 100km from Potosi. Finally, the total victims were estimated at about 24 thousand in the watersheds, which corresponds a few % of the total population in the Mojos Plane. In the pre-Inka period, many mines were dug and the heavy metals and sulfide discharged into the rivers. Probably, these mining activities might cause the culture collapse before the contact period in the same way.