The study attacks one of the problems inherent in disposing of refuse on land: the ever-present danger that-unless properly engineered in a sanitary landfill--the wastes will adversely effect ground-water resources. Hydrogeologic and water quality studies of five landfills in northeastern Illinois were carried out. The distribution and concentration of dissolved solids in the vicinity of four of these landfills was found to be controlled by the configuration of the ground-water flow system. The major factors influencing the attenuation of the dissolved solids appear to be the particle size of the earth materials through which they move and the distance that they move.