Sources and Contents of Heavey Metals and Other Trace Elements in Animal Manure.

Trace elements are natural and added components of livestock and poultry feeds. Appropriate amounts of these trace elements in the diet of livestock and poultry ensures both health and reproduction. Unfortunately, many times trace metals that are added to livestock diets by producers or feed companies exceed dietary requirements. Because most of the trace elements ingested by livestock and poultry are excreted via the feces and urine, the concentration of metals in manures is dependent on the concentrations of these metals in the animal’s diet. Large quantities of animal manures are generated worldwide and virtually all animal manures are land applied. The application of animal manures has been identified as a major input of trace elements to soils and repeated applications has increased concentrations of trace elements in soil. This presentation will discuss concentrations of metals in different types of animal wastes, the sources of the metals, and the impact of metal accumulation in manure applied soils. Strategies for minimizing metal build up will also be discussed.