Comparative toxicity of feeding dried urban sludge and an equivalent amount of cadmium to swine.

Three rations, an 18.71% protein swine starter diet (control), a basal diet containing 83 micrograms of Cd/g of diet, or a basal diet containing 50% Chicago sewage sludge (CSS) providing 83 micrograms Cd/g of diet, were given to weanling pigs for 9 weeks. Depressed growth occurred in both groups given Cd-treated diets in comparison with growth in pigs fed the control ration. Microcytic, hypochromic anemia occurred in the group given the Cd-supplemented diet, but there were no significant differences in the hematologic values between pigs in the control and CSS-supplemented diets. Toxicosis probably resulted from combining CSS as 50% of the diet due to a deficiency of available protein or other essential nutrients or from the accumulation of hazardous chemical residues including Cd, Cu, Cr, Hg, Ni, or Zn. An increased amount of Fe in the CSS-treated ration apparently protected the pigs against the microcytic, hypochromic anemia.