Antibiotic resistant bacteria constitute a significant risk to the health of animals and humans. Several studies suggest links between antibiotic resistant infections and the use of antibiotics in animal production. The European Union and other nations have banned the use of antibiotics as growth-promoters in animal feed; the prevalence of resistant bacteria has subsequently declined in farm animals, animal products, and human populations. By contrast, the US has not implemented a phase out of growth promoting antibiotics use in animal agriculture, despite some questions about its effectiveness. The proposed project seeks to explore the potential role of concentrated animal feeding operations (CAFOs) in the transport of both antibiotics and antibiotic resistance in subsurface environments. Although the number of farms that produce livestock and poultry has decreased by more than 80%, total production has increased due to CAFOs. Approximately 8.5 billion broiler chickens are produced annually (USDA, 2004). Estimating that each chicken produces 1.46{2.67 kg of waste during a 48-day lifespan [67, 84], the annual broiler production results in 12{23 billion kg of total waste. The Delmarva Peninsula is of special concern, as it contributes about 7% of the total broiler production in the US. This corresponds to about 1 billion kg of poultry waste annually. Typically, the waste is stored for some period of time and then applied to fields. It is estimated that more than 90% of the poultry litter is applied to land usually in accordance with federal and state regulations.
