Arsenic is a naturally occurring element in rocks, soils, and the waters in contact with them. It is found in ground water as the result of minerals dissolving from weathered rocks and soils. This site links to data, maps, and more.
Explains the natural and human-affected factors that determine the concentration of contaminants in groundwater, especially where the concentration is different at the surface than at depth, and where pumping varies with time.
Uranium, arsenic, and nitrate were the inorganic constituents that were most frequently detected at high concentrations, mostly in shallower wells. High and moderate concentrations of arsenic were detected in deeper wells.
Trace elements were present at high concentrations in 32% of the primary aquifers here, and at moderate concentrations in 17%. Of particular interest are aluminum, arsenic, vanadium, boron, fluoride, chromium, lead, and molybdenum.
Five trace elements with human-health concerns were detected at high concentrations: arsenic, boron, molybdenum, strontium, and vanadium. Chromium and fluoride were detected at moderate concentrations.
Arsenic and boron were the trace elements that most frequently occurred at high concentrations. Fumigants (pesticides) were detected at high concentrations in 3% of the primary aquifers. Herbicides and insecticides were detected at low concentrations.
Iron ore containing elevated concentrations of trace metals was smelted here during 113 years of operation (1771-1883). We sampled a variety of materials nearby to determine the amount of metals such as arsenic, chromium, copper, lead, and zinc.