Arsenic is an element that occurs naturally in rocks and soil and is used for a variety of purposes within industry and agriculture. It is also a byproduct of copper smelting, mining and coal burning. Arsenic can combine with other elements to make chemicals used to preserve wood and to kill insects on cotton and other agricultural crops. Arsenic can enter the water supply from natural deposits in the earth or from industrial and agricultural pollution. Arsenic found in groundwater within Cerro Gordo County is thought to be naturally occurring.
There is no sure way to determine a location or depth to drill a well and be certain that it will not be contaminated with arsenic. Cerro Gordo County has updated its well ordinance to require new wells to be drilled and cased through the Lime Creek Aquifer and at least 10 feet into the Cedar Valley Aquifer because the risk of a well contaminated with unsafe levels of arsenic is greatly reduced if this requirement is followed. It is also required that all new wells within Cerro Gordo County be tested for arsenic.
Arsenic in Groundwater Project Grant
The Cerro Gordo County Department of Public Health received a grant in 2010 from the Centers for Disease Control and Prevention to study why arsenic can be found in some wells within Cerro Gordo County. Approximately 60 wells within Cerro Gordo County were being tested twice per year for three years. It was shown that arsenic is naturally occurring in the bedrock in Cerro Gordo County and wells that are drilled and producing water from the Lime Creek Aquifer are at the greatest risk for arsenic contamination.
Arsenic in Groundwater Project Final Results Video