Over the past year, a number of private wells in southeast Hernando County have been identified as having elevated levels of arsenic.
The area of contamination is not clearly defined, but is generally bordered by State Road 50 on the north, Interstate 75 on the east, the Hernando/Pasco county line on the south, and U.S. 41 on the west.
The Hernando County Health Department, in conjunction with the Florida Department of Environmental Protection, has tested about 400 wells in this area and found approximately 150 to be contaminated with arsenic above a safe level.
The federal Environmental Protection Agency standard for maximum contaminant level is 10 parts per billion. Test results indicate arsenic levels in these locations range from below 1 ppb to 236 ppb.
Health risks at these levels would result from long-term (70 years') exposure; therefore, concern about immediate risk to residents is minimal.
Arsenic is a naturally occurring element widely distributed in the earth's crust. In addition to groundwater and soil, arsenic is found in pesticides and in products used to preserve wood. Once exposure to the source of the arsenic is discontinued, levels in the body will often decrease in a matter of days.
Arsenic in drinking water can come from several different sources.
In rural areas, these sources may include former agricultural land treated with arsenic-based pesticides, former cattle dip vats and naturally occurring arsenic.
When testing through the Florida Department of Health reveals levels above 10 ppb, the well owner is provided with a temporary supply of bottled water and given the opportunity to have a filter installed to remove the arsenic.
Bottled water, filters and maintenance of filters is provided by the DEP free of charge to the homeowner. Private drinking water well testing is provided free of charge by the Hernando County Health Department.
There does not appear to be a discernible geographic or depth distribution in the contaminated wells. The Department of Health will continue to sample and assist the public to address public health issues and concerns.
Albert Gray is the environmental health director for the Hernando County Health Department.