THE WATERWHEEL: A series dedicated to one of our most treasured resources - Water
THE WATERWHEEL - Sources of Man-Made Chemicals in Drinking Water
by Don Janssen, UNL Extension Educator
Scattered throughout Nebraska are areas that have both sandy soils and shallow water tables. The high permeability of these soils, combined with the relatively short distance to the water table, make these areas particularly sensitive to contamination. Excessive rainfall or over-irrigation can cause downward movement of water through the soil profile. Those man-made chemicals which do not bind strongly to soil particles can be carried with the downward moving water and eventually can be leached to the groundwater. Leaching and groundwater contamination takes place in areas without sandy soils or a high water table, only at a slower rate.
Activities near a well, particularly mixing or storing chemicals, potentially can contaminate the water supply. In some areas, depending on the relative location of the well and sites where various man-made chemicals are used, contamination could occur from normal application and use. Used motor oil dumped on the ground, spilled fuel near storage tanks, pesticides spilled during mixing and loading and improperly dumped household products are all examples of man-made chemicals that could leach into groundwater. In addition, leaking underground fuel tanks can contaminate groundwater without visible evidence on the surface.
Man-made chemicals can enter groundwater through more direct routes. Improperly constructed wells or older wells with leaks around or through the casing can allow contaminants to seep into groundwater. Abandoned wells that are not properly sealed also provide direct pathways to the aquifer. Pesticide applications near such wells or any chemical spills on the surface could potentially contaminate groundwater if surface runoff moves toward the well.
Prevention of spills and immediate cleanup of any spills are among the best ways to prevent contamination of groundwater with man-made chemicals. Proper site selection and construction of domestic water wells can reduce potential contamination of drinking water. Wells no longer needed should be properly decommissioned to eliminate direct conduits to the aquifer.
This article appeared in the NEBLINE Newsletter.
PHOTO Credit: Rita Shelley
University of Nebraska-Lincoln in Lancaster County
Web site: lancaster.unl.edu
444 Cherrycreek Road, Suite A, Lincoln, NE 68528 | 402-441-7180
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