A multidisciplinary study was carried out to determine the ultimate fate of various toxic elements or pathogens associated with Florida and Chicago municipal sludges when applied to soil-plant-water systems and to determine physiologic, pathologic, growth, and reproductive responses of cattle, swine, and poultry fed sludges, grains, or forages from soils pretreated with urban liquid digested sludges as well as health effects in mice receiving liver or kidney tissues from steers and swine exposed to such feeds or contaminants. Minimal differences occurred in growth performance or egg production in cattle, swine, or poultry fed forage or grain from soils pretreated with a variety of urban sewage sludges. Cattle and swine tissues, when fed to mice, resulted in alterations of the normal mineral balance as well as reproductive performance. Tissues from animals intended for human consumption exposed to sarcocyst contaminated sewage sludges may serve as health hazards for animals and humans. Application of urban sewage sludges at 19.8 t/hectare produced equivalent plant growth stimulation for corn, barley, wheat, and sorghum as commercial fertilizers. Certain bacteria, commonly associated with sludges, disappear in a few days after soil or plant application; however certain viruses and parasites were shown to persist.