The U.S. Environmental Protection Agency (EPA) recently released a report entitled, "Literature Review of Contaminants of Livestock and Poultry Manure and Implications for Water Quality". This report summarizes research results surrounding manure use and includes information on antibiotics and hormones, among other topics. No policy recommendations are made in the report.
The report notes that livestock and poultry manure can contain a variety of pathogens, many of which are not a health risk for humans. However, other pathogens can cause infection in both humans and animals and are therefore termed, “zoonotic.” Common zoonotic pathogens in manure include Escherichia coli 0157:H7, Campylobacter, Salmonella, Cryptosporidium parvum and Giardia lamblia. Viruses can also be associated with manure, though less is known about their survival in manure. Survival of microorganisms in manure, soils, and water varies greatly, from days to as a year in some cases, depending upon the organism and the environmental conditions.
Risks from manure-associated pathogens can arise when manure runoff, spills or infiltration enable microorganisms to reach surface water or groundwater, or when land-applied manure, or irrigation water impacted by manure, comes into contact with food crops. The level of risk to humans depends upon a number of factors that dictate how readily the microorganisms are transported through the environment and how long they remain infectious.
The report points out that most outbreaks of waterborne and foodborne gastrointestinal illness, even those caused by zoonotic pathogens, are attributable to human fecal contamination, although agricultural sources have been implicated.
Good manure management practices can help minimize many problems related to other contaminants that may be found in manure. The U.S. Department of Agriculture (USDA) and their state partners provide technical and financial assistance, as well as conservation practice standards for nutrient and manure management. The report provides an introduction to existing programs and links to find additional information.
Download the report in PDF form at http://water.epa.gov/scitech/cec/upload/Literature-Review-of-Contaminants-in-Livestock-and-Poultry-Manure-and-Implications-for-Water-Quality.pdf.
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