Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/1/1996
Publication Date: N/A
Technical Abstract: Alluvial aquifers and other unconsolidated aquifers have been shown to be the most susceptible to agrichemical contamination in the Midwest. A preliminary study indicates that the Skunk River alluvial aquifer is receiving herbicides from leakage through the bed of a tributary stream, Walnut Creek. Measurements made in April and June, 1994, showed the stage in the creek to be higher than in both the creek bed and the alluvial aquifer, 4 meters beneath the creek. Atrazine concentrations in water from the stream bed were similar to those in the creek during April and June. Concentrations in the creek and creek bed during June were one order of magnitude larger than in April. Atrazine concentrations in the aquifer doubled from April to June. Atrazine flux rates through the stream bed were estimated to be 2 to 3 orders of magnitude greater than estimates of flux through field leaching. If this process of stream-bed leaching occurs in many hydrologic settings, it may be necessary to reexamine the utility of using field-leaching models to explain groundwater contamination by agricultural chemicals.