Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 9/1/2010
Publication Date: 8/8/2011
Citation: Schroder, J.L., Zhang, H., Richards, J.R., He, Z. 2011. Sources and contents of heavy metals and other trace elements in animal manure. In: He, Z., editor. Environmental Chemistry of Animal Manure. New York, NY: Nova Science Publishers. p. 385-414. Interpretive Summary:
Technical Abstract: Trace elements take part in various physiological functions including enzyme formation, vitamin formation, metabolism, and electron transport in animals. Thus, trace elements are added to livestock and poultry diets to prevent diseases, improve weight gains and feed conversion, and increase egg production for poultry. Unfortunately, many times the addition of trace elements to livestock and poultry diets exceeds dietary requirements. Recently, the application of animal manures has been identified as a major source of trace elements in soil. Animal manures are enriched with potentially toxic trace elements such as As, Cu, and Zn and land application of manures should consider the loadings of these trace elements in soil. Several approaches have been suggested to reduce environmental problems due to manure application including reduction of the water soluble fraction of trace elements in manures and reduction of trace elements in animal feed. Chemical amendments have been successfully used to reduce the water solubility of trace elements, and organic forms of trace elements (i.e. chelates and complexes) have been used to increase availability in feeds. However, perhaps the most significant way to reduce trace elements in manures is by reducing trace element supplements in livestock and poultry diets. Unfortunately, at the present time, concerns exist as to the effects of these reductions on livestock and poultry health, so additional research is needed to evaluate these effects.