Impacts of Large Scale Production
To meet current global demand for meat, producers must operate at intensive scales. To ensure the long-term sustainability of our meat supply without jeopardizing public health and vital ecosystem services, we must address the following challenges inherent in large-scale production. For more information on any of these topics, and for works cited, please refer to our paper: A Look at Concentrated Animal Feeding Operations in North Carolina.
Intensification of meat production has increased contributions to greenhouse gas emissions. Through a process known as enteric fermentation, ruminants (which include cattle, sheep, and goats) produce methane, which has been identified as a potent greenhouse gas. Methane is then released into the ambient atmosphere through flatulence and belches. Furthermore, when animal waste decomposes, a number of gases including hydrogen sulfide, methane, and ammonia are released. The graphic at right reveals that greenhouse gas (GHG) emissions during production (i.e. growth) contribute to the majority of all GHG emissions from these animals.
Low doses of antibiotics are frequently used for growth promotion and disease prevention in animals raised in confinement, which creates an ideal environment for the evolution of resistant bacteria. These pathogens can infect humans through direct exposure to animals and their waste or through inhalation and consumption of food and water sources contaminated by animal waste.
CAFOs are classified as a "point-source" of pollution under the U.S. Clean Water Act. CAFOs and their waste management systems store massive volumes of manure in fairly small areas. This model of animal waste management poses numerous threats to nearby ground and surface water quality.
Animal waste contains a variety of nutrients, pathogens, veterinary pharmaceuticals, heavy metals, and biochemical oxygen-demanding materials. These constituents can enter waterways through the spraying of waste on fields as fertilizer and waste collection in lagoons. Unlined waste lagoons risk groundwater contamination through waste seeps into the water table. High volumes of waste and hazardous levels of pollutants can make their way into surface waters in the event of a waste lagoon leak or overflow as well as through runoff from spray fields.
The combination of extreme rainfall events and the application of manure on agricultural fields poses significant risks of ground and surface water pollution. One particularly noteworthy case was the contamination of North Carolina water supplies following Hurricane Floyd in 1999. Floyd caused a number of swine waste lagoons in Eastern North Carolina to overflow or rupture entirely, causing millions of gallons of untreated swine waste to intermix with the floodwaters.
malodor and Air pollution
If you have visited an animal farm, you will remember the strong smell. The odors common with a small-scale diversified livestock operation are substantially multiplied at CAFOs, due to the sheer number of animals and volume of animal waste contained on site.
The "lagoon-and-sprayfield" approach to waste management, which is common for industrial swine farms, exacerbates the problem of malodor and releases air pollutants such as ammonia and hydrogen sulfide as well as fine dust particles ("particulate matter") into the atmosphere. These pollutants can significantly impact the health and welfare of nearby communities.
In addition to the impacts on the local community, CAFOs pose significant occupational health concerns linked to air quality. Those employed to work in CAFOs can suffer from a number of eye, nose, throat, and upper respiratory ailments from exposure to higher levels of dust, gases, and particulate matter in the confinement barns without proper protective equipment.