Because of the rapid transport of water from the ground surface in karst terrain, there is a high risk of pollution. Streams and surface runoff that enter sinkholes or caves bypass the natural filtration through the soil and provide a direct conduit for contaminants to enter the groundwater. Because groundwater in karst aquifers travels quickly, contaminants can be transmitted quickly to wells and other drinking water sources in the areas connected to that aquifer.
There are two main types of pollution that can influence karst geology water wells. There is nonpoint-source pollution and point-source pollution.
Nonpoint-source pollution comes from a widely distributed source and is not easily identified. It's also called "runoff pollution." Types of nonpoint-source pollution can include:
Animal waste from feedlots
Pesticides from lawns
Runoff from golf courses, roads, and parking lots
Soil washed from farm fields and construction sites
Trash dumped in sinkholes
Waste from failing drain fields
Because it is difficult to detect the source of nonpoint-source pollution, homeowners with wells in the limestone area should be diligent about handling and disposing of potential pollutants and periodic testing of their water supply.
Point-source pollution enters into the groundwater supply or aquifer through an easily identified distinct location through a distinct route. Most of the pollution that enters karst aquifers will be from nonpoint-source pollution; however, there are some instances where pollution may occur from point-source pollution. Potential types of point-source pollution that may occur are:
Leaking fuel storage tanks
While the source of these types of pollution is much easier to identify, citizens should still be diligent in testing their water supply of private drilled wells to ensure that there is no contamination.