The Washington County Lead District � Potosi Site includes soil,
groundwater, surface water and sediment contaminated with arsenic, barium,
cadmium and lead associated with historical mining practices in southeast Missouri.
The Potosi area encompasses about 47 square miles in the northeastern part of
Washington County, Missouri. Remnants of mining activities throughout the area
include strip mines, mineshafts, mine dumps, tailing areas, tailings ponds and
associated dams. There are several large tailings impoundments, associated dams
and leachate ponds with elevated levels of lead present at the site. Site
investigations and cleanup are ongoing.