They now are looking at more effective herbicides and cultural practices, as well as ways to apply them with underwater injector lines. Currently used power boats are expensive, raising the cost to several hundred thousand dollars for large control efforts. Inexpensive vegetable cooking oils might be used to clean groundwater contaminated with nitrogen fertilizer. When not used with care, the fertilizer can move downward through soil. ARS scientists have found that oils squeezed from corn or soybeans provide a carbon source that increases the numbers of helpful microorganisms.
Scientists envision injecting oil under pressure into the base of existing wells.
It would become trapped in soil particles and form a filter. When water is pumped, it would pass through this natural filter, becoming cleansed. Or, above-ground troughs filled with sand and gravel might be used to treat pumped groundwater. This would eliminate a potential health threat to humans and animals. The researchers have decontaminated water containing 200 times the maximum permissible nitrate level for U.S. drinking water.