Effect of Animal Feeding Operations on Water Quality

Project Chief: Brian Bergamaschi

California is the nation's number one producer of dairy products. Its 1.4 million dairy cows produced 3.2 billion gallons of milk in 1998, generating 18 percent of the national supply and over $3.6 billion in sales. However, these cows generate approximately 30 million tons of manure each year, so proper management of dairy waste on California's 2,700 dairy farms is one of the state's most pressing environmental issues.

Animal feeding operations (AFOs) are agricultural facilities that house and feed a large number of animals in a confined area for 45 days or more during any 12-month period. Waste products from AFOs potentially threaten drinking water quality and human health by contributing contaminants such as nutrients, pathogens and pharmaceuticals. Pathogens such as E. coli, Cryptosporidium parvum, and Giardia lamblia often are associated with AFO waste and are linked to human health problems. Pharmaceutically Active Compounds (PhACs), which are routinely given to livestock, and their degradation products, are water contaminants, which may contribute to birth defects and promote the development of antibiotic-resistant strains of bacteria. Solid and liquid waste in holding ponds or lagoons is subsequently used for irrigating nearby fields. The fate of these contaminants is uncertain. Rainfall can create manure-laden runoff that transports these contaminants to surface waters and may infiltrate into aquifers used as drinking water resources.

The objective of this project is to gain a better understanding of the presence and transport of pathogens and pharmaceuticals in ground water in animal feeding operations. This understanding and knowledge provides a scientific basis for management of drinking water quality in the California Central Valley. This project develops a planning model useful for managing drinking water constituents of concern. The focus is on sites where contaminants were found. The data from these samplings and the column study are utilized in a mathematical flow and transport model, which provides a tool to assess the best mitigation strategies for manure management.

Contact Information

Brian Bergamaschi
Office phone: 916-278-3000

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